View Full Version : [Space] ESA - Rosetta Comet Chaser - Update Thread
Rosetta è la missione scientifica per l'esplorazione spaziale più importante e complessa, oltre che costosa, della storia dell'ESA (per le missioni interamente proprie).
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Si tratta di una sonda spaziale costituita da un'orbiter (la navetta vera e proria) e un lander (Philae). Lo scopo della missione è quello di intercettare una cometa che attraversa ciclicamente il sistema solare (nel caso specifico la cometa 67P/Churyumov-Gerasimenko), orbitarla per due anni in modo da mappare internamente la superficie del nucleo, oltre alla corona, da distanza raccinata e, soprattutto, di far 'appoggiare' un lander sulla sua superficie in modo da studiare in modo diretto la composizione del nucleo della cometa. E' la prima missione al mondo che prevede di orbitare e rilasciare un lander sulla superficie di una cometa. Un'esperimento analogo è stato fatto dalla NASA con la missione Near, ma in quel caso si trattava di un asteroide.
Il nome Rosetta deriva dalla celebre Stele di Rosetta, la pietra con le preziose incisioni egiziane, scoperta nel 1799, che fu la chiave di lettura per conoscere a fondo la civiltà dell'antico Egitto. L'ESA pensa e spera che Rosetta possa costituire una simile chiave per aprire letteralmente al mondo i segreti più intimi delle comete, e dunque dipanare il mistero legato alla nascita del sistema solare. A tal proposito va ricordato che le comete sono originarie di una zone del sistema solare oltre plutone denominata Nube di Oort.
Il lander è stato chiamato Philae, a seguito di un concorso internazionale che ha coinvolto gli studenti di scuole di diversi gradi in tutto il mondo. Ha vinto una ragazzina italiana di 14 anni, Olga Vismara di Arluno (provincia di Milano), che assiterà al lancio di Rosetta dalla base spaziale di Kourou, Guiana Francese. Anche in questo caso il nome, Philae, è legato ad una scoperta archeologica; si tratta di un'isola sul Nilo sulla quale fu trovato un'obelisco con un'iscrizione bilingue che includeva i nomi di Cleopatra e Plotemio in gerofligici egiziani. Questo permise all'archeologo francese Jean-Francois Champollion di utlimare la decifrazione dell'iscrizione sulla Stele di Rosetta.
http://www.esa.int/export/images/3_6_Rosetta_Stone_original_L.jpg
Si tratta della prima missione dell'ESA dedicata ad una cometa dai tempi della missione Giotto (progetto NASA-ESA), che nel 1986 studiò la cometa Halley.
http://www.esa.int/export/images/giotto,1.jpg
ORBITER - Rosetta
La sonda ha dimensioni pari a 2,8 x 2,1 x 2,0 m, più due pannelli solari da 14 m ciascuno (i più grandi mai costruiti, questo perchè la navetta arriverà ad una distanza massima di ben 790 milioni di km dal Sole (5.25 AU), per una superficie totale di quasi 64 mq.
La navetta, oltre agli strumenti principali, ha installato anche una grande antenna a disco (alto guadagno), direzionabile.
Strumenti:
ALICE - Ultraviolet Imaging Spectrometer
CONSERT - Comet Nucleus Sounding
COSIMA - Cometary Secondary Ion Mass Analyser
GIADA - Grain Impact Analyser and Dust Accumulator
MIDAS - Micro-Imaging Analysis System
MIRO - Microwave Instrument for the Rosetta Orbiter
OSIRIS - Rosetta Orbiter Imaging System
ROSINA - Rosetta Orbiter Spectrometer for Ion and Neutral Analysis
RPC - Rosetta Plasma Consortium
RSI - Radio Science Investigation
VIRTIS - Visible and Infrared Mapping Spectrometer
http://www.esa.int/export/images/rosetta_16_l.jpg
LANDER - Philae
Il lander pesa circa 100 kg. E' costruito da un consorzio sotto la direzione dell'Istituto di Ricerca Aerospaziale Tedesco (DLR). Gli altri membri sono la stessa ESA, e vari istituti di paesi europei.
Strumenti:
APXS - Alpha Proton X-ray Spectrometer
ÇIVA / ROLIS - Rosetta Lander Imaging System
CONSERT - Comet Nucleus Sounding
COSAC - Cometary Sampling and Composition experiment
MODULUS PTOLEMY - Evolved Gas Analyser
MUPUS - Multi-Purpose Sensor for Surface and Subsurface Science
ROMAP - RoLand Magnetometer and Plasma Monitor
SD2 - Sample and Distribution Device
SESAME - Surface Electrical and Acoustic Monitoring Experiment, Dust Impact Monitor
http://www.esa.int/export/images/lander-400,0.JPG
COMETA - 67P/Churyumov-Gerasimenko
La cometa 67P/Churyumov-Gerasimenko ha un nucleo di circa 4 km di larghezza. Orbita attorno al sole ogni 6,6 anni, tra 186 e 857 milioni di km dalla nostra stella.
Fu scoperta nel 1969 da K. Churyumov (Università di Kiev, Ucraina) e S. Gerasimenko (Istituto di Astrofisica Dushanbe, Tajikistan).
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LANCIO
Il lancio della missione Rosetta è stato ritardato di un'anno per precauzione a seguito di uno dei primi lanci falliti nel 2002 di una versione potenziata del lanciatore Ariane 5 (5-G). Il problema è poi stato risolto nel corso del 2003, e tutti i lanci seguenti sono avvenuti con successo (con la messa in orbita di 4 satelliti internazionali).
Di conseguenza, il target iniziale, la cometa Wirtanen, è stato cambiato perchè non più raggiungibile nei tempi previsti. Il nuovo obbiettivo, la cometa 67P/Churyumov-Gerasimenko, una delle possibili comete individuate durante lo studio della missione. Nel riconfigurare i parametri della missione necessari per il successo della stessa (in particolare per quanto riguarda il lander), il telescopio spaziale Hubble è stato di grande aiuto. Infatti, tra l'11 e il 12 marzo 2003, Hubble ha seguito e fotografato per 21 ore la nuova cometa, osservando che è più grande di tre volte del prcedente obbiettivo, ma la sua forma a "pallone di football" rende possibile l''atterraggio' del lander senza difficoltà particolari.
Il lancio è previsto (per la prima finestra disponible) nelle prime ore del 26 febbraio 2004, con il 158 volo del lanciatore Ariane 5-G, dalla base spaziale europea di Kourou, Guiana Francese.
Dopo il burn-out del primo stadio, lo stadio superiore con la navetta rimarrà in orbita stazionaria (EPO, Earth Parking Orbit) per circa due ore, dopodichè vi sarà l'accensione dello stadio superiore per lanciare Rosetta nella sua traiettoria interplanetaria.
Il peso totale è di circa 3000 kg al lancio, inclusi 1670 kg di propellente, 165 kg di strumentazione scientifica e 100 kg del lander.
VIAGGIO
Il viaggio di Rosetta durerà circa 10 anni, e coprirà una distanza massima dal sole di circa 5,25 unità astronomiche (UA, pressapoco 790 milioni di km).
Lancio: (Febbraio 2004)
Primo passaggio della Terra: (Novembre 2005)
Passaggio di Marte: (Febbraio 2007)
Secondo passaggio della Terra: (Novembre 2007)
Terzo passaggio della Terra: (Novembre 2009)
Ibernazione nello spazio profondo: (Maggio 2011 - Giugno 2014)
Intercettazione cometa: (Gennaio-Maggio 2014)
Mappatura/caratterizzazione cometa: (Agosto 2014)
Atterragio del lander sulla cometa: (Novembre 2014)
Inseguimento attorno al sole: (Novembre 2014 - Dicembre 2015)
Rosetta seguirà quindi la cometa 67P/Churyumov-Gerasimenko nella sua orbita ciclica attorno al Sole, osservando cosa succede al suo nucleo giacciato mentre incontra la stella e si allontana.
La missione termina nel dicembre 2015.
Rosetta passerà poi un'ultima volta attorno alla Terra, più di 4000 giorni dopo l'inizio della sua avventura.
OPERAZIONI
Mission Operations Centre: European Space Operations Centre (ESOC), Darmstadt, Germany
Prime Ground Station: New Norcia, near Perth, Australia
Science Operations Centre: Collocated at ESOC (Darmstadt, Germany) and ESTEC (Noordwijk, Netherlands)
Lander Control Centre: DLR, Cologne, Germany
Lander Science Centre: CNES, Toulouse, France
Durata stimata missione Rosetta: 12 anni
Sito ufficiale - Overview: ESA - Rosetta (http://www.esa.int/export/SPECIALS/Rosetta/SEMYMF374OD_0.html)
Sito ufficiale - Rosetta Science:
ESA - Rosetta Science (http://www.esa.int/export/esaSC/120389_index_0_m.html)
Altre missioni relative a comete:
- NASA - Deep Impact (http://deepimpact.jpl.nasa.gov/)
- NASA - Stardust (http://stardust.jpl.nasa.gov/)
Rosetta _ A New Target To Solve Planetary Mysteries
Paris - Jan 27, 2004
Rosetta is scheduled to be launched on board an Ariane-5 rocket on 26 February from Kourou, French Guiana. Originally timed to begin about a year ago, Rosetta's journey had to be postponed, as a precaution, following the failure of a different version of Ariane-5 in December 2002. This will be the first mission to orbit and land on a comet, one of the icy bodies that travel throughout the Solar System and develop a characteristic tail when they approach the Sun.
http://www.spacedaily.com/images/rosetta-marker-bg.jpg
Not long now to launch, but a decade and more to Comet Churyumov- Gerasimenko
This delay meant that the original mission's target, Comet Wirtanen, could no longer be reached. Instead, a new target has been selected, Comet 67P/Churyumov-Gerasimenko, which Rosetta will encounter in 2014 after a 'billiard ball' journey through the Solar System lasting more than ten years. Rosetta's name comes from the famous 'Rosetta Stone', from which Egyptian hieroglyphics were deciphered almost 200 years ago. In a similar way, scientists hope that the Rosetta spacecraft will unlock the mysteries of the Solar System.
Comets are very interesting objects for scientists, since their composition reflects how the Solar System was when it was very young and still 'unfinished', more than 4600 million years ago. Comets have not changed much since then. In orbiting Comet Churyumov-Gerasimenko and landing on it, Rosetta will collect information essential to an understanding of the origin and evolution of our Solar System.
It will also help discover whether comets contributed to the beginnings of life on Earth. In fact comets are carriers of complex organic molecules that, delivered to Earth through impacts, perhaps played a role in the origin of living forms. Furthermore, 'volatile' light elements carried by comets might also have played an important role in forming the Earth's oceans and atmosphere.
"Rosetta is one of the most challenging missions undertaken so far," says Professor David Southwood, ESA Director of Science. "No one has ever attempted such a mission, unique for its scientific implications as well as for its complex and spectacular interplanetary space manoeuvres."
Before reaching its target in 2014, Rosetta will circle the Sun four times on wide loops in the inner Solar System. During its long trek, the spacecraft will have to endure some extreme thermal conditions. Once it is close to Comet Churyumov-Gerasimenko, scientists will take it through a delicate braking manoeuvre; the spacecraft will then closely orbit the comet, and gently drop a lander on it. It will be landing on a small, fast-moving 'cosmic bullet' about whose 'geography' very little is known yet.
An amazing 10-year interplanetary trek
Rosetta is a three-tonne box-type spacecraft about three metres high, with two 14-metre solar panels. It consists of an orbiter and a lander. The lander is approximately one metre across and 80 centimetres high. It will be attached to the side of the orbiter during the journey to Comet Churyumov-Gerasimenko. Rosetta carries 21 experiments in total, 10 of them on the lander. They will be kept in hibernation during most of its 10-year trek towards the comet.
Why does Rosetta's cruise need to take so long? To reach Comet Churyumov-Gerasimenko, the spacecraft needs to go out into deep space as far out from the Sun as Jupiter. No launcher could possibly get Rosetta there directly. ESA's spacecraft will gather speed from gravitational 'kicks' provided by four planetary fly-bys: one of Mars in 2007 and three of Earth in 2005, 2007 and 2009.
During the trip, Rosetta will also twice pass through the asteroid belt, where a fly-by with one or more of these primitive objects is possible. A number of candidate targets have already been identified, but the final selection will be made after launch, once the amount of surplus fuel has been verified by mission engineers. During these encounters, scientists plan to switch on Rosetta's instruments for scientific studies of these largely unexplored Solar System bodies.
Long trips in deep space include many hazards, such as extreme changes in temperature. Rosetta will leave the benign environment of near-Earth space to the dark, frigid regions beyond the asteroid belt. To manage these thermal loads, experts have done very tough pre-launch tests to study Rosetta's endurance. For example, they have heated its external surfaces to more than 150°C, then cooled it to -150°C in the next test.
The spacecraft will be fully reactivated prior to the comet rendezvous manoeuvre in 2014. Then, Rosetta will orbit the comet _ an object only about 4 kilometres in diameter - while it cruises through the inner Solar System at 135 000 kilometres per hour.
At the time of the rendezvous _ around 675 million kilometres from the Sun _ Comet Churyumov-Gerasimenko will hardly show any surface activity. This means that the characteristic 'coma' (the comet's 'atmosphere') and the tail will not be formed yet, because of the distance from the Sun.
The comet's tail is in fact made of dust grains and frozen gases from the comet's surface that vaporise because of the Sun's heat. Over a period of six months, Rosetta will extensively map the comet's surface, prior to selecting a landing site.
In November 2014, the lander will be ejected from the spacecraft from a height which could be as low as one kilometre. Touchdown will be at walking speed, about one metre per second. Immediately after touchdown, the lander will fire a harpoon into the ground to avoid bouncing off the surface back into space, since the comet's extremely weak gravity alone would not hold onto the lander.
Operations and scientific observations on the surface will last at least a week, but may continue for many months. Besides taking close-up pictures, the lander will drill into the dark organic crust and sample the primordial ices and gases.
During and after the lander operations, Rosetta will continue orbiting and studying the comet: it will be the first spacecraft to witness at close quarters the changes taking place in a comet when the comet approaches the Sun and grows its coma and tail and then travels away from it. The trip will end in December 2015, after 12 years of adventure, when the comet has made its closest approach to the Sun and is on its way towards the outer Solar System.
Studying a comet on the spot
Rosetta's goal is to examine the comet in great detail. The instruments on the orbiter include several cameras and spectrometers that work at different wavelengths: infrared, ultraviolet, visible and microwave. In addition, there are various other instruments to make in situ analysis.
Together, they will provide, amongst other things, very high-resolution images and information about the shape, density, temperature and chemical composition of the comet. Rosetta's instruments will analyse the gases and dust grains in the coma that forms when the comet becomes active, as well as the interaction with the solar wind.
The ten experiments on the lander will make an on-the-spot analysis of the composition and structure of the comet's surface and subsurface material. A drilling system will take samples down to 30 centimetres below the surface and feed these to the 'composition analysers'. Other instruments will measure properties such as near-surface strength, density, texture, porosity, ice phases and thermal properties. Microscopic studies of individual grains will tell us about the texture.
Ground operations
All scientific data including those relayed from the lander will be stored on the orbiter for downlink to Earth at the next ground station contact. ESA has installed a new deep-space antenna at New Norcia, near Perth in Western Australia, as the main communications link between the spacecraft and ESOC Mission Control in Darmstadt, Germany.
This 35-metre diameter parabolic antenna allows the radio signal to reach distances of more than a million kilometres from Earth. The radio signals, travelling at the speed of light, will take up to 50 minutes to cover the distance between the spacecraft and Earth.
Rosetta's Science Operations Centre, which will be responsible for collecting and distributing the scientific data, will share locations at ESOC and ESTEC in Noordwijk, The Netherlands. The Lander Control Centre is located at DLR in Cologne, Germany, and the Lander Science Centre at CNES in Toulouse, France.
Building Rosetta
Rosetta was selected as a mission in 1993. The spacecraft has been built by Astrium Germany as prime contractor. Major subcontractors are Astrium UK (spacecraft platform), Astrium France (spacecraft avionics), and Alenia Spazio (assembly, integration, and verification). Rosetta's industrial team involves more than 50 contractors from 14 European countries, Canada and the United States.
Scientific consortia from institutes across Europe and the United States have provided the instruments on the orbiter. A European consortium under the leadership of the German Aerospace Research Institute (DLR) has provided the lander. Rosetta has cost ESA EUR 770 million at 2000 economic conditions. This includes the launch and the entire period of development and mission operations from 1996 to 2015. The lander and the experiments, the so-called 'payload', are not included since they are funded by the member states through scientific institutes.
Europe is a leading pioneer in comet exploration. In 1986, ESA's Giotto spacecraft performed the closest comet fly-by ever achieved by any spacecraft (at a distance of 600 kilometres from Halley). It sent back wonderful pictures and data that showed that comets contain complex organic molecules.
These kinds of compounds are rich in carbon, hydrogen, oxygen, and nitrogen. Intriguingly, these are the elements which make up nucleic acids and amino acids, which are essential ingredients for life as we know it.
Giotto continued its successful journey and flew within about 200 km of Comet Grigg-Skjellerup in 1992. Now scientists will be eagerly waiting to be able to answer some of the fascinating new questions that arose from analysing the exciting results from Giotto.
Other past missions that have flown by a comet are: NASA's ICE mission in 1985, the two Russian Vega spacecraft and the two Japanese spacecraft Suisei and Sakigake that were part of the armada that visited Comet Halley in 1986; NASA's Deep Space 1 flew by Comet Borelly in 2001 and NASA's Stardust, which flew by Comet Wild 2 earlier this month and has captured samples of the comet's coma to be returned in 2006.
Unfortunately NASA's Contour launched in summer 2002 failed when it was inserted into its interplanetary trajectory. Later this year we shall also see the launch of Deep Impact, a spacecraft that will shoot a massive block of copper into a comet's nucleus.
Rosetta Lander Named Philae
Paris (ESA) Feb 09, 2004
With just 17 days to the launch of the European Space Agency's Rosetta comet mission, the spacecraft's lander was named "Philae" in a ceremony last week in Paris. Rosetta embarks on a 10-year journey to Comet 67P/Churyumov-Gerasimenko from Kourou, French Guiana, on 26 February.
http://www.spacedaily.com/images/rosetta-lander-bg.jpg
Philae is the island in the river Nile on which an obelisk was found that had a bilingual inscription including the names of Cleopatra and Ptolemy in Egyptian hieroglyphs. This provided the French historian Jean-Francois Champollion with the final clues that enabled him to decipher the hieroglyphs of the Rosetta Stone and unlock the secrets of the civilisation of ancient Egypt.
Just as the Philae Obelisk and the Rosetta Stone provided the keys to an ancient civilisation, the Philae lander and the Rosetta orbiter aim to unlock the mysteries of the oldest building blocks of our Solar System - comets.
Germany, France, Italy and Hungary are the main contributors to the lander, working together with Austria, Finland, Ireland and the UK. The main contributors held national competitions to select the most appropriate name.
Philae was proposed by 15-year-old Serena Olga Vismara from Arluno near Milan, Italy. Her hobbies are reading and surfing the internet, where she got the idea of naming the lander Philae. Her prize will be a visit to Kourou to attend the Rosetta launch.
Study of Comet Churyumov-Gerasimenko will allow scientists to look back 4600 million years to an epoch when no planets existed and only a vast swarm of asteroids and comets surrounded the Sun. On arrival at the comet in 2014, Philae will be commanded to self-eject from the orbiter and unfold its three legs, ready for a gentle touchdown.
Immediately after touchdown, a harpoon will be fired to anchor Philae to the ground and prevent it escaping from the comet's extremely weak gravity. The legs can rotate, lift or tilt to return Philae to an upright position.
Philae will determine the physical properties of the comet's surface and subsurface and their chemical, mineralogical and isotopic composition. This will complement the orbiter's studies of the overall characterisation of the comet's dynamic properties and surface morphology. Philae may provide the final clues enabling the Rosetta mission to unlock the secrets of how life began on Earth.
"Whilst Rosetta's lander now has a name of its own, it is still only a part of the overall Rosetta mission. Let us look forward to seeing the Philae lander, Osiris, Midas and all the other instruments on board Rosetta start off on their great journey this month," said Professor David Southwood, ESA Director of Science.
A Comet Tale: At Last, Europe's Rosetta Mission is Ready for Flight
By Tariq Malik
Staff Writer
posted: 06:30 am ET
04 February 2004
After a year of delays and a completely reworked mission, the European Space Agency (ESA) is gearing up for Rosetta, an international effort to send two spacecraft on a cosmic date with one of the snowballs of the universe.
Set for a Feb. 26 launch, with two potential windows spaced 20 minutes apart, Rosetta should finally begin its trek to Comet 67P/Churyumov-Gerasimenko, a ball of ice, dirt and dust that sweeps through the Solar System almost every six years or so. The mission is twofold, consisting of an orbiter expected to circle the comet upon arrival and a small lander to touchdown on the icy traveler shortly thereafter.
"All systems are green…and we are all go now," said Rosetta project scientist Gerhard Schwehm, of ESA. "I think we have a wonderful spacecraft here."
The upcoming launch is a redemption of sorts for Rosetta planners, who saw their original plans evaporate last year after the Ariane-5 rocket booster for a separate mission failed. ESA officials delayed Rosetta's launch indefinitely, a setback that kept Rosetta from visiting its initial target, the Comet Wirtanen.
However, ission planners were able to find a suitable replacement, Churyumov-Gerasimenko, a 2.5-mile (four-kilometer) wide collection of ice and dirt that speeds through the Solar System at about 83,800 miles (135,000 kilometers) an hour.
Today, Schwehm said, Rosetta's orbiter and lander is one of ESA's most complex scientific payloads ever designed for Solar System research. But the two spacecraft still have a 10-year journey ahead of them before reaching their final destination. If everything goes as planned, the mission should meet up with Comet Churyumov-Gerasimenko in 2014.
A mission built for two
Rosetta takes its name from the Rosetta Stone, which gave archaeologists the tools to decipher Egyptian hieroglyphics. Project scientists hope their orbiter-lander mission is the astronomical equivalent of its namesake, giving astronomers the tools they need to decipher the nature of comets.
"We know very little, ultimately, about comets," said Claudia Alexander, project manager and project scientist for the NASA contingent of the mission, adding that once Rosetta arrives at its final target, the mission will enter a phase akin to the Galileo probe's arrival at Jupiter. "We are going to be learning very fast then."
Altogether, Rosetta is taking 21 scientific instruments to Comet Churyumov-Gerasimenko, which breaks down to 11 on the orbiter and 10 on the lander. Among the instrument suit are cameras to take high-resolution images of the comet's surface and shape, various spectrophotometers to study its chemical composition, as well as instruments to measure the gases and dust that spew from Churyumov-Gerasimenko as it approaches the Sun.
The mission's flight profile calls for the orbiter-lander combo to meet up with Comet Churyumov-Gerasimenko about 4.5 astronomical units (AU) from the Sun. One AU, or astronomical unit, is the distance from the Earth to Sun, about 93 million miles (150 million kilometers).
The comet should still be relatively inactive at the start of the mission, Schwehm said, allowing project scientists a ringside seat to Churyumov-Gerasimenko when it begins to expel gas and form its tail. Rosetta planned mission runs about two years, following the comet until it reaches its closest point to the Sun.
Colliding softly with a comet
A few months after its 2014 arrival at Comet Churyumov-Gerasimenko, Rosetta's lander is designed to self-eject and start its own studies.
Since the lander doesn't use a rocket engine to control the descent, just a small reaction control system, its survival depends on the orbiter matching the relative speed of the comet, allowing it to trace a slow, ballistic trajectory to Churyumov-Gerasimenko's surface. Three landing struts are designed to absorb any impact shock, and can lift or tilt the lander to keep it in an upright position.
"We have harpoons that will anchor the lander to the comet," Schwehm said. "The comet [has] a low gravity, so if you come at it with a propulsion system, you'll jump right off again."
Schwehm said that the lander is expected to fall toward the planet slowly, and should hit the comet surface at a speed of about three feet (one meter) per second.
"It's something like a pedestrian walking into a wall, but we really don't know for sure," Schwehm said. "This [unknown] is something we have to cope with, because nobody knows what the comet is like up close."
Schwehm added that unlike Rosetta's orbiter, the lander was built specifically for its first target, Comet Wirtanen, which is smaller than Churyumov-Gerasimenko and has less gravity. While mission planners believe the lander can handle the additional stresses, they can only find out once Rosetta reaches its target.
Rosetta engineers included a drilling system among the lander's instruments, some of which mirror those on the orbiter, to study sample materials from beneath the comet surface. Data from the lander can only reach Earth after being relayed through the orbiter.
More than one of first
In addition to being the first mission to land on a comet, Rosetta is expected to debut a few new instruments in space, one of which is from the mission's American contingent, Schwehm said.
Researchers at NASA's Jet Propulsion Laboratory (JPL) in California have built the first microwave instrument to be used for planetary science. The instrument, aptly named the Microwave Instrument for the Rosetta Orbiter (MIRO) will be used to analyze Comet Churyumov-Gerasimenko's rate of outgassing, as well as the temperature just below the surface of the comet's nucleus.
"There have been some of these instruments used on Earth for terrestrial science and atmospheric studies, but they are enormous and costly," Alexander said, adding that those Earth instruments can each weigh up to 440 pounds (200 kilograms), more than Rosetta's entire scientific payload. JPL scientists were able to cut MIRO's weight down to about 44 pounds (20 kilograms), she added.
NASA also contributed in part to ROSINA, one of the most sophisticated mass spectrometers ever to fly in space. Led by investigators in Switzerland, Rosetta will use the ROSINA instrument to determine the composition of Comet Churyumov-Gerasimenko's atmosphere, ionosphere and the speeds of individual gas particles.
ROSINA should also be able to carbon date comet fragments, which could tell scientists how long the icy traveler has existed.
"We're going to be able to tell the age of the comet," Alexander said with enthusiasm.
Long-distance solar power
The key to Rosetta's success ultimately depends on its power supply, two massive solar panels that stretch out 45 feet (14 meter) from each side of the orbiter. Project engineers specially designed the panels to operate at low temperatures and cull the most power from the low-intensity sunlight it will receive during its mission.
"I think we're setting a record for the farthest use of solar panels from the sun," Schwehm said. "[NASA's] Stardust used them from outside 2 AU, but we will reach out even farther."
Rosetta's solar panels are responsible for keeping the spacecraft primed for its cometary rendezvous for its 10-year transit through the Solar System, generating about 395 watts of power at the low end and 850 watts at the high. At its farthest point form the Sun, the orbiter/lander duo will be about 5.25 AU away - to the orbit of Jupiter - before it falls back Sunward towards its date with Comet Churyumov-Gerasimenko.
Through much of the pre-rendezvous trip, Rosetta will be in a hibernation mode, generating only enough power keep its sensitive instruments from freezing in the cold of space. Mission controllers plan to awaken the spacecraft briefly in 2008 during its pass through the asteroid belt to study nearby space rocks, though definite targets won't be announced until later.
A rocky road into space
Despite its upcoming launch, Rosetta has certainly had its share of mission headaches.
The spacecraft's original flight plan called for a 2003 launch with a Comet Wirtanen in Rosetta's crosshairs. But ESA scrubbed that launch after an Ariane-5 rocket failed in December 2002.
The launch failure cast a pall over Rosetta scientists after their mission was put on indefinite delay, cutting their chances of a successful Wirtanen rendezvous. After some quick number crunching, mission planners settled on Churyumov-Gerasimenko, one of a number of original targets they had to choose from, as a viable alternative target.
"Last year we were pretty glum knowing that we were facing launch delay," Alexander told SPACE.com. "But now we're really there and I'm really looking forward to the extended mission. The years in between are going to go by fast."
The comet target switcheroo, however, was not without cost. To get to Churyumov-Gerasimenko, Rosetta has to swing by Earth not once but three times, starting in 2005 with subsequent passes every two years after. A Mars flyby in 2007 is also required to fling the spacecraft through the asteroid belt.
"The first step is to get into orbit and have an excellently working spacecraft," Schwehm said. "But even if it takes 10 years, [the science] is worth waiting for. After such a long launch delay, our scientists deserve it."
Rosetta is ESA's second dedicated comet rendezvous. The first, Giotto, visited two of the icy space snowballs starting with a historic pass by the famed Comet Halley in 1986. Six years later Giotto made its second cometary rendezvous during a flyby of Comet Grigg-Skjellup.
MONDAY, FEBRUARY 16, 2004
The Rosetta comet probe that will embark on its long-awaited journey next week was attached to its Ariane 5 launcher Monday inside a cavernous assembly building at the South American launch site.
Fully fueled with over 3,600 pounds of toxic maneuvering propellant, Rosetta was lowered atop the Ariane 5's upper stage inside the final assembly building at the Guiana Space Center in Kourou, located along South America's northeast Atlantic coast.
The milestone was one met with great anticipation by project officials, with just ten days remaining until Rosetta is placed into solar orbit to begin a voyage to comet Churyumov-Gerasimenko that will span over a decade.
Sitting in a Kourou high bay for the past year after officials elected to opt out of a launch opportunity in 2003 due to rocket concerns, Rosetta began the run-up to a second launch campaign last fall with the testing of key equipment.
Assembly operations for the Ariane 5G+ rocket began January 19, and the vehicle's upper stage was attached January 21. Fueling of the spacecraft with its volatile load of fuel and oxidizer propellant took place over January 27 and 28.
With its twin solid rocket boosters now bolted on, the Ariane 5 rolled out of its launcher integration building February 10 for the half-hour ride on dual rail tracks to the final assembly building where it would soon receive its payload.
With Rosetta now firmly in place atop the Ariane 5 stack, the payload fairing will be attached to enclose the probe for protection during the few minutes of ascent through the atmosphere.
The completed rocket will roll out to the launch pad February 24, in advance of the anticipated liftoff February 26 at 0716 GMT (2:16 a.m. EST) from the ELA-3 pad in Kourou.
Stay with Spaceflight Now for continued updates and extensive coverage of the launch of Rosetta next week.
ESA's Rosetta comet chaser ready for lift-off
17 February 2004
ESA PR 11-2004
Follow the Rosetta launch from an ESA or Arianespace establishment
On 26 February at 04:36 a.m. Kourou time (07:36 a.m. GMT - 08:36 a.m. CET), Rosetta is scheduled to be launched on board an Ariane-5 launcher from the European Spaceport in Kourou, French Guiana.
Originally timed to begin about a year ago, Rosetta's journey had to be postponed. This delay meant that the original mission's target, Comet Wirtanen, could no longer be reached. Instead, a new target has been selected, Comet Churyumov-Gerasimenko, which Rosetta will encounter in 2014 after a "billiard ball" journey through the Solar System lasting more than ten years. This will be the first mission to orbit and land on a comet.
Media representatives in Europe can follow the launch of Rosetta and initial orbital operations at ESA/Darmstadt (ESOC) in Germany - which will be acting as the main European press centre - ESA/Noordwijk (ESTEC) in the Netherlands or ESA/Frascati (ESRIN) in Italy. At each site ESA specialists will be available for interviews. Also Arianespace at Evry will cater for media.
però dovrebbero fare un corso presso gli americani per trovare nomi decenti alle missioni :D
Rosetta powerd by intel centrino :rotfl:
Originariamente inviato da mrc
però dovrebbero fare un corso presso gli americani per trovare nomi decenti alle missioni :D
Rosetta powerd by intel centrino :rotfl:
:confused:
Se leggevi si capiva il riferimento alla Stele di Rosetta, che ha permesso di conoscere a fondo la civiltà egizia.
Links missione:
- ESA - Rosetta Mission (http://www.esa.int/export/SPECIALS/Rosetta/index.html)
- ESA - Rosetta Science (http://www.esa.int/export/esaSC/120389_index_0_m.html)
- ESA - Rosetta Scientific and Technical website (http://sci.esa.int/science-e/www/area/index.cfm?fareaid=13)
- ESA - Rosetta Journal - Multimedia (http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=31063&farchive_objecttypeid=18&farchive_objectid=30912) (foto e video)
Coyote74
20-02-2004, 15:37
Questa missione mi ricorda un po' Armageddon...:D
Comunque da buon Ingegnere Aerospaziale non posso che essere felice della cosa. L'Europa finalmente sarà la prima ad intraprendere una missione spaziale mai tentata prima. Bene così....
Originariamente inviato da Coyote74
Comunque da buon Ingegnere Aerospaziale non posso che essere felice della cosa.
Che fai di bello, lavori? Se si, dove? :)
Ma cosa continui ad aprire i thread che oramai non si riesce più a star dietro a tutti! :D
"piccoli" pannelli solari...
http://sci.esa.int/science-e-media/img/7d/ACFLQA0saWWW.jpg
http://sci.esa.int/science-e-media/img/6b/lores_34155.jpg
Crossposting... :spam: :D
Originariamente inviato da gpc
Ma cosa continui ad aprire i thread che oramai non si riesce più a star dietro a tutti! :D
Mmhh, e io che volevo aprirne giusto un altro pò... :(
:sofico:
Originariamente inviato da GioFX
Mmhh, e io che volevo aprirne giusto un altro pò... :(
:sofico:
Sei il Gik25 dell'astronomia :sofico:
Originariamente inviato da gpc
Crossposting... :spam: :D
:O :sofico:
Originariamente inviato da gpc
Sei il Gik25 dell'astronomia :sofico:
:eek: :eek:
...et tecnologia aerospaziale, please! :O
Salve a tutti, oggi ho partecipato ad una conferenza con Guidoni organizzata dalla mia scuola, è stato interessante.
Byezz ;)
Coyote74
20-02-2004, 17:53
Originariamente inviato da GioFX
Che fai di bello, lavori? Se si, dove? :)
Lavoro per una ditta che produce macchinari industriali per la lavorazione del vetro. Non centra un ca**o con i miei studi, ma per sopravvivere si fa questo ed altro:D Comunque ho intenzione di fare domanda presso l'Alenia e vediamo come va....
Originariamente inviato da Coyote74
Lavoro per una ditta che produce macchinari industriali per la lavorazione del vetro. Non centra un ca**o con i miei studi, ma per sopravvivere si fa questo ed altro:D Comunque ho intenzione di fare domanda presso l'Alenia e vediamo come va....
volevo farla anch'io (anche se sono informatico), ma roma, torino e taranto sono troppo lontani :D
Coyote74
20-02-2004, 22:52
Per me Torino non sarebbe lontano, anche se ci sarebbero una serie di problematiche da risolvere, visto che dovrei fare sicuramente il pendolare e quindi non so fino a quando potrei resistere. Comunque un'esperienza del genere mi affascina parecchio, anche a costo di sacrifici, visto che adesso ho il lavoro proprio vicino a casa (è per questo che l'ho scelto).
Rosetta comet chaser to launch Thursday morning
Europe's vaunted $1 billion Rosetta comet explorer is poised to set off on its decade-long journey early Thursday morning. In the last major event before the final countdown begins, the Ariane 5 rocket rolled out of its assembly building to the launch pad Tuesday.
Rosetta launch timeline (http://spaceflightnow.com/ariane/v158/040224ascent.html)
Rosetta mission set for launch
Posted: Tue, Feb 24 7:49 PM ET (0049 GMT)
Rosetta, ESA's ambitious mission to rendezvous with and land on a comet, is on track for a launch early Thursday. Rosetta is scheduled for launch at 2:36 am EST (0736 GMT) on an Ariane 5 booster from Kourou, French Guiana. The spacecraft, composed of an orbiter and a lander named Philae, will spend ten years traveling through the solar system, adjusting its trajectory through a series of flybys — three of Earth and one of Mars — before reaching the comet Churyumov-Gerasimenko. Rosetta will then spend more than a year studying the comet and deploying Philae to land on the surface of the comet's nucleus. Rosetta was scheduled to launch in January 2003 on a mission to another comet, Wirtanen, but the launch was delayed to allow time to investigate an Ariane 5 launch failure in December 2002. The delay meant the spacecraft missed its narrow launch window, requiring ESA to redesign the mission to visit another comet.
WEDNESDAY, FEBRUARY 25, 2004
Europe's vaunted $1 billion Rosetta comet explorer is poised to set off on its decade-long journey early Thursday morning from the same South American launch site that hosted the start of the continent's first deep space mission 19 years ago.
In the last major event before the final countdown begins, the Ariane 5 rocket rolled out of its assembly building to the launch pad Tuesday.
A year later than first planned, Rosetta is due to begin its lengthy voyage Thursday at 0736:49 GMT (2:36:49 a.m. EST) from the ELA-3 launch pad in Kourou, French Guiana.
Overall, officials have until March 17 to get Rosetta off the ground or else await another launch opportunity.
It will take more than two hours for Rosetta to be delivered into a solar orbit that will see it intercept Earth again next March for a pivotal gravity assist fly-by.
Rosetta will be setting off toward comet Churyumov-Gerasimenko, an icy space rock the size of a small town that was selected for investigation last spring after the first opportunity to send Rosetta to another comet was passed up due to concerns with the reliability of its Ariane 5 rocket.
Before arriving in orbit around the comet in the summer of 2014, the Rosetta probe will swing by Earth three times and Mars once to put it on course to intercept Churyuomov-Gerasimenko when it dips back into the inner solar system in the next decade.
Rosetta will also be put in a hibernation period from July 2011 to January 2014 when all systems except the main computer will be switched off.
Once in orbit, Rosetta will drop a small 200-pound lander onto the surface to carry out its own experiments. The orbiter will continue observations of the primordial space rock for several months until late 2015 when the comet makes its closest approach to the Sun.
After the 6,743-pound Rosetta was attached to the Ariane 5 upper stage February 16, the two halves of the Ariane's payload fairing were placed around the probe on February 18.
The storable propellant upper stage was filled with its load of hydrazine fuel and nitrogen tetroxide oxidizer last Thursday, February 19, followed the next day by a final countdown and launch rehearsal for the team.
Senior officials gathered on Monday to confirm the readiness of the vehicle for flight. Having issued formal permission to proceed with preparations, additional work was done to ready the rocket to roll to the launch pad Tuesday.
The final countdown will get underway Wednesday at 2007 GMT (3:07 p.m. EST). A check of electrical systems is scheduled to occur at 0007 GMT Thursday (7:07 p.m. EST Wednesday). At 0247 GMT (9:47 p.m. EST), super-cold liquid hydrogen and liquid oxygen propellants will begin flowing into the Ariane 5's massive cryogenic first stage to fuel its single Vulcain powerplant. A chilldown of the Vulcain engine will take place at about 0417 GMT (11:17 p.m. EST). A final check of connections between the launcher and telemetry, tracking, and command systems is slated for around 0627 GMT (1:27 a.m. EST).
If all systems are deemed ready for launch, controllers will allow the countdown to enter a computer-controlled phase known as the synchronized launch sequence seven minutes prior to liftoff. Following this critical milestone is a series of fast-paced events culminating with ignition of the Vulcain main engine when the count reaches zero. The twin solid rocket boosters will fire to life seven seconds later, followed immediately by liftoff.
Flight 158 will follow a unique launch profile on its mission to place Rosetta on an Earth escape trajectory and into solar orbit. The solid-fueled boosters will burn for two minutes, 20 seconds before jettisoning. The nose cone shielding Rosetta from the elements is let go about a minute later. The first stage's Vulcain main engine will continue to fire until about ten minutes into flight, when it will shut down having consumed all its fuel.
In a departure from the vast majority of Ariane 5 launches, the upper stage will enter a long coast phase before finally igniting over the Pacific Ocean nearly two hours after liftoff. Burning for 17 minutes, it will inject Rosetta onto the initial course that will ultimately see it arrive in the vicinity of comet Churyumov-Gerasimenko in about 123 months. Separation of the spacecraft from the upper stage is expected about two hours and 15 minutes into the flight.
Flight 158 will mark the 162nd Ariane launch overall since 1979, and the first for the rocket in 2004. It also will be the 18th use of the Ariane 5 rocket since being originally introduced in 1996.
Stay with Spaceflight Now for live play-by-play updates during the launch of the Ariane 5 rocket with Rosetta.
Flight 158
February 24: Ariane 5 is in the launch zone with its Rosetta payload
The ELA-3 launch zone at Europe's Spaceport is once again alive with activity following the rollout of Flight 158's Ariane 5 this morning.
Emerging into the sunlight at 3:30 p.m., the completed Ariane 5 moved along a 2.8-km.-long dual rail line that links the Final Assembly Building with the launch zone.
Flight 158's Ariane 5 Generic vehicle is installed on a massive mobile launch table, which was locked into position in the ELA-3 launch zone after its arrival at approximately 4:20 p.m. This positioned it over large flame ducts that direct exhaust from Ariane 5's two solid rocket motors and the core stage's Vulcain cryogenic main engine.
Liftoff of Flight 158 will occur in the early morning hours of February 26. This mission uses a very specific launch slot instead of the typical launch window for Ariane 5 missions that carry geostationary satellite payloads. Because of the unique mission profile with the Rosetta comet-intercept spacecraft, the exact launch time has been set for 49 seconds past 4:36 a.m.
The duration of Flight 158 also is unusual for an Ariane 5 mission. After liftoff, booster separation and burnout of the central core stage, Ariane 5's EPS upper stage will enter a prolonged ballistic phase, followed by its delayed ignition at almost 2 hours after liftoff. Rosetta will then be separated from the stage approximately 14 minutes later, embarking on an Earth escape trajectory that will lead to its encounter with Comet Churyumov-Gerasimenko in 2014.
Rosetta was developed in a European Space Agency program and was built by an industrial team involving more than 50 contractors from 14 European countries and the United States. The prime spacecraft contractor is Astrium Germany, and major subcontractors are Astrium UK (for the spacecraft platform), Astrium France (spacecraft avionics) and Alenia Spazio (assembly, integration and verification).
Rosetta - Launch Live Webcast (http://esa.capcave.com/esa/rosetta/)
Flight 158 - February 25
Final countdown underway for Ariane 5 and Rosetta
http://www.arianespace.com/site/images/158launchpad_lg.jpg
All is on schedule for tomorrow's early morning liftoff of Arianespace Flight 158, with the countdown proceeding on schedule at the Spaceport in French Guiana.
Both the Ariane 5 and its Rosetta comet-intercept spacecraft are "green" for launch as the preparations enter their final phase.
Today was another sunny day in French Guiana, and the weather forecast for tomorrow morning's launch slot also is favorable.
Due to the unique mission profile with the Rosetta comet-intercept spacecraft, the exact launch time has been set for 49 seconds past 4:36 a.m. on February 26.
Flight 158 will be the 14th commercial Ariane 5 mission performed under Arianespace management.
Its Rosetta spacecraft payload is a deep-space probe that will be placed on an Earth escape trajectory that will lead to its encounter with Comet Churyumov-Gerasimenko in 2014.
THURSDAY, FEBRUARY 26, 2004
0706 GMT (2:06 a.m. EST)
The final minutes of the countdown are ticking at the Guiana Space Center for today's launch of the Rosetta spacecraft aboard the Ariane 5 rocket. Liftoff is scheduled for 0736:49 GMT.
The European Space Agency's Rosetta mission represents several historic firsts:
- Rosetta will be the first spacecraft to orbit a comets nucleus.
- It will be the first spacecraft to fly alongside a comet as it heads towards the inner Solar System.
- Rosetta will the first spacecraft to examine from close proximity how a frozen comet is transformed by the warmth of the Sun.
- Shortly after its arrival at Comet 67P/Churyumov-Gerasimenko, the Rosetta orbiter will despatch a robotic lander for the first controlled touchdown on a comet nucleus
- The Rosetta landers instruments will obtain the first images from a comets surface and make the first in-situ analysis to find out what it is made of.
- On its way to Comet 67P/Churyumov-Gerasimenko, Rosetta will pass through the main asteroid belt, with the option of a first close encounter with one or more of these primitive objects
- Rosetta will be the first spacecraft ever to fly close to Jupiter's orbit using solar cells as its main power source.
Arianespace - Live (http://www.streamingbox.com/arianespace/v3/launcher.php?langue=en)
THURSDAY, FEBRUARY 26, 2004
0720 GMT (2:20 a.m. EST)
SCRUB! Today's launch of the Ariane 5 rocket carrying the Rosetta spacecraft has been postponed due to unfavorable high-altitude winds. Liftoff has been rescheduled for early Friday morning.
"We have a weather no-go because of the winds at altitude. As we only have an instant launch window for this evening, it is not possible to go ahead with the launch and it is not possible to do anything other than come back tomorrow, same place, same time for the second attempt," Jean-Yves Le Gall, the chief executive officer of Arianespace said in announcing the scrub.
Lift-off delayed for European comet mission
KOUROU, French Guiana (AFP) Feb 26, 2004
European space officials on Thursday postponed the launch of the first-ever probe aimed at landing on the surface of a comet, putting off the lift-off for 24 hours due to high-altitude winds.
An Ariane 5 rocket had been due to lift off carrying the European spacecraft Rosetta, destined for a 10-year-mission to intercept the Churyumov-Gerasimenko, a cool 675 million kilometers (421 million miles) from the Sun.
The delay was announced by Mario de Lepine, spokesman for the Arianespace company which operates the Ariane rockets from the European space centre in Kourou, in France's south American territory of Guiana.
The "launch window" for the lift-off -- the period in which it is technically possible -- runs for 21 days from Thursday, officials said.
E non hanno detto il perchè del ritardo?
Originariamente inviato da gpc
E non hanno detto il perchè del ritardo?
putting off the lift-off for 24 hours due to high-altitude winds
I palloni meteorologici lanciati prima del lancio hanno evidentemente rilevato venti in quota oltre l'intensità massima consentita per la sicurezza del lancio.
Originariamente inviato da GioFX
I palloni meteorologici lanciati prima del lancio hanno evidentemente rilevato venti in quota oltre l'intensità massima consentita per la sicurezza del lancio.
Ehm, m'era sfuggita quella riga... :fagiano: :D
Flight 158 - February 26
Liftoff set for the morning of February 27
The countdown for Flight 158 resumed this afternoon with the prospect of more favorable weather conditions at the Spaceport in French Guiana for tomorrow's early morning liftoff.
A first launch attempt this morning was put on hold was due to wind conditions at altitude, which are part of the safety considerations of each Ariane launch.
Both the Ariane 5G and its Rosetta comet-intercept payload continue in a safe mode in the Spaceport's ELA-3 launch zone.
Due to Flight 158's unique mission profile with its Rosetta deep-space probe, the launch time is fixed for a precise instant: 50 seconds past 4:36 a.m. (local time at the Spaceport).
This is in contrast to typical Ariane missions with telecommunications satellites -- which usually have launch windows of minutes or hours, allowing more margins to wait out unfavorable weather conditions or other launch constraints.
After Flight 158's liftoff, the Rosetta spacecraft payload will be placed on an Earth escape trajectory that will lead to its encounter with Comet Churyumov-Gerasimenko in 2014.
Rocket trouble delays Rosetta until next week
BY JUSTIN RAY
SPACEFLIGHT NOW
Posted: February 27, 2004
Launch of Europe's ambitious Rosetta mission to orbit a comet and deliver a tiny lander onto the icy surface has been postponed yet again -- this time by insulating foam that detached from the Ariane 5 rocket's main stage.
http://spaceflightnow.com/ariane/v158/images/040227ariane5.jpg
The Ariane 5 rocket will launch Rosetta. Credit: ESA/CNES/Arianespace
Originally scheduled for blastoff in January 2003, Rosetta was grounded by concerns with the Ariane 5 in the wake of a failed launch and missed its window to reach comet Wirtanen.
After reprogramming the mission to target another comet, Thursday morning's initial launch attempt was thwarted by high-altitude wind conditions.
While preparing for another countdown Thursday evening, the foam trouble prompted officials to halt the launch. It is expected to be early next week before the next launch shot.
The rocket's main stage uses super-cold liquid hydrogen and liquid oxygen to feed the Vulcain 1 main engine during the first 10 minutes of flight. The stage is covered with insulation in a concept similar to the foam on space shuttle external tanks.
There is not yet a sense of urgency to launch Rosetta. The available period in which the craft can embark on its trek to comet Churyumov-Gerasimenko extends to March 17.
Rosetta will travel 10 years before arriving at its destination, becoming the first spacecraft to orbit a comet. A lander called Philae will separate from the Rosetta mothership and land on the comet's nucleus for detailed research.
Comets are believed to be time capsules holding important clues about the birth of the solar system and its early development. The Rosetta mission seeks to understand the properties of comets and the processes that take place inside them.
"Working in unison, the lander and the orbiter will revolutionize our understanding of comets," Rosetta project scientist Gerhard Schwehm said. "They will lead to amazing discoveries about the most primitive building blocks of the solar system."
che lancio sofferto... certo che, se il buon giorno si vede dal mattino, la missione non promette poi così bene...
Originariamente inviato da gpc
che lancio sofferto... certo che, se il buon giorno si vede dal mattino, la missione non promette poi così bene...
è normale, soprattutto con una missione come questa che non ha una finestra di lancio come tipicamente accade con i satelliti, di qualche minuto o ora, ma sono costretti a lanciare all'ora esatta, a 50 secondi dopo le 4:36, ora della Guaiana. Tuttavia non c'è fretta, dato che la finestra utile finisce il 17 marzo, meno rischi si corre, meglio è.
Rosetta's voyage to comet poised to launch tonight
BY JUSTIN RAY
SPACEFLIGHT NOW
Posted: March 1, 2004
Delayed several days to replace a patch of foam insulation on the Ariane 5 rocket, launch of the Rosetta comet probe has been rescheduled for early Tuesday.
http://spaceflightnow.com/ariane/v158/images/040301insulation.jpg
The missing piece of insulation is the tiny dark area on the main tank. It is located at the height of the two country flags that are below the letters 'ESA' on the solid rocket booster on the left. Credit: ESA/CNES/Arianespace
Liftoff from the Guiana Space Center in South America will occur at either 0717:44 GMT or 0737:44 GMT (2:17:44 or 2:37:44 a.m. EST) -- the two instantaneous launch times available Tuesday.
The first launch attempt last Thursday was scrubbed by unacceptable high-altitude wind conditions. Another try on Friday was called off after technicians discovered a piece of insulation had fallen off the Ariane 5's main stage. The material is needed to keep the super-cold fuels inside the stage at the proper temperature and prevent ice from forming on the rocket.
The workers found the insulation on the launch pad and traced it back to the rocket's side.
"The small piece (approximately 10 X 15 cm. in size) apparently separated as a result of temperature changes that occurred with the fueling and de-fueling of Ariane 5's cryogenic stage," Arianespace said in a statement. "The stage carries 155 metric tons of the cold cryogenic propellant (liquid oxygen/liquid hydrogen), and it was emptied after the first launch attempt was postponed on February 26 due to weather conditions."
"The situation is well identified and the repair is simple," Arianespace Chief Executive Officer Jean-Yves Le Gall said.
Plans called for the rocket to be returned to its assembly hangar so a new block of insulation could be attached over the weekend.
"Once the new piece is in place, the adhesive requires approximately 36 hours for its drying/curing process," Arianespace said.
The available window in which to launch Rosetta to comet Churyumov-Gerasimenko extends through March 17. The craft will travel through space for a decade before entering orbit around the comet and dispatching a tiny lander to its icy surface.
"I want to thank Arianespace for the decision to not take any risks with our mission," European Space Agency Director General Jean-Jacques Dordain said. "A few extra days on Earth for our 'baby' will have no consequence for this 10 year mission."
0658 GMT (1:58 a.m. EST)
The final minutes of the countdown are ticking at the Guiana Space Center for today's launch of the Rosetta spacecraft aboard the Ariane 5 rocket. Liftoff is scheduled for 0717:44 GMT.
0707:44 GMT (2:07:44 a.m. EST)
Minus-10 minutes and counting. The status panel in the Jupiter Control Center at Kourou remains green, indicating all remains in readiness for liftoff. The Ariane 5 is fueled, weather conditions are favorable and there are no troubles with the rocket, payload or ground support equipment.
0711 GMT (2:11 a.m. EST)
Minus-6 minutes, 30 seconds and counting. The Synchronized Sequence has started. Computers are now in control of this final segment of the launch countdown to prepare the rocket and ground systems for liftoff. There are two computers running the countdown -- one aboard the Ariane 5 and a redundant one at the ELA-3 launch complex.
0714:44 GMT (2:14:44 a.m. EST)
Minus-3 minutes. The scheduled launch time has been loaded into the rocket's main computer system. The main stage tank pressures should now be at flight level.
0715:44 GMT (2:15:44 a.m. EST)
Minus-2 minutes. The Vulcain 1 main engine supply valves are being opened. Also, the ground valves for engine chilldown are being closed.
0716:44 GMT (2:16:44 a.m. EST)
Minus-1 minute. A fast-paced series of events leading to launch will begin at Minus-37 seconds when the automated ignition sequence is started. The water suppression system at the launch pad will start at Minus-30 seconds. At Minus-22 seconds, overall control will be given to the onboard computer. The Vulcain main engine will be readied for ignition with hydrogen chilldown starting at Minus-18 seconds. The residual hydrogen burn flares will fire beneath the Vulcain engine at Minus-6 seconds to burn away any free hydrogen gas. At Minus-3 seconds, onboard systems take over and the two inertial guidance systems go to flight mode. Vulcain main engine ignition occurs at Minus-0 seconds with checkout between Plus+4 and 7 seconds. If there are no problems found, the solid rocket boosters are ignited at Plus+7.0 seconds for liftoff at Plus+7.3 seconds.
0717:04 GMT (2:17:04 a.m. EST)
Minus-40 seconds. The vehicle is now switching to internal power.
0717 GMT (2:17 a.m. EST)
LIFTOFF! The Rosetta spacecraft begins its journey to comet Churyumov-Gerasimenko aboard the Arianespace Ariane 5 rocket!
0728 GMT (2:28 a.m. EST)
Plus 11 minutes. The Ariane 5 rocket's main stage has completed its firing and separated. The upper stage and Rosetta have entered a long ballistic coast trajectory that will last nearly two hours before the upper stage ignites to propel Rosetta away from Earth.
0729 GMT (1:29 a.m. EST)
Plus+12 minutes. The upper stage and attached Rosetta spacecraft are presently on an arcing ballistic trajectory. They will travel about 3,800 km away from the planet before heading back toward Earth. Ignition of the upper stage occurs roughly 650 km in altitude. As the motor accelerates Rosetta, the duo will pass within 225 km of Earth before soaring away from our home planet.
0827:44 GMT (3:27:44 a.m. EST)
Plus+70 minutes. Today's flight of Ariane 5 is the first to use the A5G+ configuration distinguished by the new composite structure for the cylindrical vehicle equipment bay housing the rockets's guidance system and avionics and additional propellant in the upper stage.
The new bay structure decreases the mass by 100 kg but decreases the level of shock experienced during the in-flight separation between the rocket's main cryogenic stage and the upper stage. The bay is a cylinder that wraps around the upper stage.
The particular upper stage being used today is different from previous ones flown on earlier Ariane 5 mission. The hydrazine fuel tanks of the Storable Propellant Stage are larger, allowing 250 kg additional propellant to be carried. Also for this mission, the complete upper stage including all systems such as engine, tanks and feeder systems underwent specific testing and re-qualification.
Flight 158 - March 2
Liftoff of Ariane 5 and Rosetta![/SIZE]
Europe's unique Rosetta comet-intercept spacecraft has taken its first step on an 11-year mission following today's liftoff from the Spaceport aboard an Ariane 5 Generic launcher.
Flight 158's Vulcain main cryogenic engine ignited at 44 seconds past 4:17 a.m. (local time in French Guiana) - the first of two precise launch instances that were set for today's mission. This very specific timing was determined by the mission's unique profile.
After a standard ascent and initial flight profile, Ariane 5's EPS upper stage will enter a prolonged ballistic phase, followed by its delayed ignition at almost 2 hours after liftoff.
Rosetta will then be separated from the stage approximately 14 minutes later, embarking on an Earth escape trajectory that will lead to its encounter with Comet Churyumov-Gerasimenko in 2014.
Rosetta was developed in a European Space Agency-sponsored program and was built by an industrial team involving more than 50 contractors from 14 European countries and the United States.
The prime spacecraft contractor is Astrium Germany, and major subcontractors are Astrium UK (for the spacecraft platform), Astrium France (spacecraft avionics) and Alenia Spazio (assembly, integration and verification).
0857 GMT (3:57 a.m. EST)
Plus+1 hour, 40 minutes. The upper stage with Rosetta continues in the ballistic coast. Ignition of the rocket stage is coming up in approximately 15 minutes.
0910 GMT (4:10 a.m. EST)
Plus+1 hour, 53 minutes. Altitude is 1,000 km, velocity is 7.2 km/sec. The arcing ballistic trajectory is bring the launcher and attached payload back toward Earth in advance of engine ignition.
0914 GMT (4:14 a.m. EST)
Plus+1 hour, 56 minutes, 45 seconds. Ignition! The upper stage of Ariane 5 -- called the Storable Propellant Stage -- has fired to life for its burn to boost Rosetta on its trek to the comet.
0915 GMT (4:15 a.m. EST)
Plus+1 hour, 58 minutes. Altitude is 540 km, velocity is 7.8 km/sec.
0930 GMT (4:30 a.m. EST)
Plus+2 hours, 12 minutes. The rocket and Rosetta have zoomed past their close approach to Earth. They are now powering away from the planet. Altitude is 773 km, velocity is 10.2 km/sec.
0931 GMT (4:31 a.m. EST)
Plus+2 hours, 13 minutes, 42 seconds. Burn complete! The Ariane 5 rocket's Storable Propellant Stage has finished firing its Aestus engine, concluding the powered phase of this morning's launch. The stage is now reorienting to prepare for deployment of Rosetta.
0932 GMT (4:32 a.m. EST)
Plus+2 hours, 15 minutes. SPACECRAFT SEPARATION! The European Space Agency's Rosetta spacecraft has been released from the Ariane 5 rocket following today's launch on a decade-long mission to explore comet Churyumov-Gerasimenko.
0936 GMT (4:36 a.m. EST)
"Bravo Ariane!" says Arianespace Chief Executive Officer Jean-Yves Le Gall from the mission control center as officials declare today's launch a success.
0939 GMT (4:39 a.m. EST)
European Space Agency Director General Jean-Jacques Dordain reports that controllers are establishing contact with Rosetta.
Rosetta is in a looping solar orbit that will see it intercept Earth a year from now for a pivotal sling-shot fly-by, receiving a gravity assist on its trajectory to ultimately reach the comet. The craft will later fly past Mars and Earth in 2007 and Earth once again in 2009.
http://www.giornaletecnologico.it/scienza/200403/02/4043a8e9018d8/
Rosetta begins its 10-year journey to the origins of the Solar System
2 March 2004
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ESA PR 14-2004. Europe’s Rosetta cometary probe has been successfully launched into an orbit around the Sun, which will allow it to reach the comet 67P/Churyumov-Gerasimenko in 2014 after three flybys of the Earth and one of Mars. During this 10-year journey, the probe will pass close to at least one asteroid.
Rosetta is the first probe ever designed to enter orbit around a comet’s nucleus and release a lander onto its surface. For over a year it will conduct a thorough study of this remnant of the primitive nebula which gave birth to our Solar System about 5 billion years ago.
Rosetta’s mission began at 08:17 CET (07:17 GMT) on 2 March when a European Ariane 5 launch vehicle lifted off from the Guiana Space Centre, Europe’s spaceport in Kourou, French Guiana. The launcher successfully placed its upper stage and payload into an eccentric coast orbit (200 x 4000 km). About two hours later, at 10:14 CET (09:14 GMT), the upper stage ignited its own engine to reach an escape velocity in order to leave the Earth’s gravity field and enter heliocentric orbit. The Rosetta probe was released 18 minutes later.
“After the recent success of Mars Express, Europe is now heading to deep space with another fantastic mission. We will have to be patient, as the rendezvous with the comet will not take place until ten years from now, but I think it’s worth the wait” said ESA’s Director General Jean-Jacques Dordain witnessing the launch from Kourou.
ESA’s Operations Centre (ESOC) in Darmstadt, Germany, has established contact with the probe as it flies away from Earth at a relative speed of about 3.4 km/s. ESOC will be in charge of Rosetta operations and orbit determination throughout the mission. During the next eight months, the spacecraft’s onboard systems will be checked and its science payload will be commissioned. Then, it will be placed into hibernation mode for most of the ten years of its journey through the Solar System.
A 10-year odyssey
Rosetta will be reactivated for planetary flybys, which will be used to modify its trajectory through gravity assist manoeuvres, or asteroid flybys, observation of asteroids being one of the mission’s secondary objectives.
The first planetary encounter will be in March 2005, as Rosetta flies by the Earth for the first time. The gravity assist will boost Rosetta into an orbit that will take it to Mars two years later.
During its close encounter with Mars in February 2007, Rosetta will approach to a distance of about 200 km and conduct science observations. This Martian flyby will be followed by another Earth flyby in November the same year. Both planetary encounters will increase the probe’s orbital energy and boost it well into the asteroid belt.
A third and last flyby of the Earth in November 2009 will send Rosetta toward the orbit of comet Churyumov-Gerasimenko.
Then, by mid-2011, when it is about 800 million km from the Sun, Rosetta will ignite its main engine for a major deep-space manoeuvre that will place it onto an interception trajectory with the comet, which will take nearly three years to be reached.
Rosetta will be reactivated for good in January 2014, as it enters a six-month approach phase, closing in slowly on the nucleus of comet Churyumov-Gerasimenko. The comet will then still be far from the Sun and its nucleus should be dormant.
Rendezvous with a comet
Like comet 46P/Wirtanen, which was the planned target for Rosetta until its launch was postponed in early 2003, comet 67P/Churyumov-Gerasimenko is one of the periodic comets that were “trapped” in the inner Solar System after they came too close to Jupiter. This comet was discovered in September 1969 at the Almaty Astrophysical Institute in Kazakhstan. It was detected by astronomer Klim Churyumov, from the University of Kiev, Ukraine, on pictures taken by his colleague Svetlana Gerasimenko, from the Institute of Astrophysics of Dushanbe, Tajikistan.
Study of its orbit shows that it was captured quite recently, after too close encounters with Jupiter in 1840 and 1959. The comet is now revolving around the Sun every 6.6 years on an elliptical orbit with a low inclination compared to that of the Earth. Its perihelion (the closest point of its orbit to the Sun) is located between the orbits of the Earth and Mars, while its aphelion (the farthest point) is beyond Jupiter. In preparation for Rosetta’s mission, the comet’s nucleus was observed by the Hubble Space Telescope, which revealed an irregular body about 4 km in diameter. Being a relatively “fresh” comet in the inner Solar System, 67P/Churyumov-Gerasimenko is a promising target for the study of primitive Solar System material.
Rosetta will enter an orbit about 25 km above the nucleus in August 2014. It will then conduct detailed mapping of its surface and a landing site will be selected for Philae, its 100 kg lander. Philae will be dropped from an altitude of about 1000 meters and, due to the tiny gravity of the nucleus, it will touch down at walking speed. The lander will even have to anchor itself to the surface with a harpoon to avoid bouncing back. Philae will operate from the surface for at least a week, sending back very high resolution pictures and as information about the upper crust of the nucleus. These data will be relayed to Earth by the orbiter.
Rosetta will continue its observations of the comet’s nucleus for over a year, at least until December 2015, and will have a ringside seat to monitor the « awakening » of the comet’s activity as it comes closer to the Sun and reached its perihelion, in October 2015.
Probing the comet
The Rosetta probe was built for ESA by an industrial team of over 50 European companies led by EADS Astrium. It is a 3 tonne spacecraft with solar arrays spanning an impressive 32 metres. This is the first probe designed to travel beyond the orbit of Mars to rely on solar cells for its power supply. In addition to the Philae lander, Rosetta incorporates a 165 kg science payload consisting of 11 instruments developed in partnership by ESA member countries, the United States, Greece, Hungary and Taiwan.
Four of these instruments are dedicated to observation of the nucleus: the ALICE ultraviolet spectrometer, the OSIRIS high-resolution camera, the VIRTIS imaging spectrometer and the MIRO microwave radiometer/spectrometer. Three more instruments will study the composition of the nucleus and its emanations; the COSIMA and ROSINA spectrometers and the MIDAS microscope. The GIADA collector will analyse dusts in the vicinity of the nucleus while the RPC group of sensors will characterise the internal structure of the comet’s coma and its interaction with the solar wind. The last two instruments, CONSERT and RSI, will use radio waves, one to probe the internal structure of the nucleus and the other to determine the distribution of masses inside the nucleus and the structure of the coma.
The Philae lander, developed under the leadership of Germany’s DLR aerospace research agency, carries 9 instruments provided by ESA member countries in partnership with the United States, Hungary, Poland and Russia. Among these, the ÇIVA/ROLIS set of cameras will provide panoramic and stereoscopic high-resolution views. The APXS, COSAC and Ptolemy instruments will analyse soil compounds. The SESAME seismometer will probe the surface to a depth of 2 m, while its characteristics will be studied by the MUPUS instrument with sensors on the anchoring harpoon. The ROMAP magnetometer and a second model of the CONSERT experiment will study the magnetic field and its interactions with the solar wind.
The Rosetta Stone -unearthed in Egypt more than 200 years ago– gave XIXth-century Egyptologists the keys to decipher hieroglyphic writing and to rediscover three millennia of forgotten Egyptian history and culture and in-depth study of a comet’s nucleus and asteroids by the Rosetta probe is expected to enable today’s science community to decipher the mystery of the origins of our Solar System and to better understand the mechanisms ruling the formation of planetary systems around other stars.
Rosetta soars on ambitious comet intercept mission
BY STEPHEN CLARK AND JUSTIN RAY
SPACEFLIGHT NOW
Posted: March 2, 2004
Embarking on its epic voyage to gain new insights into comets and the history of our solar system, the Rosetta spacecraft was successfully launched today to rendezvous with a cosmic snowball and deploy a tiny lander onto its icy heart.
The Ariane 5 rocket fired up at 0717:44 GMT (2:17:44 a.m. EST), exactly when the booster could place the probe on the first leg of its ten-year course to comet Churyumov-Gerasimenko.
The Ariane solid rockets and first stage put Rosetta on an arcing suborbital ballistic trajectory about ten minutes after launch. The upper stage's Aestus engine fired nearly two hours after liftoff to send the 6,700-pound craft out of Earth's grasp and into solar orbit.
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The Ariane 5 rocket sent Rosetta on its comet adventure today. Credit: ESA/CNES/Arianespace
Rosetta aims to give scientists a wealth of knowledge about comets, frozen time capsules from billions of years ago, while helping the public at large wrestle some of the most fundamental questions that humans can ask.
"I think it is very hard to imagine that you don't wonder sometimes what is it all about? Where did it all come from?" says European Space Agency science director David Southwood. "Once we were all star dust. How did we turn out to be the complicated beings that we are now? I think we are looking for some of the clues that will help us put that story together."
Today's launch has been in the works since the Rosetta project began in 1993. Since then, the Rosetta team has been thrown a number of curves -- most recently the decision to delay the launch from January 2003 due to concerns with the reliability of the Ariane 5 rocket.
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An artist's concept shows Rosetta and its looping route to the comet. Credit: EADS Astrium
Delaying the launch from 2003 to 2004 caused managers to change targets for the probe, which required extensive studies of Churyumov-Gerasimenko to see if it was suitable to approach with a $1 billion spacecraft and safe to land upon with a tiny robot explorer.
Rosetta will take a circuitous route through the solar system and will arrive back in the vicinity of Earth next March for its first crucial gravity assist fly-by. The probe will reach Mars in March 2007, followed by two additional close approaches of Earth to tweak its course toward Churyumov-Gerasimenko.
Heading further from the Sun and past the asteroid belt, Rosetta will fly near several of these space rocks and study them from a distance of over a thousand miles before entering a hibernation period in mid-2011.
"These brief encounters are a scientific opportunity and also a chance to test Rosetta's instrument payload," explained Rosetta project scientist Gerhard Schwehm from the European Space Agency.
For two-and-a-half years, Rosetta's systems will be completely shutdown with the exception of its primary computer and radio receivers in order to conserve power. Fitted with two solar wings spanning almost 100 feet, the spacecraft will be the first to fly near the orbit of Jupiter and rely entirely on solar power.
"To provide the probe with the power it needs in space, we have given it the biggest solar panels ever carried by a European satellite," said Manfred Warhaut, Rosetta's operations manager.
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An artist's concept shows the Rosetta orbiter and its lander. Credit: EADS Astrium
Rosetta will also undergo a number of other extended periods of inactivity between key mission events during the journey to Churyumov-Gerasimenko to relieve manpower and electrical constraints.
Power production is strained for Rosetta because it will be traveling over 500 million miles from the Sun, where light levels are only four percent of those found on Earth.
Controllers will bring Rosetta back to life in early 2014 for a thruster firing to slow the probe's approach to the comet before entering orbit and beginning its mapping and scientific mission to characterize the surface.
"Rosetta carries more instruments than any previous scientific spacecraft -- that makes it challenging and one of the most exciting missions ever," said Claudia Alexander, U.S. project scientist for the mission from NASA's Jet Propulsion Laboratory. "We anticipate major discoveries, just like Galileo and Cassini."
By the end of the summer in 2014, Rosetta will be in orbit around Churyumov-Gerasimenko and science operations should be in full swing. A major priority will be the determination of favorable landing sites for a small 220-pound lander carried aboard Rosetta named Philae.
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Technicians work on the lander during pre-flight activities. Credit: EADS Space
The three-legged Philae will touch down on the surface in November 2014, firing a harpoon to keep the tiny craft anchored on the comet so it doesn't float away in the weak gravitational field. It will snap high-resolution pictures and acquire data about the comet's organic crust and molecules for transmission up to the orbiter for later relay to Earth.
Operating at least one week, perhaps significantly longer, Philae's instrument suite even includes a tiny drill that can bore a few inches into the comet for subsurface investigations.
Together the orbiter and lander will observe the traits and changes the comet goes through as it approaches the Sun. Officially, the mission is slated to come to conclude in late 2015.
"This will be our first ever chance to be there, first hand, so to speak, as a comet comes to life," Schwehm said. "As we will be accompanying Churyumov-Gerasimenko for two years, until the comet reaches its closest point to the Sun and travels away from it, we can at long last hope to acquire new knowledge about comets."
Comet Churyumov-Gerasimenko was discovered in 1969 and is considered a dusty comet that is roughly two by three miles in diameter. The Hubble Space Telescope was chartered to observe the comet for 21 hours in March 2003 to gather more specific details about Churyumov-Gerasimenko to allow project officials to decide whether to pursue it as a potential target.
"This comet has only about three-hundred-thousandths the gravity of Earth," said Alexander. "The Rosetta spacecraft will be able to make observations from as close as 2 kilometers (1.2 miles). The data from our state-of-the-art instruments will be amazing."
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An artist's concept of the Rosetta orbiter and its tiny lander nearing the comet. Credit: ESA/AOES Medialab
Scientists believe comets are made of the very same primitive materials that were present when the Sun and the solar system were formed an estimated 4.6 billion years ago.
Comets are balls of ice and rock believed to be formed far beyond the orbit of Pluto where conditions are cold and dark, much like they were as the solar system was born. Some of these objects are drawn toward the inner solar system and they become comets -- giving us a unique view of almost the same primordial materials that played such important roles in the formation of the Sun and the planets.
"They are the keys to understanding the way the whole solar system, the Earth, and how even we came into being. And with Rosetta we will be able to observe, study and analyze this primordial material up close for more than a year," said Paul Weissman of NASA's Jet Propulsion Laboratory.
"We are confident we will come a step nearer to understanding the origins and formation of our solar system and the emergence of life on Earth," said Schwehm.
Rosetta gets its name from the stone tablet found by French soldiers in Egypt in 1799 that contained the key to deciphering Egyptian hieroglyphics. Scientists hope this mission may unveil the mysteries surrounding how our planet and life came to be as we know it today.
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The Rosetta spacecraft is illustrated in this artist's concept. Credit: EADS Astrium
ESA managers are not lost on the difficulties associated with the mission.
"Rosetta is one of the most challenging missions undertaken so far. No one has ever attempted such a mission, unique for its scientific implications as well as for its complex and spectacular interplanetary space maneuvers," Southwood said.
"This mission will turn science fiction into science fact. Every aspect of comet Churyumov-Gerasimenko will be analyzed, resulting in the most comprehensive set of scientific measurements ever obtained of a comet," said Professor Ian Halliday, chief executive of the Particle Physics and Astronomy Research Council, which funded two of the instruments.
All systems GO for Rosetta
2 March 2004
Mission control for Rosetta has reported that the spacecraft's solar arrays were deployed at 10:54 CET and that the star-trackers' check was completed successfully at 12:30 CET.
ESOC Control Room flight director Alan Smith reported that at 10:54, Rosetta's solar array was deployed on target, two hours and 38 minutes after launch. At 11:12, 'Sun Acquisition Mode' was achieved. This means that Rosetta can now use the Sun as its source of power on its way to Comet 67P/Churyumov-Gerasimenko.
At 12:30, the star-trackers' check was completed and they were switched on. Rosetta uses star trackers to help fix its position and navigate its way to the comet.
Three of the four reaction wheels were switched on exactly as planned. These help to stabilise the spacecraft. The first orbit estimation of Rosetta has been performed by the ESOC Flight Dynamics team. This orbit estimation is very close to what was expected.
The spacecraft is stable and all systems are working well.
qualcosa in italiano, per solleticare un pò la curiosità.
BERNA - Tutto bene per Rosetta. La sonda spaziale europea, partita stamattina a bordo di un razzo Ariane 5 dal poligono di Kourou nella Guyana francese, ha aperto i pannelli solari e imboccato la traiettoria per il suo lungo viaggio - 5 miliardi di km - verso la cometa 67P/Churyumov-Gerasimenko. Una volta raggiunto l´obiettivo, la sonda atterrerà sulla cometa: è la prima volta che si tenta un esperimento simile.
La sonda è stata realizzata per studiare la composizione del nucleo della cometa. Per la sua realizzazione sono stati investiti circa 700 milioni di euro. La Confederazione vi ha partecipato con circa 26 milioni, dotando la missione di molte apparecchiature importanti.
Fra queste uno spettrometro di massa a doppia messa fuoco, uno spettrometro per il tempo di volo e un sensore per la pressione dei gas, con i quali si può esaminare la composizione della cometa. Di produzione elvetica sono anche minicamere, obiettivi grandangolari per fotografare all´esterno, nonché l´antenna più importante della sonda, quella che mantiene i collegamenti con la terra. Le apparecchiature concepite dall´Istituto di fisica di Berna.
La sonda ha la forma di un parallelepipedo di tre metri per due e una massa di 2905 kg; l´alimentazione elettrica è fornita da due pannelli solari che, una volta dispiegati, avranno una apertura di 65metri, quanto un campo di pallacanestro. Il lander ha una massa di 100 kg, di cui 27 kg di strumenti.
(fonte: ATS)
Rosetta inizia il suo viaggio lungo 10 anni verso le origini del Sistema solare
2 Marzo 2004
ESA PR 14-2004. Rosetta, la sonda europea per le studio delle comete, è stata lanciata con successo in orbita attorno al Sole; da questa posizione potrà raggiungere la cometa 67P/Churyumov-Gerasimenko nel 2014, dopo tre passaggi attorno alla Terra e uno attorno a Marte. Durante questi 10 anni di viaggio la sonda passerà accanto ad almeno un asteroide.
Rosetta è la prima sonda mai progettata a entrare in orbita attorno al nucleo di una cometa e a rilasciare un lander sulla sua superficie. Per oltre un anno condurrà uno studio approfondito di questi resti della nebulosa primitiva che ha dato origine al nostro Sistema solare circa 5 miliardi di anni fa.
La missione Rosetta è iniziata alle 08.17 CET (07.17 GMT) del 2 marzo quando un veicolo di lancio europeo Ariane 5 si è staccato dal suolo del Centro Spaziale della Guyana, lo spazioporto europeo a Kourou, Guyana francese. Il vettore è riuscito a posizionare il suo stadio più elevato e il carico utile che trasportava in un’orbita eccentrica senza propulsione (200 x 4000 km). Circa due ore dopo, alle 10.14 CET (9.14 GMT), lo stadio superiore ha acceso il proprio motore per raggiungere una velocità di fuga che gli consentisse di lasciare il campo di gravità della Terra ed entrare in un’orbita eliocentrica. La sonda Rosetta è stata rilasciata 18 minuti più tardi.
“Dopo il recente successo di Mars Express, l’Europa si dirige ora verso lo spazio profondo con un’altra fantastica missione. Dovremo essere pazienti poiché l’appuntamento con la cometa non avrà luogo che tra dieci anni ma credo valga la pena di aspettare” ha dichiarato Jean-Jacques Dordain, Direttore Generale dell'ESA, dopo aver assistito al lancio da Kourou.
Il Centro di Controllo dell’ESA (ESOC) a Darmstadt in Germania ha stabilito i contatti con la sonda mentre si stava allontanando dalla Terra a una velocità relativa di circa 3,4 km/s. Il Centro ESOC sarà responsabile delle attività di Rosetta e della definizione dell’orbita per tutta la durata della missione. Durante i prossimi otto mesi verranno tenuti sotto controllo i sistemi a bordo del veicolo spaziale mentre verrà collaudato il suo carico utile. Poi, verrà posta in ibernazione per la maggior parte dei dieci anni del suo viaggio attraverso il Sistema solare.
Un’odissea di 10 anni
Rosetta verrà riattivata in corrispondenza dei passaggi planetari, che saranno sfruttati per modificare la sua traiettoria tramite manovre a effetto fionda, oppure in corrispondenza dei passaggi di asteroidi, dato che la loro osservazione è uno degli obiettivi secondari della missione.
Il primo incontro planetario è previsto per marzo 2005 mentre Rosetta sarà in orbita intorno alla Terra per la prima volta. La manovra a effetto fionda lancerà Rosetta in un’orbita che le permetterà di raggiungere Marte due anni più tardi.
Durante il suo incontro ravvicinato con Marte a febbraio del 2007, Rosetta si avvicinerà a una distanza di circa 200 km ed effettuerà osservazioni scientifiche. Questo passaggio marziano sarà seguito da un altro terrestre a novembre dello stesso anno. Entrambi gli incontri planetari incrementeranno l’energia orbitale della sonda e la accelereranno nella cintura degli asteroidi.
Un terzo e ultimo passaggio intorno alla Terra a novembre 2009 invierà Rosetta verso l’orbita della cometa Churyumov-Gerasimenko.
Poi, a metà del 2011, quando si troverà a circa 800 milioni di km dal Sole, Rosetta accenderà il suo motore primario per un’importante manovra nello spazio profondo che la posizionerà su di una traiettoria di intercettazione della cometa che verrà raggiunta dopo tre anni.
La sonda verrà riattivata a gennaio inoltrato del 2014, quando entrerà in una fase di avvicinamento di sei mesi, avvicinandosi lentamente al nucleo della cometa Churyumov-Gerasimenko. La cometa sarà ancora lontana dal Sole e il suo nucleo dovrebbe essere quiescente.
Incontro con una cometa
Come la cometa 46P/Wirtanen, che è stato l’obiettivo programmato per Rosetta fino alla posticipazione del suo lancio all’inizio del 2003, la cometa 67P/Churyumov-Gerasimenko è una delle comete periodiche che sono state “intrappolate” nella parte interna del Sistema solare dopo essere giunte troppo vicino a Giove. Questa cometa è stata scoperta nel settembre del 1969, all’Istituto di Astrofisica di Almaty, in Kazakhstan dall’astronomo Klim Churyumov, dell’Università di Kiev, Ucraina, sulla base delle fotografie scattate dalla sua collega, Svetlana Gerasimenko, dell’Istituto di Astrofisica di Dushanbe, in Tagikistan.
Lo studio della sua orbita rivela che è stata catturata piuttosto di recente, dopo incontri troppo ravvicinati con Giove nel 1840 e nel 1959. La cometa ora sta compiendo la rivoluzione intorno al Sole ogni 6,6 anni, percorrendo un’orbita ellittica con un’inclinazione bassa rispetto a quella della Terra. Il suo perielio (il punto dell’orbita più vicino al Sole) si trova tra le orbite della Terra e di Marte, mentre il suo afelio (il punto più lontano) si trova oltre Giove. In preparazione alla missione Rosetta, il nucleo della cometa è stato osservato con il telescopio spaziale Hubble, che ha rivelato un corpo irregolare con un diametro di circa 4 km. Dato che si tratta di una cometa relativamente “fresca” nella parte interna del Sistema solare, 67P/Churyumov-Gerasimenko è un obiettivo promettente per lo studio del materiale primitivo del Sistema solare.
Rosetta entrerà in orbita a circa 25 km sopra il nucleo nell’agosto del 2014. Condurrà poi una mappatura dettagliata della sua superficie e verrà scelto un sito di atterraggio per Philae, il suo lander di 100 kg. Philae verrà rilasciato da un’altitudine di circa 1000 metri e, data la scarsa gravità del nucleo, toccherà il suolo alla velocità di una camminata. Il lander dovrà persino ancorarsi alla superficie con un arpione per evitare di rimbalzare. Philae sarà operativo sulla superficie per almeno una settimana, rinviando immagini a risoluzione molto elevata e informazioni sulla crosta superiore del nucleo. Questi dati verranno ritrasmessi alla Terra dall’orbiter.
Rosetta continuerà le sue osservazioni del nucleo della cometa per oltre un anno, almeno fino a dicembre 2015 e occuperà un posto in prima fila per monitorare il « risveglio » dell’attività della cometa man mano si avvicina al Sole e avrà raggiunto il suo perielio nell’ottobre 2015.
Sondare la cometa
La sonda Rosetta è stata costruita per l’ESA da un gruppo industriale costituito da oltre 50 aziende europee guidate da EADS Astrium. È un veicolo spaziale di 3 tonnellate con pannelli solari con un’imponente apertura di 32 metri. È la prima sonda progettata per viaggiare oltre l’orbita di Marte che basa la propria alimentazione sulle celle solari. Oltre al lander Philae, Rosetta trasporta un carico utile scientifico di 165 kg, costituito da 11 strumenti sviluppati in cooperazione dagli Stati membri dell’ESA, dagli Stati Uniti, la Grecia, l’Ungheria e Taiwan.
Quattro di questi strumenti sono dedicati all’osservazione del nucleo: lo spettrometro ultravioletto ALICE, la fotocamera ad alta risoluzione OSIRIS, lo spettrometro ad immagini VIRTIS e lo spettrometro/radiometro a microonde MIRO. Altri tre strumenti, gli spettrometri COSIMA e ROSINA e il microscopio MIDAS, studieranno la composizione del nucleo e le sue emanazioni. L’analizzatore GIADA esaminerà le polveri in prossimità del nucleo mentre il gruppo di sensori RPC studierà la struttura interna della chioma della cometa e la sua interazione con il vento solare. Gli ultimi due strumenti, CONSERT e RSI sfrutteranno le onde radio, uno per sondare la struttura interna del nucleo e l’altro per determinare la distribuzione delle masse all’interno del nucleo e la struttura della chioma.
Il lander Philae, sviluppato da DLR, l’agenzia di ricerca aerospaziali tedesca, leader del progetto, trasporta a sua volta 9 strumenti, forniti dagli Stati membri dell’ESA in collaborazione con gli Stati Uniti, l’Ungheria, la Polonia e la Russia. Tra loro il set di fotocamere ÇIVA/ROLIS riprenderà viste panoramiche e stereoscopiche ad alta risoluzione mentre gli strumenti APXS, COSAC e Ptolemy analizzeranno i componenti del suolo. Il sismometro SESAME sonderà la superficie a una profondità di 2 m mentre le sue caratteristiche verranno studiate dal MUPUS, lo strumento dotato di sensori posizionato sull’arpione di ancoraggio. Il magnetometro ROMAP e un secondo modello dell’esperimento CONSERT studieranno il campo magnetico e le sue interazioni con il vento solare.
La Stele di Rosetta, portata alla luce in Egitto oltre 200 anni fa, ha fornito agli egittologi del XIX secolo le chiavi per decifrare la scrittura geroglifica e riscoprire tre millenni di storia e cultura egiziane dimenticate, mentre è previsto che lo studio approfondito del nucleo di una cometa e di asteroidi da parte della sonda Rosetta permetterà alla comunità scientifica odierna di decifrare il mistero delle origini del nostro Sistema solare e comprendere meglio i meccanismi che regolano la formazione dei sistemi planetari intorno alle stelle.
MISSIONE TARGATA ITALIA
Tanta e qualificata la tecnologia italiana protagonista di una missione scientifica europea
Un fiore all'occhiello per la tecnologia italiana la missione Rosetta, la prima destinata ad orbitare attorno ad una cometa e a rilasciare un veicolo che studierà da vicino i segreti del suo nucleo, vero e proprio fossile del Sistema Solare.
"Ancora tanta tecnologia italiana protagonista di una missione scientifica europea", ha commentato l'amministratore delegato dell'Alenia Spazio, Maurizio Tucci. "Dopo il successo di Mars Express - ha rilevato - Rosetta ha a bordo tecnologie particolarmente sofisticate ed essenziali per i collegamenti tra la sonda e la Terra".
Alenia Spazio (Finmeccanica) ha contribuito alla missione con l'integrazione della sonda nei suoi stabilimenti torinesi e realizzando lo speciale trasponditore digitale di bordo, essenziale per i collegamenti tra la sonda e la Terra.
Capace di acquisire segnali debolissimi, il trasponditore è basato su un'architettura di elaborazione numerica dei segnali molto innovativa che costituisce, di fatto, la piattaforma di riferimento per tutte le missioni deep space.
"Le soluzioni sviluppate da Alenia Spazio per il trasponditore digitale di bordo - ha rilevato Tucci - consentono infatti la trasmissione e ricezione a Terra, ad elevatissima qualità, dei segnali di telemetria contenenti i dati scientifici prodotti dagli strumenti della missione.
Un lavoro altamente qualificato, quello dell'industria spaziale italiana - ha aggiunto - e frutto di una lunga acquisizione di know-how ed esperienza in uno dei pochi settori ad altissima tecnologia ancora presenti nel nostro Paese".
(ANSA)
The making of an Ariane 5 launch
http://www.esa.int/images/KOU01-182614-pih_L.jpg
3 March 2004
As Ariane 5 sped into space carrying Rosetta, it was easy to forget that behind this and every launch is a cast of hundreds. These people have been working for many months to prepare Europe’s Spaceport in Kourou, French Guiana, for these brief minutes of excitement.
Considering the hundreds of millions of kilometres that Rosetta will eventually travel to reach Comet 67P/Churyumov-Gerasimenko, it may at first seem strange that 99.8% of the propellant needed for the mission is consumed during the first hundred kilometres. This is because only in those first few minutes will the rocket be struggling both to slice a path through the atmosphere and to escape the pull of Earth’s gravity.
In order to make the day go smoothly, around 200 people have worked for months to bring three critical elements of the launch to readiness at the same time. The three elements are the rocket itself, known as the launch vehicle, the Rosetta spacecraft and the launch base.
Ariane 5 rockets are manufactured partly in Europe and partly in French Guiana. The European pieces are shipped to Kourou where the launcher is assembled with the locally manufactured elements. As soon as the hardware is ready and tested, the rocket’s flight software is loaded into its on-board computers so that it knows what to do!
As for the spacecraft itself, as soon as the tests are finished in Europe, it too is shipped out to Kourou for final assembly, testing and fuelling. It is then mounted to the launch vehicle using a special adaptor that will release it into space once the rocket has done its job.
One important part of the launch base is the meteorological station. It would be foolhardy to launch a rocket into a thunderstorm, as a lightning strike could seriously affect its electronics. Also, high winds at high altitude must be avoided. In the case of Rosetta, these winds indeed delayed the launch on 26 February 2004.
Another part of the launch base is made up of the tracking stations. Rosetta’s Ariane 5 soon passed out of range of the Galliot tracking station, near Kourou, and was followed in its journey around the world by stations in Brazil, Ascension Island, Kenya, Australia and Hawaii. n order to know what to expect on the day, all these places had rehearsed the launch during the preceding months.
Although every effort is made to minimise the risks, launches can still be dangerous. So on the day itself, all aircraft and ships are cleared from the immediate area. This is achieved using a standard, internationally applied procedure, also used to warn aircraft and shipping of military activities, accident sites and meteorological hazards.
The launch of Rosetta was a particular challenge as it was the first time Ariane 5 had placed a spacecraft onto an Earth-escape trajectory. To do this, an unprecedented delayed ignition of the Ariane 5 upper stage was needed. 106 minutes after Rosetta had been placed into space, the upper stage ignited and powered Rosetta away from the Earth towards its icy rendezvous.
The launch of any Ariane 5 is a grand symphony of human effort that reaches its unforgettable finale on the launch day itself. With Rosetta safely on its way, Europe’s Spaceport at Kourou now begins the whole process again in anticipation of its next, more standard, launch.
3 March 2004
The deployment of the high-gain antenna was successfully completed on 3 March at 03:23 CET. A test manoeuvre will be carried out at 12:45 CET to verify that all orbit and attitude control systems are working properly.
Frank1962
04-03-2004, 07:58
spero che non vorrete aggiornare questo thread per tutta la durata della missione! :D :D :D
Originariamente inviato da Frank1962
spero che non vorrete aggiornare questo thread per tutta la durata della missione! :D :D :D
:asd: :asd:
Rosetta's comet target seen from Earth telescope
EUROPEAN SOUTHERN OBSERVATORY NEWS RELEASE
Posted: March 3, 2004
Rosetta's comet target seen from Earth telescope
EUROPEAN SOUTHERN OBSERVATORY NEWS RELEASE
Posted: March 3, 2004
In the morning of March 2, the Rosetta spacecraft was launched on board an Ariane 5 launcher from the European Spaceport in Kourou, French Guiana. The European Space Agency (ESA) spacecraft will be the first to land on a comet.
Before the launch, and as a salute to their colleagues at ESA, astronomers used the New Technology Telescope at the European Southern Observatory (ESO) of La Silla in Chile to image Rosetta's target, Comet 67P/Churyumov-Gerasimenko, an approximately 4 kilometre size "dirty snowball" that orbits the Sun once every 6.6 years.
http://www.spaceflightnow.com/news/n0403/03comet/comet67p.jpg
A composite image of the nucleus of Comet 67P/Churyumov-Gerasimenko (the point of light at the center), recorded on February 26, 2004, at 6:15 UT with the SUSI-2 camera on the 3.5-m New Technology Telescope. It is based on fifteen series of exposures seen in three different wavebands and since the images were aligned on the comet, the images of stars in the field are trailed. The fact that the image of the comet's 'dirty snowball' nucleus is almost star-like indicates that it is surrounded by a very small amount of gas or dust. The distance to the comet from the Earth was approx. 600 million km. Credit: ESO
These new images show the object at a distance of approximately 670 million kilometres from the Sun - 4.5 times the distance from the Earth to the Sun.
These observations provide further confirmation that at this distance the activity on 67P/Churyumov-Gerasimenko is very low.
This is very good news for the mission, because it means that when Rosetta will meet in 2014 its target comet, at 790 million kilometres from the Sun, there will not be so much dust near the nucleus to hinder the landing.
Originally timed to begin about a year ago, Rosetta's journey had to be postponed. This delay meant that the original mission's target, Comet Wirtanen, which was observed two years ago by astronomers using ESO's Very Large Telescope could no longer be reached. Instead, a new target has been selected, Comet Churyumov-Gerasimenko.
The observations presented here are part of a continuous effort by astronomers to monitor Rosetta's target and provide the spacecraft controllers and the astronomers with very useful, regular updates, e.g., about the 'cometary weather' at the time of arrival.
http://www.spaceflightnow.com/news/n0403/03comet/comet67pmotion.jpg
The exposures have been combined to show the background objects in real colours. Because of its motion, the comet now appears as a trail. Credit: ESO
Originariamente inviato da Frank1962
spero che non vorrete aggiornare questo thread per tutta la durata della missione! :D :D :D
Come no? GioFX si è impegnato ufficialmente a fare un "Up" al giorno fino all'arrivo della sonda per tenere in vista il thread... :asd:
Originariamente inviato da gpc
Come no? GioFX si è impegnato ufficialmente a fare un "Up" al giorno fino all'arrivo della sonda per tenere in vista il thread... :asd:
:asd:
Il padre di un mio amico (iscritto al nostro forum come Bald0z ) ha lavorato in questo progetto,adesso lo informo di questo thread così magari da un suo contributo.
Originariamente inviato da Ser21
Il padre di un mio amico (iscritto al nostro forum come Bald0z ) ha lavorato in questo progetto,adesso lo informo di questo thread così magari da un suo contributo.
Alenia?
Originariamente inviato da Ser21
Il padre di un mio amico (iscritto al nostro forum come Bald0z ) ha lavorato in questo progetto,adesso lo informo di questo thread così magari da un suo contributo.
Vero :)
L'Italia (come ASI, Agenzia Spaziale Italiana) ha partecipato a Rosetta con l'SD2 (http://www.spazio.galileoavionica.com/B54_co.htm) di progettazione Tecnospazio S.p.A. (Galileo Avionica).
In pratica si tratta del "trapano" che effettuerà il buco sulla cometa per poi analizzarne i gas.
Alcuni dirigenti di Tecnospazio sono stati inviati alla sede dell'ESA nei Paesi Bassi per seguire da vicino le ultime fasi di preparazione prima del lancio.
Inoltre una collega di mio padre era a Kurou per assistere al lancio (in primavera 2003... poi rimandato a questa settimana).
Originariamente inviato da GioFX
Alenia?
Alenia si occupa di altro, comunque il gruppo è sempre Finmeccanica.
Originariamente inviato da baldoz
Vero :)
L'Italia (come ASI, Agenzia Spaziale Italiana) ha partecipato a Rosetta con l'SD2 (http://www.spazio.galileoavionica.com/B54_co.htm) di progettazione Tecnospazio S.p.A. (Galileo Avionica).
In pratica si tratta del "trapano" che effettuerà il buco sulla cometa per poi analizzarne i gas.
Alcuni dirigenti di Tecnospazio sono stati inviati alla sede dell'ESA nei Paesi Bassi per seguire da vicino le ultime fasi di preparazione prima del lancio.
Inoltre una collega di mio padre era a Kurou per assistere al lancio (in primavera 2003... poi rimandato a questa settimana).
M-I-T-I-C-O grazie x il contributo ;)
Originariamente inviato da baldoz
Alenia si occupa di altro, comunque il gruppo è sempre Finmeccanica.
Lo so, si è occupata dell'assemblaggio.
Thunder82
05-03-2004, 01:08
.
Thunder82
05-03-2004, 01:08
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Thunder82
05-03-2004, 01:08
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Thunder82
05-03-2004, 01:09
Sono contento che il lancio sia andato bene!
Io faccio Ing. Aerospaziale qui a Padova. La facoltà è stata istituita da 3 anni, per rendere omaggio al Grande "Bepi" Colombo, professore ormai deceduto 20 anni fa dell'università di Padova che ha dato importantissimi contributi alla NASA nel campo della propulsione e la gestione dei veicoli spaziali (talmente importanti che la NASA gli dedicherà una sonda mi pare, è la prima volta che chiamano una sonda col nome di una persona...).
Volevo anche dire che il CISAS di Padova (il cui presidente è il mio professore di misurazione e metrologia generale meccanica:D ) ha avuto un ruolo estremamente attivo nella progettazione della Wide Angle Camera a bordo di Rosetta (solo questa "videocamera" è costata la "sciocchezza" di 3,6 milioni di dollari...) ed ha anche progettato il PFS (Planetary Fourier Spectrometer) che era stato montato sulla nave madre di Beagle2 e che ha scoperto l'acqua ghiacciata al polo sud di Marte.
Inoltre l'università di padova sta eseguendo studi molto avanzati su impatti ad ipervelocità con detriti spaziali (di cui ormai le orbite sono piene) con un cannone a ipervelocità da 7km/s!
Questo per dire che l'Italia è in una posizione veramente di primo piano nella ricerca spaziale, e posso solo esserne contento visto che (spero) sarà il mio lavoro! :D
BUONA FORTUNA E BUON VIAGGIO ROSETTA!
Thunder82
05-03-2004, 01:12
ma che ha il forum stasera? mi ha fatto fare 5 post uguali...:rolleyes:
Thunder82
05-03-2004, 01:23
Ecco la wide angle camera montata su Rosetta
http://cisas.unipd.it/wac/cover.jpg
E il planetary fourier spectrometer su mars express:
http://cisas.unipd.it/images/pfs2.jpg
http://cisas.unipd.it/images/pfs4.jpg
:)
The Wide Angle Camera for the OSIRIS system of the cometary mission ROSETTA (P.I. of Osiris is Dr. U. Keller, MPAe) is characterized by an innovative two mirror optics (the primary being convex), large FoV (12x12 deg) and extremely clean PSF in order to detect faint gaseous features close to the bright cometary nucleus.
The scientific activity is done inside the Dept. of Astronomy (prof. C. Barbieri) and Astronomical Observatory.
The hardware activity (optical bench, thermal control, baffle, shutter, front cover, etc.), is supported by CISAS through the Depts. of Mechanical Engineering (Prof. F. Angrilli) and Electronics and Informatics (Prof. G. Tondello). Other collaborators are from the University of Venice (Prof. P.F. Brunello) for the baffle optical design.
The main scientific goals of OSIRIS as a whole were identified from the present large ignorance on the physical and chemical state of the surface of a cometary nucleus.
It is planned to obtain data on topography, morphology, layering, inner structure, number and location of active regions, rotation of the body, emission processes of dust and gases.
Erosion can be measured with images having resolution of 10 cm.
Global mapping at better than 1 m/px can determine the 3-D structure, density to better than 1% and moments of inertia (in cooperation with radio science).
For the dust, it is planned to obtain the column density just above the surface, and to detect its emission at large heliocentric distances. Structures in the dust coma could change over short time intervals, so images are needed with rapid repetition rates. Day/night effects can be detected observing eclipses in forward scattering.
Regarding cometary gases, the cancellation of the IR channel and of the UV capability had the consequence of preventing a large scientific body of investigations on the parent molecules (like water) from being carried out with OSIRIS. Therefore only daughter molecules will in general be followed near the nucleus surface and in the coma. High speed monitoring will be carried out also in the gas filters.
Secondary scientific targets of OSIRIS are the two asteroids that will be encountered during the flight to the comet, at the moment Otawara and Siwa.
Specific Objectives for the WAC
Asteroids
The two target asteroids are (to be confirmed):
a) 4979 Otawara, H=14.3, encounter 10 July 2006, flyby velocity = 10.6 km/s,
Sun-asteroid-S/C angle at approach = 31 deg, distance to Sun at encounter = 1.7 AU (X=-0.8, Y=-1.7), distance to Earth at encounter = ..., minimum distance S/C - asteroid = 1000 km (TBC)
According to information provided by N.Thomas (30 Nov. 98), the centre coordinates of the background stellar field as seen by the S/C are: 14h00m, -22deg0'.
b) 140 Siwa, H=8.3, encounter 23 July 2008, flyby velocity = 17.0 km/s, Sun-asteroid-S/C angle at approach = 12 deg, distance to Sun at encounter = 2.6 AU (X=-2-6, Y=-1.0), distance to Earth at encounter = ..., minimum distance S/C - asteroid = 1000 km (TBC) According to N.Thomas (30 Nov.1998) the coordinates of the center stellar background as seen by the S/C are: 12h32m, -02deg00'.
The main scientific goals of WAC camera during asteroid fly-byes are:
to contribute to the astrometric studies, using the rich stellar background
to ascertain its environment, such as a possible satellite or dust coma
to characterize the body (size, shape, pole orientation, period of rotation, density) and surface (cratering and mineralogical composition) producing a multi-band albedo map
A satellite of an asteroid is expected (from dynamical and statistical considerations) to orbit within one or very few hundreds of the parent asteroid radius.
140 Siwa is a large asteroid, with a diameter estimatd from 115 to 150 km. Some authors (Schober and Stanzel 1979; Harris and Young 1980) give a rotation period of >22 h; Lagerqvist et al. (1992) estimate instead 18.5 h. Our group (see Barucci et al.,1998) has obtained 8 spectra of it. The tassonomic class is C.
4979 Otawara is small, 10 to 20 km, and essentially unknown.
Siwa then drives the requirements for the total field to be surveyed for a companion. In order to image a field of some 3.4x10^5 km with the 12 deg field of the WAC the first images must be taken from a distance of not more than 10^5 km: at that distance the resolution is of 10 km/px, and Siwa occupies on the CCD some 10x10px. Exposure times ranging from 10ms to 100ms can be utilized without incurring in saturation problems (to be refined). From this distance onward, the saturation will not change (constant surface brightness), but the asteroid will be increasingly resolved. In 100ms we obtain a good S/N ratio with 5th mag stars or brighter.
Regarding the surface characterization, at the expected approach distance of 1000 to 1500 km, the NAC FoV will image only part of the surface of Siwa (40x40 km to 60x60 km). Therefore we have to take images with both cameras.
Activities of the WAC Team:
a) Ground and Space Support: to collect images and spectra of the targets and of other similar asteroids to improve the knowledge of the main physical and mineralogical characteristics.
b) Modeling: we plan to model the shape and rotational state of the asteroid, using techniques such as photo-clinometry.
Cometary Physics: Our team plans to observe the comet during the entire mission.
Cometary Nucleus Main contributions of the WAC will be:
to help with recovery and astrometry in respect to the stellar background
to help to time the starting of cometary activity
to perform a global analysis to determine the overall shape, dimensions and rotational status.
to survey large scale features in order to identify the shape and number of the supposed cometary building blocks (whose sizes could range from 10m to 100 m, although most theories favour larger sizes from 100m to 600 m)
to contribute to produce a multi-band albedo map to determine global surface composition, texture, and porosity
to provide the reference frame for NAC images and Surface Science Package Roland landing site. Maximum exposure times of 100 msec during global mapping are set by smearing.
To provide mapping of large areas at very close distances, the WAC must stay in acceptable focus down to better than 1 km from the comet.
Dust Coma Main goals are:
to map the distribution of dust around the nucleus, to identify jets, streamers, etc.
to determine the dust production rate, dust size distribution and dust velocity (in conjunction with GIADA measurements).
According to current models, the dust particle velocity could range between 0.5 and 1 km/s, which is the gas drag velocity. However ISO data on comet Wirtanen give a much smaller velocity of 25 m/s for 0.1mm particles 120 days before perihelion. A better determination of this dust particle velocity will be greatly helped by the WAC images. In order to observe dust structures in the near vicinity of the surface, a very high contrast ratio is needed, at least 10^{-4} as the ratio between the nucleus and the dust features brightness. To reach this high contrast ratio is one of the main drivers for the WAC optical design.
Gas Coma
The WAC images will be used to determine the gas production rate, distribution and velocity. To perform this topic we need to collect images already during the approaching phase, at about 3.3 AU from the Sun; in this way it will be possible to detect the presence of activity (possibly even a fossil coma) at such large heliocentric distances, as for example of the CO and of other radicals.
During the approach to the Sun, the WAC will take images in the gaseous band filters, in particular of the OH, of the CS (in the near UV, where no other instrument can observe), and of the Na. The Giotto mission found a collisional coma of about 3000 km for the comet P/Halley; considering that comet P/Wirtanen is less active than P/Halley, we need to get images at a distances not lesser than 7000 km from the nucleus. The discovery of the Na tail on comet Hale-Bopp raised a great deal of attention on NA production and distribution. Different sources seem to at work, such as release of gases from the dust particles, molecular dissociations, release directly from the nucleus.
Activities of WAC group:
to model the nucleus adopting the photoclinometric method
to improve the hydro-dynamical model of the coma considering the physical and dynamical properties of the dust particles
to model the distribution of the gas around the nucleus and the active regions on the surface.
Ground Support:
photometric observations of the coma and of the dust tail of the comet P/Wirtanen and other short period comets (P < 20 years).
Mission Phases: Asteroid Fly-byes
a) Otawara. Given the small dimension of the asteroid, the NAC can perform most of the scientific goals. However the larger FoV of the WAC gives a richer stellar background.
b) Siwa. For the detection of the possible satellite the WAC needs to take images starting from at least 1x10^6 km, and many images are needed also during the closest passage (for instance the WAC could follow an immersion or emersion of the possible satellite). Furthermore, the WAC images will always cover the entire asteroid, and will place the NAC images in the proper perspective.
Mission Phases: Global mapping and close observation
During the global mapping and close observation phases, the WAC will take close images of the comet that will cover a large portion of the nucleus (at a distance of 5 km from the surface, the FOV of WAC is 1.5x1.5 km^2 while NAC will cover 210x210 m^2). The WAC images will represent a reference frame on which to position the high-resolution NAC images.
It is not possible to define a priori the exposure times without knowing:
1) the albedo of the comet nucleus surface
2) the parameters of the orbit around the comet
3) the spin of the nucleus. The occurrence of smearing put strict constraints on the maximum exposure time.
Mission Phases: Comet escort to perihelion (extended monitoring)
After the deployment of the SSP, the spacecraft will spend about 8 months in a safe orbit around the nucleus until the comet's perihelion passage. In this phase the scientific goals of WAC will be to monitor the nucleus activity and take high sensitivity images of the nucleus environment. At a distance between 30-50 km from the nucleus, the FOV of WAC will cover a region up to 8 cometary radii. A wide range of flux intensities will be met in following the comet during its approach to the sun. Variable exposure times are then needed, from a maximum of about 200 msec at the beginning of the monitoring phase when the comet is at about 3 AU from the sun, to a minimum of 50 msec close to the comet perihelion using the filters with lower transmission coefficient
Thunder82
05-03-2004, 01:26
per chi vuole vedere le fasi della costruzione della Wide Angle Camera:
http://cisas.unipd.it/wac/images.html
:)
Originariamente inviato da Thunder82
Sono contento che il lancio sia andato bene!
Io faccio Ing. Aerospaziale qui a Padova. La facoltà è stata istituita da 3 anni, per rendere omaggio al Grande "Bepi" Colombo, professore ormai deceduto 20 anni fa dell'università di Padova che ha dato importantissimi contributi alla NASA nel campo della propulsione e la gestione dei veicoli spaziali (talmente importanti che la NASA gli dedicherà una sonda mi pare, è la prima volta che chiamano una sonda col nome di una persona...).
La BepiColombo è una missione destinata a Mercurio dell'ESA in collaborazione con la giapponese Jaxa, non della NASA. ;)
Thunder82
05-03-2004, 10:29
Originariamente inviato da GioFX
La BepiColombo è una missione destinata a Mercurio dell'ESA in collaborazione con la giapponese Jaxa, non della NASA. ;)
Vabbè, ho solo sbagliato organizzazione:D
Fattosta che è la prima missione a prendere il nome da uno scienziato contemporaneo mi pare:)
Originariamente inviato da Thunder82
Fattosta che è la prima missione a prendere il nome da uno scienziato contemporaneo mi pare:)
In realtà c'era anche la missione, cancellata in novembre (per motivi di budget), Eddington. Cmq si, è una delle prime.
;)
A quanto ho saputo ci sono stati tagli di budget e il centro dell'ASI a Matera chiuderà... e così le partecipazioni dell'Italia alle missioni dell'ESA.
Un vero peccato!
Originariamente inviato da baldoz
A quanto ho saputo ci sono stati tagli di budget e il centro dell'ASI a Matera chiuderà... e così le partecipazioni dell'Italia alle missioni dell'ESA.
Un vero peccato!
Guarda, non credo che chiudere un centro implichi non partecipare più a missioni internazionali. ASI non partecipa solo tramite ESA, ma anche come soggetto indipentente in missioni ESA e NASA.
Two asteroid fly-bys for Rosetta
11 March 2004
ESA PR 15-2004. Today the Rosetta Science Working Team has made the final selection of the asteroids that Rosetta will observe at close quarters during its journey to Comet 67P/Churyumov-Gerasimenko. Steins and Lutetia lie in the asteroid belt between the orbits of Mars and Jupiter.
Rosetta's scientific goals always included the possibility of studying one or more asteroids from close range. However, only after Rosetta's launch and its insertion into interplanetary orbit could the ESA mission managers assess how much fuel was actually available for fly-bys. Information from the European Space Operations Centre (ESOC) in Germany enabled Rosetta's Science Working Team to select a pair of asteroids of high scientific interest, well within the fuel budget.
The selection of these two excellent targets was made possible by the high accuracy with which the Ariane 5 delivered the spacecraft into its orbit. This of course leaves sufficient fuel for the core part of the mission, orbiting Comet 67P/Churyumov-Gerasimenko for 17 months when Rosetta reaches its target in 2014.
Asteroids are primitive building blocks of the Solar System, left over from the time of its formation about 4600 million years ago. Only a few asteroids have so far been observed from nearby. They are very different in shape and size, ranging from a few kilometres to over 100 kilometres across, and in their composition.
The targets selected for Rosetta, Steins and Lutetia, have rather different properties. Steins is relatively small, with a diameter of a few kilometres, and will be visited by Rosetta on 5 September 2008 at a distance of just over 1700 kilometres. This encounter will take place at a relatively low speed of about 9 kilometres per second during Rosetta's first excursion into the asteroid belt.
Lutetia is a much bigger object, about 100 kilometres in diameter. Rosetta will pass within about 3000 kilometres on 10 July 2010 at a speed of 15 kilometres per second. This will be during Rosetta's second passage through the asteroid belt.
Rosetta will obtain spectacular images as it flies by these primordial rocks. Its onboard instruments will provide information on the mass and density of the asteroids, thus telling us more about their composition, and will also measure their subsurface temperature and look for gas and dust around them.
Rosetta began its journey just over a week ago, on 2 March, and is well on its way. Commissioning of its instruments has already started and is proceeding according to plan.
"Comets and asteroids are the building blocks of our Earth and the other planets in the Solar System. Rosetta will conduct the most thorough analysis so far of three of these objects," said Prof. David Southwood, Director of ESA’s Science Programme. "Rosetta will face lots of challenges during its 12-year journey, but the scientific insights that we will gain into the origin of the Solar System and, possibly, of life are more than rewarding."
Rosetta's scientific 'first' - observation of Comet Linear
26 May 2004
ESA PR 29-2004. ESA's comet-chaser Rosetta, whose 10-year journey to its final target Comet 67P/Churyumov-Gerasimenko started on 2 March, is well on its way. The first phase of commissioning is close to completion and Rosetta has successfully performed its first scientific activity - observation of Comet Linear.
The commissioning activities, which started a couple of days after launch, included the individual activation of all instruments on board the Rosetta orbiter and the Philae lander. This first check-out worked flawlessly and showed that the spacecraft and all instruments are functioning well and in excellent shape.
The commissioning tests also paved the way for Rosetta's first scientific activity: observation of Comet C/2002 T7 (LINEAR), which is currently travelling for the first and only time through the inner Solar System and offered Rosetta an excellent opportunity to make its first scientific observation.
On 30 April, the OSIRIS camera system, which was scheduled for commissioning on that date, took images of this unique cometary visitor. Later that day, three more instruments on board Rosetta (ALICE, MIRO and VIRTIS) were activated in parallel to take measurements of the comet. Although the parallel activation of the instruments was not planned until later in the year, the Rosetta team felt confident that this could be done without any risk because of the satisfactory progress of the overall testing.
The first data from the remote-sensing observations confirm the excellent performance of the instruments. The four instruments took images and spectra of Comet C/2002 T7 (LINEAR) to study its coma and tail in different wavelengths, from ultraviolet to microwave. Rosetta successfully measured the presence of water molecules in the tenuous atmosphere around the comet. Detailed analysis of the data will require the complete calibration of the instruments, which will take place in the coming months. The OSIRIS camera produced high-resolution images of Comet C/2002 T7 (LINEAR) from a distance of about 95 million kilometres. The image (above) showing a pronounced nucleus and a section of the tenuous tail extending over about 2 million kilometres was obtained by OSIRIS in blue light.
The successful observation of Comet Linear was a first positive test for Rosetta's ultimate goal, Comet 67P/Churyumov-Gerasimenko, which will be reached in 2014. Rosetta will be the first mission to undertake a long-term exploration of a comet at close quarters whilst accompanying it on its way towards the Sun.
The unprecedented in-depth study conducted by the Rosetta orbiter and its Philae lander will help scientists decipher the formation of our Solar System around 4600 million years ago and provide them with clues of how comets may have contributed to the beginning of life on Earth. In particular, the Philae lander, developed by a European consortium under the leadership of the German Aerospace Research Institute (DLR), will analyse the composition and structure of the comet's surface.
After Rosetta's first deep-space manoeuvres were carried out on 10 and 15 May with the highest accuracy, the first phase of commissioning is set to be completed in the first week of June. Rosetta will then go into a quiet ‘cruise mode’ until September, when the second phase of commissioning is scheduled to start. These activities, including the interference and pointing campaign, will last until December.
So the Rosetta spacecraft is well under way on its epic 10-year voyage, to do what has never before been attempted – orbiting and landing on a comet.
http://www.esa.int/images/imageL,44.jpg
Image of Comet C/2002 T7 (LINEAR) showing a pronounced nucleus and a section of the tenuous tail extending over about 2 million kilometres. It was obtained by the OSIRIS camera on board Rosetta in blue light from a distance of about 95 million kilometres on 30 April 2004.
European probe slings past Earth on long trip to comet
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: March 5, 2005
The one-year old Rosetta comet chaser made a return visit to Earth Friday, flying by the planet to receive a boost to begin the long process of eventually sending the spacecraft on a trajectory to intercept the comet Churyumov-Gerasimenko in 2014.
http://spaceflightnow.com/news/n0503/05rosetta/rosettamoon.jpg
While approaching Earth for the first of a series of fly-bys, Rosetta turned its navigation camera to the Moon, half lit by the Sun. This image was taken at 1510 GMT Friday when Rosetta was 265,997 miles from the surface of the Moon. Credits: European Space Agency, ESA/ESOC
Launched last March 2, Rosetta has now completed one revolution around the Sun in an orbit similar to that of Earth. Over the past year, European controllers have put the craft through a number of tests to verify the function of key systems and instruments, and no major problems were reported.
Rosetta made its closet approach to Earth at 2209 GMT (5:09 p.m. EST) as it passed 1900 kilometers above Mexico. The fly-by will send the spacecraft into a larger solar orbit that will take it past Mars for another one of these "sling-shot" gravity boost maneuvers in February 2007, followed by two more passes by Earth.
These planetary fly-by's save fuel that would otherwise have to be spent to propel the spacecraft toward its target comet.
Controllers switched on some of Rosetta's scientific instruments in advance of the close approach to carry out calibration measurements of the Earth and Moon. Navigation cameras were also successfully tracked the Moon during the fly-by to test their ability to track objects in space. These cameras will be responsible for the rendezvous with Churyumov-Gerasimenko and for tracking as the probe passes by a pair of asteroids later in the mission.
Rosetta also captured images of the Earth and Moon near the point of closest approach, but those pictures will likely not be available for a few more days.
The European Space Agency also sponsored a contest for amateur astronomers to take pictures of Rosetta as it passed close to Earth. It was expected that small telescopes could distinguish the craft's 100-foot solar panels, and possibly its high-gain antenna.
The fly-by also put Rosetta in position to be able to observe NASA's Deep Impact probe as it fires a small projectile into comet Tempel 1. The impact will reveal the comet's inner structure, and Rosetta will turn its instruments toward the comet to make additional observations.
Rosetta is planned to be the first spacecraft to rendezvous with and enter orbit around a comet. These primordial relics from the formation of the solar system are believed to harbor materials dating back as far as 4.5 billion years. Rosetta will also release a lander to explore the comet at the surface.
Bravo Gio, vedo che stai tenendo fede al tuo impegno... mi raccomando, continua per i prossimi anni a tenerci informati, eh, contiamo tutti su di te :sofico:
pegasoalatp
30-04-2006, 00:26
io c'ero.
:) :) :cool: :cool:
pegasoalatp
08-06-2006, 08:23
1 Summary of Activities
The reporting period covers three weeks of cruise, in which telemetry stored during solar conjunction was recovered and the spacecraft reconfigured to Near Sun Hibernation Mode (NSHM).
On 24th May the spacecraft entered Passive Cruise Mode, including transition to NSHM, telecommunications reconfiguration to MGA with low telemetry and telecommanding bit rates and configuration of all subsystems for the new spacecraft mode. This completed the activities related to entry in Passive Cruise Mode. Two more passes were taken on 25th and 26th May, to
confirm the correct behaviour of the new spacecraft mode. The spacecraft will remain in this low activity, low bit rate mode until the 26th July.
No payload operations were carried out in the reporting period. SREM was kept active in the background for the entire period, and configured for a lower data collection rate to cope with the reduced visibility periods and bitrates available during the incoming passive cruise period.
A total of 7 New Norcia passes of 8 hours commanding were taken during the reporting period.
TM/TC links with the OCC have been established for all passes.
NNO Pass
Date DOY Main Activity
808 16-May-06 136 Monitor pass - Solar Conjunction TM Recovered
809 17-May-06 137 Monitor pass - Prepare NSHMEntry
814 22-May-06 142 Monitor pass - Prepare NSHMEntry
815 23-May-06 143 NSHM Entry - TTC reconfigured to MGA-X, TM bit rate to 148 bps, TC bit rate to 250 bps
816 24-May-06 144 NSHM monitor pass
817 25-May-06 145 NSHM monitor pass
823 31-May-06 151 NSHM monitor pass
At the end of the reporting period (DOY 153) Rosetta was at 354.0 million Km from Earth (2.37 AU; one-way signal travel time was 18 min 58 sec). The distance to Sun was 209.8 million Km (1.40 AU).
2 Satellite Status
2.1 Platform
2.1.1 AOCS / RCS
The AOCS configuration at the end of the reporting period is (since DOY 144/2006, Near Sun
Hibernation Mode entry):
• AOCS in Near Sun Hibernation Mode / attitude control based on Thrusters
• Gyros: all IMPs OFF
• Reaction Wheels: all OFF
• Both ACMs ON
• Star Tracker A in use (since DOY 286/2005); STR B OFF. Both units with SW 2.8.
• Gyro-less estimator ON, gyro-stellar estimator OFF
• Auto-WOL Disabled (since DOY 137/2006).
On DOY 137/2006, the Auto-WOL function was disabled. This function had been kept enabled throughout the solar conjunction as a safety measure for the long periods without ground station contact.
The only reaction wheel offloading of the reporting period was executed on DOY 143/2006, over the New Norcia station. During this wheel off-loading, the wheels were commanded to low angular momentums, in preparation for their switch-off at Near Sun Hibernation Mode entry a few hours later.
On DOY 144/2006, the Near Sun Hibernation Mode entry activities were carried out as follows:
- Solar Array Repositioning
- Wheel Offloading to +-2.71Nms
- Reactivation of unused ACM
- Activation of gyroless estimator and transition to GLEP
- Update of the spacecraft inertia matrix
- Ephemeris update
The spacecraft dynamics at Near Sun Hibernation entry stabilised within the commanded deadband of 1 degree (half-cone) within 30 minutes from the transition as expected. The fuel consumption at entry was 11.11 g. The maximum angular rate at entry was below 0.00015 rd/s
(rate around the X axis). On DOY 146 the attitude control deadband was changed from 1 deg to 5 deg half-cone over the non-coverage period. It will be reduced over each weekly pass to improve the RF link conditions.
On DOY 144/2006, STR-A lost track. Within 4 seconds, the AOCS had successfully commanded the unit back into tracking mode. No indication of the cause for this tracking interruption could be found in telemetry.
The current GSEP guidance is set as follows (since DOY 130/2006):
Guidance flags: X Earth pointing, Y axis perp to SSCE, +Y South pointing
Earth direction bias: For Normal Mode: No bias (+X Earth pointing).
For SHM: bias of 20 degrees over +X in the X/Z plane
2.1.2 TT&C
The performance of the subsystem is nominal.
On DOY 137/2006, the S-band transmitter 2 and the S-band ranging transponder were switched off. These units had been activated from DOY 074/2006 to support radio-science measurements during the solar conjunction.
On DOY 143, the TTC subsystem was reconfigured to use the MGA-X for up- and downlink.
The TM bit rate was reduced to 148 bps and the TC bit rate to 250 bps to ensure positive link margins throughout the NSHM phase. This configuration is the baseline for Near Sun Hibernation, as the attitude deadband of up to 5 degrees in this mode prevent the use of the
High Gain Antenna.
The back-up transponder remains configured for S-band reception at 7.8 bps via LGA-F
Since the TTC subsystem is configured on MGA-X and low bit rates, the downlink signal has been extremely noisy when coherent, as shown in the figure below plotting the received signal Es/No on DOY 151/2006. The noisy part of the plot corresponds to periods where the signal
was coherent.
This behaviour has already occurred in flight: it is normally indicative of false transponder lock conditions on-board and clears after a few hours. However, this time, there is no indication of false lock conditions in the transponder telemetry and the behaviour persists. Two Cebreros
passes have been scheduled on DOY 157 and 158/2006 to possibly discriminate between ground station and spacecraft as the cause of this problem.
2.1.3 Thermal
The thermal behaviour of the spacecraft is nominal and stable. Its configuration is NSHM1 since DOY 144/2006.
As expected after Near Sun Hibernation Mode entry, the temperature of the spacecraft internal units, such as batteries, tanks, CDMUs, reaction wheels, has decreased by a few degrees.
Apart from this mode-related adjustment of the on-board temperatures, the spacecraft is slowly warming up as the Sun distance decreases.
2.1.4 Power
The subsystem is in its nominal configuration and performing nominally. All three batteries are in active configuration, at full state of charge.
2.1.5 Data handling
The subsystem is in its nominal hardware and software (v7) configuration. SSMM runs SW version 1.6 since DOY 159/2005.
On DOY 137, minor telemetry reconfigurations were performed in preparation for the upcoming Passive Cruise Mode phase. In particular, RPC events were re-routed from the default event packet store to the RPC event packet store to minimise the risk of an event packet store wraparound during the RPC observation of comet Honda, scheduled for beginning of July 2006 while
the spacecraft is in Passive Cruise Mode.
On the same day, the size of the packet store dedicated to Avionics dumps was increased to accommodate full SGM dumps performed outside coverage.
Systematic dumps of stored housekeeping telemetry were suspended at Near Sun Hibernation Mode entry on DOY 144. They will only be resumed after Near Sun Hibernation Mode exit on DOY 207. In the mean time, only stored events and acknowledgements packets will be retrieved by ground during each scheduled ground station pass.
On DOY 144, the SSMM dumps were started only for events and acknowledgement packets, but no VC1 frame was received for several hours. A housekeeping dump was finally commanded in addition to generate a continuous VC1 flow. This behavior is under investigation.
The TC Link Monitor timeout was set to 11 days (15840 min) on DOY 145.
2.1.6 Mechanisms
All mechanisms are performing nominally. On DOY 143, the solar arrays were commanded to
an optimum position and the Solar Array Drive Mechanism switched off at Near Sun Hibernation Mode entry. Apart from one ground commanded repositioning of the solar arrays on DOY 172, the Solar Array drive mechanism will remain off throughout the Near Sun Hibernation phase.
The HGA Pointing Mechanism is switched off and will remain off throughout the Near Sun Hibernation phase.
2.2 Payload
The only instrument operated in the reporting period was SREM.
SREM remains active in the background for radiation monitoring. SREM’s data collection rate was further reduced on DOY 142 to cope with the limited ground contacts during the near sunhibernation period.
3 Ground Facilities
3.1 Ground Stations
A total of 7 New Norcia passes were taken over the reporting period.
During the reporting period, several incidents at the New Norcia ground station caused temporary degradation of the service:
- On DOY 143, the High Power Amplifier (HPA) tripped off twice during the pass. After the second drop, the Low Power Amplifier was used instead of the HPA. Each time, a few frames were lost as the downlink signal went non-coherent. Also ranging data were lost due to the trip-off events.
- During the pass on DOY 143-144 (the first pass taken with Medium Gain Antenna and low bit rates), it was not possible to resolve ranging throughout the pass, despite several sweeps with HPA and LPA. Towards the end of the pass, ranging lock was finally achieved using the HPA with 21kWatts.
- Since the pass on DOY 143-144, large noise is being observed on the downlink signal when coherent. The noise is observed independently from the IFMS or Power Amplifier used. Cebreros passes are scheduled on DOY 157 and 158 to further investigate the problem.
- On DOY 152, the HPA suddenly stopped working during the pass. The unit was left down for investigation. A few frames were lost when the signal went non-coherent, and ranging data could not be acquired. This was due to a piece of hardware failing with the Power Amplifier. The problem was fixed during the next working day.
3.2 Control Centre
The RMCS supported all real-time activities successfully.
On DOY 150, the FTS was upgraded on ROMCA to support grouped POR delivery by RSOC.
Following this installation, at LOS on DOY 152, periodic errors were generated by the FARCgfts task on the server (ROMCA). The software support team immediately fixed the problem, which was due to the fact that the installed FTS is configured by default for MCS based on the new SCOS-2000 version 3.1 while ROMCA is still running SCOS version 2.4.
Testing of the new version of the RMCS software (v3.7), based on the Venus Express system and in turn on the new SCOS-2000 v.3.1, continued throughout the reporting period. This version, first installed on the E-chain (EQM Operations) on DOY 128, was installed on the Bchain
on DOY 136. Since then, spacecraft telemetry is routed to the B-chain in parallel to the Achain during all scheduled ground station passes. Furthermore, the spacecraft was successfully commanded from the B-chain on DOY 137. Migration of the A-chain is planned for the next reporting period.
4 Special Events
None
5 Anomalies
The following Anomaly Report was raised in the reporting period:
ROS_SC-111 Unexpected Behaviour of VC1 Dump at low TM Generation Rate and Bitrate
6 Future Milestones
The spacecraft will remain in Passive Cruise Mode until the 26th July 2006. In the entire period, the spacecraft will be monitored on the basis of weekly ground station passes.
Operations for the Mars swing-by (February 2007) will start in August 2006, with another payload passive checkout (PC3), an intense tracking campaign around the Trajectory Correction Manoeuvre (DSM-2) in September, and the first payload Active Checkout (PC4) in November/December.
ESA Press Release:
Rosetta correctly lined up for critical Mars swingby
15 February 2007
ESA mission controllers have confirmed Rosetta is on track for a critical 250-km Mars swingby on 25 February. Engineers have started final preparations for the delicate operation, which includes an eclipse, a signal blackout, precise navigation and complex ground tracking.
Rosetta is scheduled to make its closest approach to Mars at 02:57 CET on Sunday, 25 February, using the Red Planet as a gravitational brake to reduce speed and alter trajectory as part of the spacecraft's complex, 10-year, 7.1-thousand-million-kilometre journey to comet 67P/Churyumov-Gerasimenko.
"Last Friday's engine firing went well. On Tuesday, we confirmed the spacecraft is on nominal track for the swingby. There is currently no need for additional engine burns, so the next manoeuvre slot, planned for the weekend, has been cancelled," said Paolo Ferri, Rosetta Flight Director, speaking at ESOC, ESA's Space Operations Centre in Darmstadt, Germany.
Communications blackout, eclipse as Rosetta passes behind Mars
Later today, the Flight Control Team is scheduled to begin charging Rosetta's batteries for the planned 25-minute eclipse during the swingby. During the eclipse, Rosetta's solar panels will be shadowed from sunlight by Mars, and all but essential systems will be turned off or placed into low-power modes.
Rosetta's original trajectory and engineering design did not include an eclipse, but unavoidable launch delays forced the trajectory to be replanned. Mission controllers working on Rosetta have spent months carefully planning and testing a low-power configuration which will allow the spacecraft to safely operate on batteries.
Further, ground controllers expect to lose contact with Rosetta for a tense 15-minute occultation, or blackout, starting at 03:14 CET on 25 February, as Rosetta passes behind Mars with respect to ground stations on Earth.
At closest approach, Rosetta will skim by Mars in a spectacular passage, a mere 250 km above the Red Planet and travelling 36 191 km per hour relative to the planet. At this time, ESA's Mars Express will be some 11 042 kms away from Rosetta, while NASA's Mars Reconnaissance Orbiter will be about 7172 kms distant.
ESA-NASA cooperation for deep-space tracking
The intensive swing-by activities at ESOC have included a comprehensive tracking campaign to carefully plot Rosetta's position and trajectory.
Ranging and Doppler measurements from DSA 1, ESA's deep-space tracking station at New Norcia, Australia, have been augmented by data from NASA's DSN deep-space network. Both networks are using Delta DOR (Delta Differential One-Way Ranging) technology to precisely locate and track the spacecraft.
Delta DOR uses two widely separated ground antennas to simultaneously track a spacecraft and measure the time difference between signals arriving at the two stations. ESA first used the sophisticated technique to track Venus Express in 2006.
http://www.esa.int/SPECIALS/Rosetta/SEMKRCO2UXE_0.html
ESA Press Release
Media event at ESOC: closest encounter between ESA's comet chaser Rosetta and Mars
16 February 2007
ESA PR 08-2007. On Sunday 25 February, ESA’s probe Rosetta, currently on a ten-year journey to comet Churyumov-Gerasimenko, will make its closest approach to the planet Mars, coming within 250 kilometres of its surface.
The critical close swingby of Mars is needed to use the gravity of Mars to modify the spacecraft’s speed and direction. Rosetta will emerge from its martian encounter pointed towards its next target, Earth ! It arrives for a second swingby of our home planet on 13 November (the first having already taken place on 4 March 2005).
To take advantage of this upcoming closest of encounters with the Red Planet, Rosetta’s instruments - as well as those on its lander - will be switched on over predefined time slots to perform a series of scientific observations, including planetary imaging. Flight controllers at ESA’s European Space Operations Centre (ESOC) have already set everything ready for this crucial manoeuvre.
http://www.esa.int/SPECIALS/Rosetta/SEM5WDBE8YE_0.html
Da SpaceFlightNow.com:
Comet-bound probe enjoys close encounter with Mars
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: February 25, 2007
Europe's Rosetta comet probe shot past Mars early Sunday to line up for another swing by Earth later this year, putting the craft on course to reach its icy target in 2014.
Launched three years ago, Rosetta zoomed just 150 miles above the Martian surface at about 22,500 miles per hour relative to the Red Planet. The probe made its closest approach at 0215 GMT Sunday (9:15 p.m. EST Saturday) as it flew behind Mars and temporarily broke off communications with Earth.
http://www.spaceflightnow.com/news/n0702/25rosettamars/rosettamars.jpg
Stunning image taken by the CIVA imaging instrument on Rosetta's Philae lander just four minutes before closest approach at a distance of some 620 miles from Mars. A portion of the spacecraft and one of its solar arrays are visible in nice detail. Beneath, an area close to the Syrtis region is visible on the planet's disk. Credits: CIVA / Philae / ESA Rosetta
Download larger image version here (http://www.esa.int/images/CIVA_Mars_30_H.jpg)
Officials at the ESA Space Operations Center confirmed the speedy flyby was successful at 0257 GMT (9:57 p.m. EST Saturday) as telemetry from Rosetta began to again feed into the control room.
The Mars flyby created a slingshot-like effect for Rosetta, putting the spacecraft on a path to reach Earth on Nov. 13 for a similar maneuver.
"We actually use this flyby to slow down the spacecraft to optimize the Earth gravity assist," said Gerhard Schwehm, Rosetta project scientist.
Martian gravity was to have naturally slowed Rosetta by 4,900 miles per hour relative to the Sun, according to a European Space Agency statement.
Rosetta already completed a pass by Earth in 2005, and the craft will fly past Earth two more times later this year and in 2009 to set up for a rendezvous with comet 67P/Churyumov-Gerasimenko in early 2014.
By bouncing across the solar system to utilize natural gravity assistance, Rosetta saves precious fuel that would be necessary to send the probe on a direct route to its destination.
A suite of imaging instruments aboard Rosetta was commanded to observe the planet as the probe moved toward Mars, but the craft's payload systems had to be turned off about one hour prior to the flyby. Controllers were concerned Rosetta's batteries would be drained as the spacecraft passed behind Mars, which blocked the Sun's rays for about 25 minutes.
"Unfortunately, we will have to switch off the payload at closest approach as we will pass through an eclipse, a scenario Rosetta isn't built for," Schwehm said in an interview last week.
http://www.spaceflightnow.com/news/n0702/25rosettamars/mars.jpg
This image of Mars was taken by the OSIRIS narrow-angle camera on Saturday from a distance of about 150,000 miles, with an image resolution of about 5 km per pixel. Credits: ESA c 2007 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA
Download larger image version here (http://www.esa.int/images/MarsNACTwoColor_H.JPG)
In 2003, concerns with the reliability of the Ariane 5 rocket needed to launch Rosetta forced engineers to scrap the mission's original plan, and officials were forced to choose a backup comet for the spacecraft's new destination.
The changes meant Rosetta would be subjected to more hazardous conditions during its voyage, including an unplanned eclipse during its swing by Mars, according to ESA.
Rosetta's huge solar panels span nearly 100 feet tip-to-tip to gain efficiencies in power production in the outer solar system. The craft will be the first to fly beyond the asteroid belt and rely entirely on solar power.
Schwehm, also head of ESA's Solar System Science Operations Division, said Rosetta's primary optical and infrared camera could have achieved an image resolution of about 12 feet as the craft swooped in for its closest approach.
Despite the need to shut down Rosetta's powerful instruments, scientists still expected to get unique science opportunities from the flyby. The probe was to have downlinked the first ultraviolet measurements from near Mars, Schwehm said.
http://www.spaceflightnow.com/news/n0702/25rosettamars/marsatmosphere.jpg
Atmospheric structures can be seen in this image of Mars taken by the OSIRIS narrow-angle camera on Saturday from a distance of about 150,000 miles. Credits: ESA c 2007 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA
Download larger image version here (http://www.esa.int/images/mars_green_red_ratio3_H.JPG)
Rosetta's optical and infrared camera, ultraviolet imaging spectrometer, and visible and infrared thermal imaging spectrometer conducted about four hours of extensive observations of Mars late Saturday before being prepared for the dangerous eclipse period. A package of plasma sensors also worked to observe the environment around the Red Planet.
The instruments were turned back on to gather more data as Rosetta sped away from Mars Sunday.
The flyby was also the first opportunity for Rosetta's 220-pound lander to conduct independent science observations. Imaging systems and a plasma monitor were kept on during the eclipse because the lander has its own power system, according to an ESA statement.
The lander's camera captured spectacular images of Rosetta and Mars as the probe skimmed just above the planet's atmosphere.
Called Philae, the tiny craft will be dropped onto the nucleus of Churyumov-Gerasimenko in November 2014 for several weeks of experiments. Philae carries nine science instruments and a small drill to retrieve samples from below the comet's surface.
Rosetta will orbit Churyumov-Gerasimenko for more than a year of extensive science operations to observe the comet's changes as it approaches the Sun.
http://www.spaceflightnow.com/news/n0702/25rosettamars/
pegasoalatp
13-05-2008, 13:28
1 Summary of Activities
During the reporting period Rosetta successfully went through the second Earth Swing-by
manoeuvre that boosted the spacecraft towards a new and bigger orbit around the Sun. The
period was characterised by intense flight operations preceding and following the closest
approach that was on the 13th of November at 20:57:23 UTC when Rosetta flew at an altitude of
ca. 5300 km over the South Pacific.
No correction manoeuvres were needed in the days preceding the swing-by. Orbit
determination and manoeuvre optimisation performed after the swing-by confirmed the need for
a small correction. In order to optimise the fuel consumption the manoeuvre will be split in two
legs (one to be performed on the 23rd of November, the second in February 2008). See
annexes for further details.
Several instruments have been operating during the reporting period producing a significant
amount of science data, now being processed by the PI teams..
At the end of the reporting period (DOY 320) Rosetta was at 1.75 million km from Earth (0.011
AU); one-way signal travel time was 6 sec. The distance to Sun was 145.65 million km (0.98
AU).
2 Satellite Status
2.1 Platform
2.1.1 AOCS / RCS
The AOCS configuration at the end of the reporting period is:
• AOCS in NM / attitude control based on wheels since DoY 247.17.30/2007
• Gyros: IMP A (red) OFF (since DoY129/2007), IMP B (used) ON (since DoY
247.16.25/2007), IMP C (verif) ON (since DOY 283/2007).
• Reaction Wheels: all ON (A, C, D since DOY 247.16.55/2007, B since 248.15.55/2007),
B declared as isolated in the SW.
• ACM-A ON continuously, ACM-B ON continuously (since DOY 326/2006).
• Star Tracker B in use (since DOY 283/2007). STR A power cycled on DoY 129/2007;
STR B power cycled on DoY 114/2007. Both STRs are kept ON for anomaly
investigation.
• NAVCAM A and B OFF. Both cameras have been operated during the Earth Swing-by
phase. CAM-A was commanded to take 27 images of the Earth and the Moon in the
night of the swing-by, whereas CAM-B was commanded to take 9 images of the Earth
in the early hours of DoY 319.
All images have beensuccessfully acquired without observing the slow link with the SSMM.
• Gyro-stellar estimator ON since DoY 247/2007, gyro-less estimator OFF since DoY
247/2007.
• Auto-WOL Disabled (since DOY 137/2006).
• Deep Space flag set to TRUE (since DOY 298/2006)
• The SAS luminance threshold set to 20E-03 A since DoY 310.2007. It will be changed
back to the standard value in the next reporting period.
The current guidance options are set as follows (since DOY 310.09.30/2007):
NM/NSHM: X Sun pointing, Y axis perp to Ecliptic, +Y North pointing
Ref. axis [cos 35, 0, sin 35]
SHM: X Sun pointing, Y axis perp to Ecliptic, +Y North pointing
Ref. axis (MGA) [cos 35, 0, sin 35]
These guidance settings (same for NM and SHM) are required
to maintain the Sun in the +X/+Z quadrant and to point the
HGA to Earth in a phase where the Sun-SC-Earth angle is big
The entry in SHM was kept disabled on DoY 2007.316.13.15 till 318.21.00 to prevent the use of
the HGA in case of Safe Mode during high dynamics of the Earth-Sun-SC geometry.
2.1.2 TT&C
The performance of the subsystem is nominal. The subsystem has been reconfigured several
times during the reporting period due to the peculiarity of the Earth Swing-by phase:
• DoY 315.2007 the RF links have been switched to S-band via HGA/TRSP-2
• DoY 2007.316.13:00 the RF links have been switched to LGA-F/TRSP-2. During the
time when the spacecraft was on LGA the links had to be switched few times between
LGA-F and LGA-R due to the changing geometry and the planned attitude profile. On
DoY 319 the TM bit rate has also been reduced to 14 kbps to guarantee the proper
margin on the downlink signal.
The subsystem is configured for Active Cruise configuration since DOY 320.2007:
• TRSP-2 X-band up and down via HGA, 22 kbps downlink, 2kbps uplink.
• Back-up is now configured for S-band reception at 7.8 bps via LGA-R. This will be
changed in January 2008 when LGA-F will be visible again.
2.1.3 Thermal
The thermal behaviour of the spacecraft is nominal and stable. Since DoY 247/2007 the
subsystem is configured in Active Cruise Mode 1 for what concerns the heaters controlled by
hardware. The remaining part of the subsystem (controlled by SW) is configured for “close-to-
Sun” conditions since DoY 277/2007.
During the swing-by phase and the associated attitude profiles some effects have been noticed
on the thermal subsystem:
• TCT AP Line 15 Thruster 11 triggered on the high side declaring both LCLs failed (lines
13/14/16 were also declared as failed being on the same LCL). The triggering was due
to the Sun exposure of the bottom side of the SC for few hours. These lines were redeclared
safe on the prime LCL DoY 320 at the end of the planned attitude evolutions.
• TMT PL Line 14 RPC-IES triggered on the high side. Also this triggering is due to the
attitude manoeuvring for the science observations. There is no concern for the unit.
• Few temperatures are registered out of limit on the high side
The problems recorded so far were to be expected due to the reduced Sun distance and the
attitude profile but none of them is of particular concern so far.
2.1.4 Power
The subsystem is in its nominal configuration and performing nominally.
2.1.5 Data handling
The subsystem is in its nominal hardware and software (v7) configuration. SSMM runs SW
version 1.6 since DOY 159/2005.
The TC link monitor time-out is set to 4 days since DoY 310/2007.
The TM generation mode is “Routine mode” since DoY 247/2007.
The System Init Table (SIT) was updated in RAM and SGM on DoY 311 to select the LGA
options in case of survival mode. The MGA option will be selected again at the end of January
when the Sun-Spacecraft-Earth angle will go below 70 degrees.
2.1.6 Mechanisms
All mechanisms are performing nominally. The SADM is ON since DoY 248/2007 after exit from
NSHM. Due to the vicinity to the Sun, the APME is operated only when it is necessary to
reposition it for Earth pointing since DoY 283.2007. This strategy will be kept till the entry in
NSHM planned in February 2008.
2.2 Payload
During the reporting period some of the instruments have been operating as part of the Earth
Swing-by 2 observation campaign.
ALICE
The instrument has been operating during the swing-by from DoY 314.18.45. Few out of limits
have been recorded and are being analysed. None of them is of concern. The instrument will be
switched OFF on DoY 321.16.10.
CONSERT
Instrument is OFF.
COSIMA
Instrument is OFF.
GIADA
Instrument is OFF.
MIDAS
Instrument is OFF.
MIRO
The instrument is taking part to the swing-by campaign with several observations as from DoY
317.12.05. The MIRO operations will finish on DoY 322.12.15.
OSIRIS
The instrument was commanded to take several images of the Earth and the Moon during the
Earth Swing-by. Operations of the instrument went very smoothly as from activation on DoY
315.07.40. The instrument finished the ESB2 operations on DoY 320.11.50.
ROSINA
Instrument is ON (RTOF in stand-by) as part of an out-gassing attempt. The instrument was
powered down and up again when crossing the radiation belts on DoY 317. Since DoY
310.12.47 parameter NRNAR152 PSU_Temp_MCP_OS is out of limit (> 50 degC). The PI team
confirmed that this is of no concern for the current instrument configuration and that in this
configuration the detector can sustain a temperature of 150 degC.
RPC
The instrument has been operating since DoY 311.01.10 with MAG and LAP and will continue
till DoY 324..14.00. IES was activated between DoY 314.09.00 and 321.09.00, ICA was
activated between DoY 317.20.22 and 317.21.42. The MAG instrument stopped generating
science data on DoY 312 (SC AR 144). Power cycling of the instrument resolved the problem.
The anomaly is being investigated.
RSI
Instrument is in muted status. The Santiago ground station – owned and operated by University
of Chile – tracked Rosetta during the closest approach between 317.20.41 and 317.21.09 to
deliver Doppler measurement to the RSI PI team for scientific purposes.
VIRTIS
The instrument was operated during the swing-by as from DoY 317.16:54 registering few out of
limits which have been understood and are of not concern. An update of the limits in the DB is
expected. The instrument finished the ESB2 operations on DoY 319.00.55.
LANDER Philae
The ROMAP instrument was activated on DoY 311.00.00 and will be switched OFF on DoY
324.14.10.
SREM
Since DoY 248/2007 the accumulation settings are configured for active cruise mode.
4 Special Events
On DoY 317 at 20.57.22.964 UTC Rosetta flew at an altitude of 5294.852 km over the surface
of the Earth for its 2nd swing-by. Rosetta will swing-by again the Earth on the 13th of November
2009 for it s3rd and last swing-by on it sway to comet 67P Churyamov-Gerasimenko.
Few members of the Rosetta Mission Control Team at ESOC had the opportunity of seeing
their spacecraft approaching the Earth with a speed of ca. 40000 km/h. This was possible
thanks to the friends of the Strakeburg Sternwarte in Heppenheim (Germany). The images
below show Rosetta on the left of the red line on DoY 2007.316.22.00 and few minutes later.
Other amateur astronomers all over Europe could observe Rosetta thanks to the data provided
by the ESOC flight dynamics team and rewarded us with beautiful pictures of the spacecraft
crossing the winter sky. The pictures below were taken respectively from Italy (Italian CCAF
Circolo Culturale Astronomico di Farra ONLUS) and France (Marc Serrau).
The Rosetta Earth swing-by has also been characterised by warning and alarms regarding
potential hazards for the Earth coming from an asteroid that would fly only 5600 km over the
Earth surface in the night of the 13th of November. We were all very pleased to know that this
hazard was our spacecraft approaching the Earth and at the same time impressed by the
quality of the orbit determination of these alert centers.
In the night of the swing-by the mission control team at ESOC was also informed of an object
following Rosetta on a very similar orbit and coming from Mars (as Rosetta). Further analysis
revealed in this case that the object was an asteroid with an Apollo-type orbit (see Annex 5 for
an analysis of the trajectory of this object informally named “Son of Rosetta”).
All these events confirmed us once more that our spacecraft is actually flying the fantastic
adventure its was conceived for and it is not a simulator.
6 Future Milestones
The Earth Swing-by phase will continue now with the remaining payload operations and the first
trajectory correction manoeuvre planned for the 23rd of November. The intense navigation
campaign will finish shortly after.
The mission control teams are now planning check-out and tests in preparation of the Asteroid
fly-by of September 2008.
pegasoalatp
05-08-2008, 09:57
http://www.esa.int/esaCP/SEMF0B8N9JF_index_0.html
aperitivo in attesa del pranzo del 2014
:D
pegasoalatp
17-11-2008, 14:13
Period 30 Aug 2008 – 05 Sep 2008
1 Summary of Activities
The reporting period was characterised by the final navigation towards asteroid Steins which was flown-by on the night of the 5th of September 2008 at 18:38:20 UTC (time TBC). The navigation was completed with a trajectory control manoeuvre executed at ca. -36 hours from the closest approach.
The last navigation images confirmed that the spacecraft was well on track for the encounter. The flyby was conducted as expected with the spacecraft autonomously tracking the asteroid. No single error event was reported by the spacecraft. A more detailed analysis of the spacecraft performance will now be conducted with the data recorded on-board.
The bulk of the scientific operations was conducted in the hours around the encounter and will now continue for few days.
At the end of the reporting period (DoY 249) Rosetta was at 358.9 million km from Earth (2.39 AU); one-way signal travel time was 19 min 57 sec (1197 sec). The distance to Sun was 319.2 million km (2.13 AU). As from DoY 151/2008 Rosetta has entered a range of Sun distances that has never been
reached so far in the mission.
2 Satellite Status
2.1 Platform
2.1.1 AOCS / RCS
The AOCS configuration at the end of the reporting period is:
• AOCS in NM / attitude control based on wheels since DoY 2008.183.09.55. Detailed description of the asteroid fly-by event is reported in section 4.
• RCS: thrusters A nominal, B redundant. A trajectory correction manoeuvre of 0.118 m/s was executed on DoY 248 with the following timeline:
-- 248.06.21.00 FPAP > GSP
-- 248.07.21.56 GSP > FPAP
-- 248.07.25.46 FPAP > OCM (expected duration 104 sec, actual 103.5 sec)
-- 248.07.25.59 Start of Burn
-- 248.07.27.45 OCM > TTM (end of burn)
-- 248.07.29.24 TTM > WDP
-- 248.07.56.00 WDP > GSP
-- 248.08.56.00 GSP > FPAP
The fuel consumption during the OCM was 127.10 g
• Gyros: IMP A (red) OFF (since DoY129/2007), IMP B (meas) ON (since DoY 183/2008), IMPC (verif) ON (since DOY 217/2008).
• Reaction Wheels: all ON (since DOY 2008.183.09.20, wheel B since 2008.183.14:00), B declared as isolated in the SW. A wheel off-loading took place on DoY 248 05:00:00.
• ACM-A ON continuously, ACM-B ON continuously (since DOY 326/2006).
• Star Tracker A in use (since DOY 189/2008). STR A ON since DoY 189/2008; STR B OFF since DoY 189/2008. Both unit run SW 2.8. The STR never lost tracking during the fly-by, confirming the results of the test conducted in March 2008.
• NAVCAM A and B ON since DoY 217/2008 and used to take asteroid images and collection point tracking data. Since DoY 238 the spacecraft is permanently pointing to Steins and navigation images are taken daily. On DoY 248.17.11.50 CAM B generated EID 3252 CAM2-Cover Pos Reached Late i.e. similar behaviour as AR 145. No further action was taken. Both CAMs have been tested for asteroid tracking starting on DoY 249.06:00. Both cameras
immediately detected the asteroid, however in both cases the tracking data delivered were not satisfactory for the enabling of the autonomous tracking mode (SC AR to be written). The background noise was disturbing the measurements thus delivering a distorted set of data.
The control team spend several hours in finding a set of parameters that could allow the camera to deliver proper data. The final configuration was reached towards 248.14:20 when CAM B could properly track the asteroid. The final set of parameters included a window size of 350 pixels, 0.01 seconds integration time, and the filter in defocused-not attenuated
position. In this configuration the camera data were satisfying all the criteria set for the transition to autonomous tracking. When so configured also CAM A delivered satisfactory data and was then selected as prime for the fly-by. Preliminary analysis of the CAM data seem to show nominal performance throughout the fly-by.
• Gyro-stellar estimator ON since DoY 183/2008, gyro-less estimator OFF since DoY 183/2008.
• Auto-WOL Disabled (since DOY 137/2006).
• Deep Space flag set to TRUE (since DOY 298/2006)
• The SAS luminance threshold set to 0.000125 A since DoY 325/2007.
• The AOCS SW is in Cold configuration (patch 12 removed) since DoY 057/2008 The current guidance options are set as follows (since DOY 2008.183.20.00):
NM/NSHM: X Earth pointing, Y axis perp to Ecliptic, +Y South [EES]
Ref. axis [cos 30, 0, sin 30] i.e. 30 deg bias in +X/+Z quadrant
SHM: X Earth pointing, Y axis perp to Ecliptic, +Y South [EES]
Ref. axis [cos 30, 0, sin 30]
The recovery action for the linear range Sun surveillance had to be temporarily disabled during the flip manoeuvre and the fly-by since the Sun went out of plane during these manoeuvres. The AOCS SW triggered as expected at 249.18:02:45 and 249.18:36:08.
2.1.2 TT&C
The performance of the subsystem is nominal. The subsystem is configured for Active Cruise configuration since DOY 184/2008:
• TRSP-2 X-band up and down via HGA, 38 kbps downlink, 2kbps uplink.
• Back-up is configured for S-band reception at 7.8 bps via LGA-F as from DoY 021/2008
2.1.3 Thermal
The thermal behaviour of the spacecraft is nominal and stable.
The HW controlled heaters are in ACM2 configuration since DoY 183/2008.
The TCT is in ITM configuration since DoY 057/2008.
Occasional triggering of lines 15 and 30 of the PL TMT occur due to the spacecraft attitude. No action needs to be taken for these events.
2.1.4 Power
The subsystem is in its nominal configuration and performing nominally.
On DoY 243.14.56.31 the relay of the Thermal Knives B unexpectedly switched from OFF to ON (SC AR 163) thus raising a false alarm on the associated current level (TM parameter NPWD2878 TK B
CURRENT). The relay was successfully reset to OFF by commanding it. No explanation could be found till now.
On DoY 249.18.11.44, during the flip manoeuvre, the current of the SS PDU went out of limit (22.6 A).
This high value is due to a peak in the reaction wheels currents and could be expected. The database limit is kept very thigh on purpose.
2.1.5 Data handling
The subsystem is in its nominal hardware and software (v7) configuration.
SSMM runs SW version 1.6 since DOY 159/2005.
The TC link monitor time-out is set to 4 days since DoY 220/2008.
The TM generation mode is configured to “Weekly mode” since DoY 184/2008.
The System Init Table (SIT) is in “Normal” configuration since DoY 057/2008.
2.1.6 Mechanisms
All mechanisms are performing nominally.
The SADM is ON since DoY 183/2008 after NSHM exit. The SADM was operated with a limit on the max speed during the “flip” manoeuvre and the AFM to limit the disturbance on the spacecraft attitude.
The APM is ON since DoY 183/2008 after NSHM exit. The antenna pointing mechanism was kept OFF from 10 minute before closest approach to ca. 1 hour afterwards to limit the disturbance on the spacecraft attitude.
The effectiveness of such actions on the spacecraft pointing will be analysed in detail.
2.2 Payload
Most of the instruments have been activated as part of the fly-by campaign.
ALICE
The instrument was active during the fly-by and operations were conducted according to the plan.
CONSERT
The instrument is OFF.
COSIMA
The instrument was activated as part of the fly-by campaign. On DoY 245.10.13.22 COSIMA generated EID 41550 TMU error indicating a problem (SC AR 163). In coordination with the PI team the instrument operations were aborted and the instrument was switched OFF on DoY 246.
GIADA
The instrument was active during the fly-by and operations were conducted according to the plan.
MIDAS
The instrument is OFF.
MIRO
The instrument was active during the fly-by and operations were conducted according to the plan.
OSIRIS
The instrument was extensively used as part of the navigation campaign required for the approach to Steins. The last images for this activity were taken on DoY 248 between 11:00 and 13:00. These images allowed the mission control team at ESOC to assess the final targeting before the fly-by.
The instrument was later operated as part of the fly-by operations. Already in the approach phase the instrument generated a significant amount of shutter error events. Both cameras have been operating during the fly-by, with the NAC autonomously switching to safe mode at ca. 9 minutes before closest approach (SC AR to be written). The PI team could deliver shortly after the fly-by astonishing images taken with the WAC (see annex). The instrument remains active for the gravitational microlensing event observation.
ROSINA
The instrument was active during the fly-by and operations were conducted according to the plan. In few occasion the DFMS channel was autonomously switched OFF due to low temperature (SC AR to be written). In agreement with the PI team the instrument was reactivated shortly after the events.
RPC
The instrument was active during the fly-by and operations were conducted according to the plan.
RSI
The instrument is muted.
VIRTIS
The instrument was active during the fly-by and operations were conducted according to the plan. The PI team reported that the asteroid was not visible by the M channel for ca. 10 minutes after the end of the flip manoeuvre (SC AR to be written). Operations of the instrument are still affected by several
alarms for parameters values out of limits. The database and the FOP shall be reviewed accordingly.
LANDER Philae
The instrument was active during the fly-by and operations were conducted according to the plan. On DoY 248, when switching OFF the Lander Monitoring Circuitry, a current peak most probably triggered the current limiter for Lander Power inside ESS with subsequent switch OFF of the Lander (SC AR to be written). Upon request from the PI team, the ESS/LDR was power cycled by the nominal OBCPs with the usual switch ON procedure thus reactivating the Lander.
SREM
Since DoY 184/2008 the accumulation settings are configured for active cruise mode.
3 Ground Facilities
3.1 Ground Stations
During the reporting period mission operations have been conducted with support of the ESA and DSN ground stations.
Operations were conducted according to the plan with the exception of the DSN Goldstone antenna 14 which was not in a position to track the spacecraft immediately after the closest approach. The
NASA DSN team promptly reacted to this problem by offering DSS-15 within a short time. The antenna was then used to downlink the first scientific data of the fly-by.
To monitor the spacecraft status after the fly-by, the Cebreros tracking of DoY 249 was extended beyond the planned time with the antenna following the spacecraft below the 10 degrees elevation.
This action allowed the operations team to confirm successful fly-by as soon as TM was received at 249.20:14. No uplink was necessary during this extended tracking.
Changes to the DSN schedule had to be implemented due to a planning problem on RMOC side (GSAR 541). This had no impact on mission operations, except for the very late notification to DSN operators which kindly and promptly reacted to this issue.
3.2 Control Centre
The MCS SW version 3.11 is used on all operational chains since DoY 093/2008.
The FTS SW version 3.24 is used on the operational machines since DoY 093/2008.
4 Special Events
After a last correction manoeuvre on DoY 248 (see annexes for targeting reports), on the 5th of September 2008 at 18:38:20 UTC (TBC) Rosetta flew at 800 km from asteroid Steins marking an historical moment for the European space flight. For the first time a European spacecraft flew next to an asteroid, performed an optical navigation campaign, and autonomously tracked the asteroid by means of its on-board camera.[/B] All these experiences will prove to be of utmost importance for the
future steps of the Rosetta mission and for the further exploration of the solar system. The following table is a simplified version of the operations timeline that characterised the fly-by.
DoY SC Event
UTC
Ground Event
UTC Event / Activity
248 04/09/08 - 02:11:00 BoT NNO
248 04/09/08 - 05:00:00 04/09/08 - 05:19:50 Start TCM/WOL slot (AFB - 36h)
248 04/09/08 - 09:00:00 04/09/08 - 09:19:50 End TCM/WOL Slot (AFB - 36h)
248 04/09/08 - 11:00:00 04/09/08 - 11:19:50 Start last image acquisition for Navigation
248 04/09/08 - 14:00:00 BoT CEB
248 04/09/08 - 14:04:00 EoT NNO
248 04/09/08 - 16:00:00 04/09/08 - 16:19:50 Last image acquisition for Navigation
248 04/09/08 - 20:17:00 EoT CEB
249 05/09/08 - 00:00:00 BoT GDS
249 05/09/08 - 02:05:00 EoT GDS
249 05/09/08 - 02:08:00 BoT NNO
249 05/09/08 - 03:00:00 BoT CAN
249 05/09/08 - 06:00:00 05/09/08 - 06:20:00 Start NAVCAM Asteroid tracking attempts
249 05/09/08 - 09:00:00 Uplink of updated fly-by commands
249 05/09/08 - 11:00:00 EoT CAN
249 05/09/08 - 12:15:00 BoT CEB
249 05/09/08 - 14:05:00 EoT NNO
06/09/08 - 14:00:00 06/09/08 - 14:20:00 Final settings for NAVCAM defined
249 05/09/08 - 15:00:00 GO decision for AFM taken
249 05/09/08 - 16:00:00 NAVCAM A selected for AFM, final TCs uplinked
249 05/09/08 - 17:58:16 05/09/08 - 18:18:13 Start SC flip manoeuvre
249 05/09/08 - 18:18:16 05/09/08 - 18:38:13 End SC flip manoeuvre
249 05/09/08 - 18:18:46 05/09/08 - 18:38:43 Start asteroid closed loop tracking
249 05/09/08 - 18:28:16 05/09/08 - 18:48:13 Stop HGA tracking - Loss of TM signal
249 05/09/08 - 18:30:16 05/09/08 - 18:50:13 FDIR Disabled on-board
249 05/09/08 - 18:36:16 05/09/08 - 18:56:13 Phase angle zero crossing
249 05/09/08 - 18:38:22 05/09/08 - 18:58:13 Closest-approach
249 05/09/08 - 19:38:16 05/09/08 - 19:58:13 End of asteroid closed loop tracking
249 05/09/08 - 19:48:16 05/09/08 - 20:08:13 FDIR Re-enabled on-board
249 05/09/08 - 19:54:00 05/09/08 - 20:14:00 Resume HGA tracking - Acquisition of TM signal
249 05/09/08 - 20:43:00 EoT CEB
249 05/09/08 - 22:35:00 BoT GDS
249 05/09/08 - 23:20:00 Start science data downlink
250 06/08/09 - 02:06:00 BoT NNO
250 06/08/09 - 02:45:00 EoT GDS
250 06/08/09 - 14:01:00 EoT NNO
251 07/09/08 - 14:00:00 07/09/08 - 14:20:11 End of pointing
The spacecraft behaved very well during the fly-by and no single parameter indicated a problem.
Detailed analysis of the dynamic behaviour of the spacecraft will now be performed once all the data
are available.
6 Future Milestones
The fly-by operations will continue now with further observations for few days. The data downlink phase will last till beginning of October, interleaved with OSIRIS science observations. The spacecraft will then continue its 4th orbit round the Sun reaching aphelion on the 17th of December 2008 at a distance of 2.26 AU to head back to the Earth for the third and last swing-by on the 13th of November 2009.
Un po' di immagini a risoluzione piena del flyby di Marte del 2007...
- Immagine "scattata (http://www.esa.int/esaCP/SEMFTZM0LYE_index_0.html)" dal lander Philae (in particolare da ÇIVA):
http://www.esa.int/images/CIVA_Mars_30_H.jpg
- Marte in diverse (http://www.esa.int/esaCP/SEMUDT70LYE_index_0.html) "bande":
rosso, verde e vicino-ultravioletto:
http://www.esa.int/images/MarsNACColorCloudEnhanced_UV_H.JPG
vicino-infrarosso, verde e vicino-ultravioletto:
http://www.esa.int/images/colour_composite_nir_green_nuv_H.JPG
e a colori veri:
http://www.esa.int/images/MarsNACTrueColor_square_2_H.JPG
- Sala di controllo (http://www.planetary.org/blog/article/00000883/)della missione:
http://farm1.static.flickr.com/142/402039015_b416491d85_b.jpg
Ultimo flyby della Terra per Rosetta:
Rosetta Prepares For Last Earth Flyby (http://www.onorbit.com/node/1630)
ESA's Rosetta comet chaser will swing by Earth on 13 November to pick up orbital energy and begin the final leg of its 10-year journey to the outer Solar System. Several observations of the Earth-Moon system are planned before the spacecraft heads out to study comet 67/P Churyumov-Gerasimenko.
This will be the third Earth swingby, the last of Rosetta's four planetary gravity assists. Closest approach to Earth is expected at 08:45 CET. The swingby will provide exactly the boost Rosetta needs to continue into the outer Solar System. The craft is scheduled for a close encounter with asteroid 21 Lutetia in July next year.
Rosetta is expected to arrive at its final destination in May 2014. There, it will release the Philae lander for in-situ studies on the surface. The spacecraft will then escort the comet on its journey toward the Sun, studying it closely for up to two years.
As it closes in on Earth next month, Rosetta will have travelled almost 4500 million km since launch. It will speed past Earth at 13.3 km/s, passing above the Indian Ocean at 109 degrees E, 8 degrees S, just south of the Indonesian island of Java. The gravity-assist will increase the spacecraft's speed by 3.6 km/s with respect to the Sun.
Instruments in Action
While the swingby is critical for achieving the velocity required to reach its ultimate destination, the close encounter will also be used to study the Earth-Moon system from Rosetta's unique perspective.
Several instruments that usually hibernate during the long trek will be turned on in the week before the swingby.
Follow the Swingby Live
The Rosetta Blog will be updated regularly for this final planetary swingby. Follow crucial events live via the blog and the dedicated ESA Rosetta mission website.
Critical Swingby Events
Closest approach is scheduled for 08:45 CET on 13 November, but mission operators will perform a number of critical actions before and after the swingby to ensure that Rosetta is on the right trajectory.
One of the most important will be a trajectory correction maneuver (TCM), scheduled for 22 October at 14:30 CET. Results of this maneuver will be analyzed to determine whether additional TCMs are required to achieve the correct approach trajectory.
Notes:
All times are in Central European Time (CET/CEST)
TCM: Trajectory correction maneuver
DSN: Deep Space Network (NASA)
DSA: Deep Space Antenna (ESA)
22 October
14:30 - 21:30 Slot for TCM
5 November
12:30 - 19:30 Slot for TCM if needed
6 November
Beginning 22:45 Instruments switched on to begin
observations of the Earth-Moon system
12 November
10:30 - 17:30 Slot for TCM if needed
13 November
01:00 - 08:00 Slot for TCM if needed
08:45 Earth closest approach
09:04 - 10:55 Swing by confirmation via Maspalomas
ground station, Canary Islands
11:00 - 21:00 Start science data download via NASA
DSN Goldstone, California
16:41 Moon closest approach
21:13 - 5:04 (14 November) ESTRACK DSA New Norcia
ground station pass, Australia
19 November
By 12:05 Instruments turned off
http://www.planetary.org/image/NAC_ESB3_Moon_First_Look_lg.png (http://www.planetary.org/image/NAC_ESB3_Moon_First_Look.png)
Rosetta is homing in on Earth (http://www.planetary.org/blog/article/00002199/)
Heads up! ESA's Rosetta spacecraft is approaching for its last flyby of Earth, on Friday, November 13. It is now close enough that its OSIRIS high-resolution camera can resolve the Moon (and presumably Earth as well). Here's that photo of the Moon, a lovely crescent view captured on Sunday from 4.3 million kilometers away:
http://www.planetary.org/image/osiris_color_2009-11-12T12.28UTC_rot_north_lg.png (http://www.planetary.org/image/osiris_color_2009-11-12T12.28UTC_rot_north.png)
Crescent Earth (http://www.planetary.org/blog/article/00002203/)
Just hours away from its Earth flyby, Rosetta is busily snapping images and gathering other science data. Among other things, it's using its spectrometric instruments to try to follow up on the Moon water discovery made by Chandrayaan-1, Cassini, and Deep Impact earlier this year; it's gathering tracking data to follow up on the investigation of the "flyby anomaly"; and it's gathering some images for purely photographic purposes, including this lovely view of our Earth as a skinny crescent.
pegasoalatp
26-12-2009, 16:49
During the reporting period the mission performance has been nominal. The scientific observations linked to the Earth swing-by phase were concluded successfully. On the 23rd of November a correction manoeuvre (ca. 58 cm/s) was executed to clean-up the small inaccuracy of the swing-by.
The bulk of the activities required for the refresh of all spacecraft EEPROMs was conducted during last week. The behaviour of RW B is still not nominal and keeps being closely monitored.
DOY Date Pass Main Activity
318 14/11/09 NNO 2089 Monitor
319 15/11/09 DSS-24 2090
NO 2090 Monitor
320 16/11/09 NNO 2091 Monitor
321 17/11/09 DSS-54 2092
DSS-24 2092
NNO 2092 Monitor
322 18/11/09 DSS-24 2093
NNO 2093 Monitor
323 19/11/09 NNO 2094 Monitor
324 20/11/09 NNO 2095 Monitor
326 22/11/09 DSS-54 2097 Refresh PM2 / PM3 EEPROM images
327 23/11/09 NNO 2098 Clean-up TCM
328 24/11/09 NNO 2099 Refresh STR B / CAM B EEPROM images
329 25/11/09 NNO 2100 Refresh PM1 / PM4 EEPROM images
330 26/11/09 NNO 2101 Refresh STR A / CAM A EEPROM images
331 27/11/09 NNO 2102 Monitor
At the end of the reporting period (DoY 331) Rosetta was at 11 million km from the Earth (0.073 AU); one-way signal travel time was 0 min 37 sec (37 sec). The distance to Sun was 146.87 million km (0.982 AU). On DoY 327 Rosetta was at the perihelion of its current orbit (146.6 million km or 0.98 AU); after having executed the 2 deep space manoeuvres in 2011 and 2014 Rosetta will never come back again so close to the Sun.
pegasoalatp
26-12-2009, 16:59
- Sala di controllo (http://www.planetary.org/blog/article/00000883/)della missione:
http://farm1.static.flickr.com/142/402039015_b416491d85_b.jpg
Correggo leggermente, questa e' la Main Control Room. Viene utilizzata da tutte le missioni per i primi giorni dopo il lancio (tipicamente la LEOP) o per casi particolari (caso dell' articolo)
Dopo, le missioni sono controllate in altre sale dedicate (meno "stilose").
Correggo leggermente, questa e' la Main Control Room. Viene utilizzata da tutte le missioni per i primi giorni dopo il lancio (tipicamente la LEOP) o per casi particolari (caso dell' articolo)
Dopo, le missioni sono controllate in altre sale dedicate (meno "stilose").
Grazie della correzione :)
Una curiosità: su cosa si basa la scelta di utilizzare la Main Control Room? Ovvero i "casi particolari" sono semplicemente quelli importanti per la missione (ad esempio grosse "manovre"/flyby di pianeti) o c'è qualche criterio più complesso?
pegasoalatp
27-12-2009, 17:23
Credo che la prima discriminante sia la disponibilita' della sala (nessun lancio in quell' intorno di tempo), poi motivi di Public Relations: portare i giornalisti nella MCR e' molto piu' "scenografico".:D
Results from the Rosetta Encounter with Asteroid 2867 Steins (http://www.planetary.org/blog/article/00002301/)
Last week in Science magazine appeared the first peer-reviewed article on the results of Rosetta's September 2008 encounter with the smallish main-belt asteroid Steins. This morning I got a chance to sit down and read the article, and I wrote up a summary; basically, the article is a description of what asteroid Steins looks like and what it's likely made of. The single item in the article that'll be cited the most is the basic fact of Steins' dimensions, which are: 6.67 by 5.81 by 4.47 kilometers, equivalent in volume to a sphere with a radius of 2.65 kilometers.
Other notable items:
* The Rosetta images have the south pole up -- it's the south pole that's dominated by an impact crater 2.1 kilometers in diameter.
* There's been much debate on the nature of a line of craters visible along the terminator in the Rosetta images. H. Uwe Keller and his coauthors have decided that this line of craters is real, and they probably are not impact craters, but are instead collapse pits over some subsurface fracture.
* It's almost certainly a rubble pile.
* Steins seems to have a curious rotational history. Its shape strongly suggests that, like many small asteroids, it was "spun up" by solar radiation effects, and the high spin rate caused its rubble to redistribute to a double-cone shape with a strong equatorial bulge. However, it is not presently spinning fast enough for these shape changes to happen.
4chr
pegasoalatp
26-07-2010, 11:26
Summary of Activities
On DoY 191 (10 July 2010 at ca. 15:44:57 UTC) Rosetta successfully flew next to asteroid (21) Lutetia with a relative speed of 15 km/s. The spectacular flyby manoeuvre was conducted as planned with the spacecraft autonomously tracking the asteroid; a large subset of the payload complement was activated for scientific operations. Preliminary analysis indicates that spacecraft performance have been nominal throughout the flyby, detailed analysis will be conducted in the coming weeks in support of the science data processing. The scientific payload worked as planned with few anomalies in a couple of instruments. Preliminary images delivered by the science camera indicate a very successful
data acquisition with very promising scientific results. Operations are now focused to the data
downlink that will last few weeks.
DoY Date Pass Activity
186 05/07/10 NNO 2322 Navigation Slot 15 - Start of science campaign
187 06/07/10 NNO 2323 Navigation Slot 16
188 07/07/10 DSS-24 2324 NNO 2324 Navigation Slot 17
189 08/07/10 NNO 2325 DSS-65 2326 Navigation Slot 18
190 09/07/10 DSS-24 2326 NNO 2326 CEB 2327 DSS-26 2327 Navigation Slot 19
191 10/07/10NNO 2327 DSS-34 2327 DSS-63 2328 CEB 2328 DSS-24 2328
Verification of CAM tracking
Back-up to NNO
Closest approach operations
Back-up to DSS-63
AFB Data downlink
At the end of the reporting period (DoY 191) Rosetta was at 454 million km from the Earth (3.03 AU); one-way signal travel time was 25 min 21 sec (1521 sec). The distance to Sun was 406.12 million km (2.71 AU). The distance to the asteroid at closest approach was 3160 km.
Special Events
The second and last asteroid flyby was conducted as planned on 10 July 2010. The spacecraft went through the delicate mission phase without any problem and all of the planned operations were executed.
The navigation campaign was successfully conducted with the images acquired by the spacecraft navigation camera and the OSIRIS science camera. A total of 272 images were used to determine the spacecraft and the asteroid relative trajectories. Only the 1st of the 5 slots for correction manoeuvres was used 3 weeks before the encounter. The last orbit determination before the encounter showed a nominal miss distance (3160 km) with a negligible error (ca. 0.1deg) on the flyby plane.
The spacecraft navigation cameras were also used to track the asteroid in closed loop during the closest approach phase. After a careful check of their performance it was decided to use CAM A and to delay the entry in closed loop tracking at the latest planned time (CA-1h); this was done in order to minimise the effect of the small disturbances of charged particles hitting the CAM CCD. After the closest approach the camera stopped detecting pixels above the selected threshold at 191.15:52:41.
Preliminary analysis of data seems to show nominal performance throughout the phase.
The timeline of the event was as follows:
DoY Epoch (UTC) Event
191 10/07/10 - 03:33:00 BoT NNO
191 10/07/10 - 06:00:00 Final NAVCAM Asteroid tracking check
191 10/07/10 - 08:30:00 GO for Asteroid Flyby Mode and uplink of TCs
191 10/07/10 - 11:05:00 BoT DSS-63
191 10/07/10 - 11:24:55 Start SC flip manoeuvre
191 10/07/10 - 12:04:55 End SC flip manoeuvre
191 10/07/10 - 14:44:55 Started asteroid closed loop tracking
191 10/07/10 - 15:39:55 Stopped HGA tracking - Loss of TM signal (earliest)
191 10/07/10 - 15:44:57 Closest-approach (3160 km)
191 10/07/10 - 15:45:55 Inhibition of CAM measurement for asteroid tracking (Sun blinding)
191 10/07/10 - 16:04:55 End of asteroid tracking mode
191 10/07/10 - 16:19:55 Resumed HGA tracking - Acquisition of TM signal
191 10/07/10 - 17:40:37 Science data downlink
191 10/07/10 - 21:55:00 EoT DSS-63
Future Milestones
The peak phase of the flyby operations is now over and the mission will continue with the science data downlink phase for the next few weeks. After this quiet phase mission operations will focus on the preparation of the deep space phase.
--------------
http://www.esa.int/images/2_Lutetia_and_Saturn,0.jpg
Asteroide Lutetia in primo piano e sullo sfondo Saturno (foto:ESA)
---------------------------------------
http://www.esa.int/images/4_closest_approach,0.jpg
Lutetia da vicino (foto:ESA)
pegasoalatp
02-08-2010, 14:18
At 31 July, Rosetta was at 509 million km from the Earth (3.4 AU); one-way signal travel time was 28 min 18 sec (1698 sec). Since the 22nd of July Rosetta has passed its own record of Earth distance.
The distance to Sun was 427.7 million km (2.85 AU).
The distance to the asteroid at closest approach was 3160 km.
Since the 12th of July Rosetta is the solar-powered spacecraft that has flown furthest from the Sun ever. This record distance will be almost doubled at aphelion in 2012 (5.29 AU).
fonte (come sempre): ESA
pegasoalatp
11-02-2011, 10:47
Si prosegue altrove ... (http://www.hwupgrade.org/forum/viewtopic.php?f=100&t=24973&p=586087#p586087) <----- altrimenti, provate a Googlare un pochino ! :D
jumpjack
11-02-2011, 13:04
Eh?!? :confused:
pegasoalatp
13-02-2011, 22:29
Eh?!? :confused:
allora, entra nel lato oscuro (della forza). :D
jumpjack
20-01-2014, 18:43
[2 marzo 2004]
0717 GMT (2:17 a.m. EST)
LIFTOFF! The Rosetta spacecraft begins its journey to comet Churyumov-Gerasimenko aboard the Arianespace Ariane 5 rocket!
E' un anno di "eventi spaziali" importanti, questo! :D
Oltra al compleanno di Spirit e Opportunity, eccoci, sempre dopo 10 anni, a un altro evento spaziale importante: la missione "Stele di Rosetta" entra nel vivo.
Una missione affascinante, con una sonda che, lanciata nel 2004, è "rimbalzata" da un pianeta all'altro del sistema solare per acquisire tutta la spinta necessaria per mettersi alle costole di una cometa dal nome impossibile, 67P/CHURYUMOV-GERASIMENKO. Osservate il video:
http://sci.esa.int/rosetta/52838-twelve-year-journey-in-space/
Oggi, dopo 957 giorni di ibernazione, o di standby che dir si voglia, i timer di bordo sono "scattati" e, senza alcun intervento da Terra, hanno risvegliato la sonda dormiente, pronta ad iniziare a scattare foto strabilianti di una cometa attualmente "spenta" ma che presto verrà "accesa" dal Sole, per poi addirittura lanciare un lander, Philae, che, per la prima volta nella storia, atterrerà sulla cometa!
Speriamo che la politica ESA di rilascio delle immagini sia all'altezza della missione!!
Il lander:
http://sci.esa.int/science-e-media/img/37/Philae_on_the_comet_back_view_625.jpg
Grande jump, so di poter contare su di te! (soprattutto dopo che ho perso i link ai 3d e mi tocca sempre andare di egosearch... :D)
Riporto anche l'articolo completo dell'ESA:
http://www.esa.int/Our_Activities/Space_Science/Rosetta/ESA_s_sleeping_beauty_wakes_up_from_deep_space_hibernation
E quello dell'ASI:
http://www.asi.it/it/news/il_grande_giorno_di_rosetta
Il grande giorno di Rosetta
Dopo 31 mesi di ibernazione, il segnale a lungo atteso è stato ricevuto alle 19.20 dal centro ESOC di Darmstadt che ha poi annunciato ufficialmente il risveglio della sonda attraverso l’account Twitter dedicato alla missione
http://www.asi.it/files/imagecache/news_image/images/ROSETTA_1.jpg
20 Gen 2014
L’attesa è finita. Alle 19 e 20 di questa sera (ora italiana, le 18:20 GMT) la sonda Rosetta ha finalmente inviato il suo segnale verso Terra, regalando agli scienziati e ai tanti appassionati della missione, la prova definitiva del suo risveglio. "La tensione è stata davvero tanta - ha commentato a caldo Enrico Flamini, Chief Scientist ASI - ma adesso la soddisfazione è al massimo. Nei prossimi giorni avremo modo di capire se è tutto a posto".
A partire dalle 21 e 34 l'antenna dellla stazione di New Norcia, situata nella parte occidentale dell'Australia inizierà a seguire la sonda.
La prima fase del risveglio è cominciata alle 10 di questa mattina, quando l'orologio interno l'ha ridestata da 31 mesi di sonno. Subito dopo Rosetta ha compiuto una rotazione su se stessa per poter dirigere verso il nostro pianeta la sua antenna, in modo da comunicare con il centro di controllo ESOC dell’ESA, a Darmstadt. A quel punto, ha iniziato a mandare informazioni a Terra sullo stato dei suoi sistemi principali e, via via, dei suoi strumenti.
“Rosetta è una grande sfida, la più difficile mai intrapresa nella storia del volo spaziale – ha affermato Thomas Reiter direttore del Volo Umano all’ESA durante l’evento a Darmstadt che ha coperto da questa mattina tutte le fasi del risveglio – vogliamo ringraziare tutti i nostri partner per il supporto che ci hanno dato in questi dieci anni di missione”.
Ma la giornata di oggi, se segna l'atteso ritorno delle comunicazioni di Rosetta e solleva molti dal timore che restasse a dormire, rappresenta solo un altro passo della missione: la prossima sfida è prevista per il mese di aprile quando è previsto il check up degli strumenti e dei sottosistemi a bordo.
La sonda dell’ESA, lanciata nel 2004 e realizzata grazie ad un rilevantissimo contributo dell'Agenzia Spaziale Italiana, è attualmente in viaggio nello spazio profondo, in attesa di raggiungere la sua meta finale: la cometa 67P/Churyumov-Gerasimenko. Rosetta è composta da un orbiter, dove sono situati i sensori per gli esperimenti di remote sensing e da unlander, chiamato Philae, che verrà rilasciato sulla superficie della cometa per effettuare una serie di misure delle caratteristiche fisiche della superficie e per studiare la struttura interna del nucleo.
Il principale obiettivo scientifico della missione è la comprensione dell’origine delle comete e delle relazioni tra la loro composizione e la materia interstellare, per potere risalire alle origini del Sistema solare, che la sonda ha già viaggiato in lungo e in largo.Un obbiettivo ambizioso, cui corrispondono nomi adeguati: Rosetta e Philae sono infatti rispettivamente un omaggio alla stele e all'obelisco (ritrovato sulla omoniva isola del Nilo) che hanno dato un contributo fondamentale alla decifrazione dei geroglifici egiziani.Rosetta ha orbitato intorno al Sole cinque volte e, nell’arco di sette anni, ha già sorvolato tre volte la Terra, Marte nel febbraio 2007 e ben due asteroidi: 2867 Šteins, il 5 settembre 2008, e 21 Lutetia, il 10 luglio 2010.
A luglio 2011 è iniziata la sua avventura in “solitaria”: è stata messa a riposo mentre si muoveva verso l’orbita di Giove, dopo aver completato l’allineamento con la cometa. Rosetta dovrà percorrere ancora 9 milioni di chilometri per raggiungere il suo obbiettivo e solo ai primi di maggio si troverà a circa 2 milioni di chilometri di distanza. Successivamente cominceranno le manovre per l’allineamento all’orbita della cometa e si preparerà alla sua mappatura (l’esatta forma della cometa è ad oggi sconosciuta).Il rendez-vous avverrà ad agosto.
Una volta incontrata la cometa, i ricercatori a terra riceveranno migliaia di immagini, che permetteranno di aggiustare la traiettoria per il lancio del lander. L’atterraggio di questo, previsto per novembre, costituirà un evento di importanza fondamentale poiché per la prima volta alcuni strumenti costruiti dall’uomo atterreranno su una cometa. Philae si ancorerà alla superficie grazie a due arpioni che ne impediranno il rimbalzo in orbita.
Da quel momento in poi cominceranno i veri e propri esperimenti: una trivella scaverà fino a 20 centimetri dalla superficie per raccogliere una serie dicampioni che verranno poi analizzati a bordo.La partecipazione italiana alla missione consiste di tre strumenti scientifici dell’orbiter: VIRTIS (Visual InfraRed and Thermal Imaging Spectrometer) il cui PI è Fabrizio Capaccioni dell’IAPS (INAF Roma), GIADA (Grain Impact Analyser and Dust Accumulator) il cui PI è Alessandra Rotundi (dell’Università Parthenope di Napoli), e la WAC (Wide Angle Camera) di OSIRIS del prof. Cesare Barbieri dell’università di Padova.
A bordo del lander, è italiano il sistema di acquisizione e distribuzione dei campioni (SD2), il cui PI è la prof.ssa Amalia Ercoli Finzi del Politecnico di Milano, ed il sottosistema dei pannelli solari.La fine della missione, è prevista per l’ultima parte del 2015: una volta completate le indagini sulle caratteristiche della cometa,Rosetta (con il lander Philae, che si poserà sul nucleo a novembre) scorterà 67P/Churyumov-Gerasimenko verso il Sole.
Raggiungeranno il perielio ad agosto, poi proseguiranno sempre insieme nella traiettoria di allontanamento. La sonda dovrebbe quindi smettere di mandare dati a Terra a dicembre 2015.
Sulla pagina LiveStream di ESA TV stanno rimandando in ciclo il video dal centro di controllo dell'ESOC a Darmstadt nel il momento in cui arriva il segnale di ritorno da Rosetta.
www.livestream.com/eurospaceagency
Oggi, dopo 957 anni di ibernazione, o di standby che dir si voglia, ...
:eek: miseria! E che è, il nonno di VIGER ? :D
jumpjack
27-01-2014, 09:16
:eek: miseria! E che è, il nonno di VIGER ? :D
non so di cosa parli ;-)
Scherzo, ho corretto, grazie.
Inviato dal mio HUAWEI G510-0100 utilizzando Tapatalk
jumpjack
01-08-2014, 11:14
-5
http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/07/comet_on_29_july_2014/14682189-1-eng-GB/Comet_on_29_July_2014_node_full_image_2.png
Mancano 5 giorni all'ingresso in orbita. :sbav:
Arrival at Churyumov-Gerasimenko is scheduled for Aug. 6, when Rosetta will become the first spacecraft to ever enter orbit around a comet.
Mission Status Center (anche se pare bloccato su gennaio...):
http://www.spaceflightnow.com/rosetta/status.html
NasaSpaceFlight forum:
http://forum.nasaspaceflight.com/index.php?PHPSESSID=9af7afh6lag8lrqs495jse6fd1&topic=6642.225
UnmannedSpaceFlight forum:
www.unmannedspaceflight.com/index.php?showtopic=7835&st=0
Blog ufficiale:
http://blogs.esa.int/rosetta/2014/07/24/hints-of-features/
jumpjack
01-08-2014, 11:23
25 luglio:
http://blogs.esa.int/rosetta/files/2014/07/ESA_ROSETTA_NAVCAM_20140725_full.jpg
28 luglio:
http://blogs.esa.int/rosetta/files/2014/07/ESA_ROSETTA_NAVCAM_20140728_full_g05.jpg
29 luglio:
http://blogs.esa.int/rosetta/files/2014/07/ESA_ROSETTA_NAVCAM_20140729_full_g05.jpg
30 luglio:
http://blogs.esa.int/rosetta/files/2014/07/ESA_ROSETTA_NAVCAM_20140730_full_g05.jpg
I rispettivi zoom:
25 luglio:
http://blogs.esa.int/rosetta/files/2014/07/ESA_ROSETTA_NAVCAM_20140725_cropped_interpolatedx10.jpg
28 luglio:
http://blogs.esa.int/rosetta/files/2014/07/ESA_ROSETTA_NAVCAM_20140728_cropped_interpolatedx10_g05.jpg
29 luglio:
http://blogs.esa.int/rosetta/files/2014/07/ESA_ROSETTA_NAVCAM_20140729_cropped_interpolatedx10_g05.jpg
http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/07/comet_on_29_july_2014/14682189-1-eng-GB/Comet_on_29_July_2014_node_full_image_2.png
30 luglio:
http://blogs.esa.int/rosetta/files/2014/07/ESA_ROSETTA_NAVCAM_20140730_cropped_interpolatedx10_g05.jpg
jumpjack
05-08-2014, 23:07
Domattina non vi scordate il tablet, per la diretta sotto l'ombrellone alle 10.00! (08:00 GMT)
http://rosetta.esa.int/
jumpjack
05-08-2014, 23:28
2014/08/06 00:25
#Rosetta is flying her last kilometers to Comet #67P tonight, after flying over 4 billion kilometers in 10 years. Orbit insertion tomorrow!
https://twitter.com/timmermansr/status/496783759120015362
jumpjack
05-08-2014, 23:29
Dati presumibilmente in tempo reale:
http://www.livecometdata.com/comets/67p-churyumov-gerasimenko/
jumpjack
05-08-2014, 23:32
When #Rosetta's radio signals arrive on Earth, they have a power of just 0.0000000000000000000000270 W!
https://twitter.com/esaoperations/status/496645408702353408
jumpjack
05-08-2014, 23:38
http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/07/rotating_view_of_comet_on_14_july_2014/14628956-1-eng-GB/Rotating_view_of_comet_on_14_July_2014_node_full_image_2.gif
http://www.esa.int/spaceinimages/Images/2014/07/Rotating_view_of_comet_on_14_July_2014
https://www.nasa.gov/sites/default/files/pia18419_main_updated_0.gif
https://www.nasa.gov/jpl/rosetta/comet-67p-churyumov-gerasimenko-20140724/#.U-FdrtJ_v88
jumpjack
05-08-2014, 23:49
Orbita triangolare:
http://www.esa.int/spaceinvideos/Videos/2014/08/How_to_orbit_a_comet
jumpjack
06-08-2014, 08:38
Diretta web su Euronews:
http://www.euronews.com/2014/07/31/live-rosetta-the-comet-hunter-arrives-at-its-target-67p-churyumov-gerasimenko/
Diretta Web ESA:
http://rosetta.esa.int/
L'hanno già bella che stampata in 3d:
https://twitter.com/rebeccamorelle/status/496904542081282048
https://pbs.twimg.com/media/BuVcC_XIQAAgWZx.jpg
jumpjack
06-08-2014, 08:50
Per chi ci capisce qualcosa, ecco come seguire l'evento via satellite:
http://www.esa.int/esatv/Transmissions/2014/08/Rosetta_arrives_at_Comet
Magari si potesse anche semplicemente con Sky... :mbe:
jumpjack
06-08-2014, 11:14
Arrivati in orbita!
http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/08/navcam_animation_6_august/14705553-1-eng-GB/NavCam_animation_6_August.gif
http://www.esa.int/spaceinimages/Images/2014/08/NavCam_animation_6_August
https://pbs.twimg.com/media/BuWMwIiIAAA7k4L.png:large
jumpjack
06-08-2014, 14:03
Exact time of comet arrival for @ESA_Rosetta today: 09:02:29 UTC on board #67P
https://twitter.com/esaoperations/status/496974899706347521
jumpjack
06-08-2014, 14:05
Anche se non sembra, la cometa è già leggermente in "eruzione":
http://planetary.s3.amazonaws.com/assets/images/9-small-bodies/2014/20140806_Comet_activity_on_2_August_2014_f537.png
http://www.planetary.org/blogs/emily-lakdawalla/2014/08060249-were-at-the-comet-rosetta.html
+Benito+
06-08-2014, 14:06
che roba strana..la parte a destra sembra un divergente di un motore, sono curioso di vedere se è una via preferenziale di emissione una volta che sentirà il calore del sole.
Edit: guardando la gif si vede che è solo il bordo di un cratere-
Si sa già quando la fanno partorire?
+Benito+
06-08-2014, 14:11
http://planetary.s3.amazonaws.com/assets/images/9-small-bodies/2014/20140806_Comet_close-up.png
2,2 m/px!
jumpjack
06-08-2014, 14:26
Si sa già quando la fanno partorire?
Si atterra a novembre, dopo già diverse settimane che la cometa sarà in piena eruzione!
Un'altra immagine a 2,4 m per pixel
http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/08/comet_details/14710766-1-eng-GB/Comet_details_fullwidth.png
http://www.esa.int/Our_Activities/Space_Science/Rosetta/Highlights/Postcards_from_Rosetta
jumpjack
06-08-2014, 14:28
L'incredibile viaggio di Rosetta:
https://www.youtube.com/watch?v=qa0EjIYnHTE
+Benito+
06-08-2014, 15:16
che cosa straordinaria! Riuscire a mandare un cubo di ferraglia in orbita attorno ad un sassolino nel nulla cosmico mentre questo si muove a milioni e milioni di km da qui.
Quoto Benito, e ringrazio jump per gli updates!
Congratulazioni all'ESA e tutti i contractors e gli enti di ricerca coinvolti per questo incredibile risultato.
:) :ave:
Non ricordo se fosse già stato postato...
http://sci.esa.int/where_is_rosetta/
stefano1234
08-08-2014, 09:37
Si atterra a novembre, dopo già diverse settimane che la cometa sarà in piena eruzione!
Un'altra immagine a 2,4 m per pixel
http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/08/comet_details/14710766-1-eng-GB/Comet_details_fullwidth.png
http://www.esa.int/Our_Activities/Space_Science/Rosetta/Highlights/Postcards_from_Rosetta
non si capisce pero' quanto e' grande la cometa 10 km? e quei 2 massi a sinistra della doppia w quanto saranno larghi? 30 mt? 100mt?
Vista cosi' sembra squamata come i ghiacciai di montagna in via di scioglimento-fusione.Sara' mica una palla di ghiaccio sporco? tutta acqua....
jumpjack
08-08-2014, 20:45
non si capisce pero' quanto e' grande la cometa 10 km? e quei 2 massi a sinistra della doppia w quanto saranno larghi? 30 mt? 100mt?
Vista cosi' sembra squamata come i ghiacciai di montagna in via di scioglimento-fusione.Sara' mica una palla di ghiaccio sporco? tutta acqua....
Sì, una scala sarebbe utile... cmq se 1 pixel = 2 m e un masso e' largo 20 pixel, sono 40 m.
+Benito+
08-08-2014, 22:39
è una cometa, in base alle conoscenze attuali sono quasi tutte "palle di neve sporche", vuol dire polvere e ghiaccio. Questa missione ne darà conferma o introdurrà nuove ipotesi.
jumpjack
10-11-2014, 22:26
Tutto pronto per l'atterraggio di mercoledì 12 novembre... anche il mio modellino stampato in 3d :)
http://jumpjack.wordpress.com/2014/10/29/modello-3d-stampato-della-cometa-67pchuryumov-gerasimenko-missione-rosetta/
Tabella di marcia (ora italiana):
12 nov
02:35: Conferma finale che la sonda è su traiettoria esatta
05:03 Inizio operazioni di SDL (Separazione, Discesa, Atterraggio)
05:28 Avvio software per SDL
05:34 Pre-riscaldamento batterie lander
07:03-08:03 Ultima manovra di pre-posizionamento
07:35-08:35 Conferma di attuabilità dello sgancio del lander Philae
09:46 Accensione meccanismo di sgancio (MSS): accensione motori di sgancio
09:53 Il lander commuta sulle batterie, diventando indipendente dall'orbiter; inizio rotazione viti di sgancio
xx:xx Sgancio Philae, alla velocità di 0,6 km/h
xx:xx Orientamento della telecamera dell'orbiter verso il lander; l'orbiter prosegue sulla sua orbita
10:03 Arrivo a terra delle telemetrie di avvenuto sgancio di Philae
xx:xx Connessione dati tra lander e orbiter
11:53 Arrivo a terra della conferma di comunicazione stabilita tra Philae e Rosetta e della possibilità di Philae di comunicare con la Terra tramite Rosetta. Le sonde resteranno in contatto radio diretto fino a 90 minuti dopo l'atterraggio
Discesa sulla cometa, della durata di 7 ore
12:59 Arrivo primi dati e immagini a terra da lander e orbiter
16:01 Il lander fotografa la sequenza di atterraggio con le telecamere di bordo
xx:xx Arrivo sulla superficie della cometa alla velocità di 3-4 km/h (passo d'uomo); per evitare rilmbalzi, la sonda lancerà due arpioni, e mentre un piccolo motore a gas compresso la manterrà aderente alla cometa, al contatto delle zampe col suolo da esse fuoriusciranno tre trivelle che si avviteranno letteralmente sul terreno per trattenere in modo stabile il lander per la durata della missione, che terminerà nominalmente a dicembre 2015, dopo che la cometa avrà raggiunto e superato il perielio, il punto di minima distanza dal sole.
17:02 Arrivo a terra della conferma dell'atterraggio, circa 30 minuti dopo (circa 600 mln di km di distanza)
17:40 Sequenza di atterraggio completata. Il lander invia all'orbiter telemetrie e foto.
64 ore di missione primaria "a batteria", a prescindere dallo stato di illuminazione dei pannelli solari
Foto panoramica a 360° della superficie, di cui una parte in 3d
trivellazione del sottosuolo fino a 23 cm di profondità
Nota: gli scienziati che hanno commissionato la missione ad ESA hanno 6 mesi di diritti esclusivi su tutte le immagini scattate nel corso della missione: tutte le immagini rilasciate prima del 12 maggio 2015 sono quindi da considerarsi un regalo e uno strappo alla regola...:rolleyes:
Sull'orbiter c'è una fotocamera con ben 16 filtri colorati, OSIRIS; finora nessuna immagine a colori è stata rilasciata, ci sono solo immagini colorizzate a mano.
http://download.esa.int/esoc/shares/1/Rosetta_PressKit_CometLanding_November2014_v4.pdf
http://download.esa.int/esoc/shares/1/esa_esoc_ros-ldr-landing_timeline_web08112014.pdf
Le immagini della stampa saranno disponibili tramite FTP (???):
ftp://tvdownload.esa.int/ Login: esa / Password: ftp4esa
Info:
http://www.esa.int
http://new.livestream.com/ESA/cometlanding
Twitter: @ESA_Rosetta, @Philae2014, @esaoperations and @esascience
jumpjack
10-11-2014, 22:41
Animazione traiettorie pre - e post-atterraggio:
https://www.youtube.com/watch?feature=player_embedded&v=4a3eY5siRRk
Sequenza di attracco/atterraggio:
https://www.youtube.com/watch?v=YoqokoZkviM
jumpjack
10-11-2014, 22:57
https://jumpjack.files.wordpress.com/2014/11/sequenza.png
Grande jump, e complimenti per il modello... eheh bellissimo! :cincin:
Non so quanto riuscirò a seguire domani, ma un occhio lo butterò senz'altro e po la sera rivediamo tutto! :D
Peccato per la storia dell'esclusiva sulle immagini, se è proprio così... strano però. Mi chiedo comunque, dato partecipa anche la NASA tramite il Caltech/JPL, se la cosa valga anche per loro dato che per legge tutto il contenuto prodotto da missioni NASA sia interne che partecipate debba essere di dominio pubblico e senza restrizioni... terrei quindi d'occhio anche il portale http://rosetta.jpl.nasa.gov/. ;)
+Benito+
12-11-2014, 08:15
E' corretta una velocità di fuga di circa 18 m/s?
jumpjack
12-11-2014, 08:29
Assolutamente no, è UN metro al secondo, ha una gravità di 1/1000 della terra.
https://it.wikipedia.org/wiki/Rosetta_(sonda_spaziale)
Cmq sembra che il motore di trattenuta non sia utilizzabile! :(
+Benito+
12-11-2014, 09:05
ben per quello lo chiedevo. Non ero sicuro delle unità di misura per stimare la vf, senza motore sarà ormai quasi impossibile riuscire ad avvitare i piedi...c'è da sperare nell'ordine che non voli via e che non rimanga in una posizione completamente inutile.
P.S. 1/10000 non 1/1000, è 1 mm/s^2
La vf è circa 0.5 m/s
jumpjack
12-11-2014, 09:33
La rete mi ha piantato sul più bello... comunque grazie a Twitter ho avuto la conferma dell'avvenuta separazione del lander Philae!:)
Adesso è sulla rotta di atterraggio; il viaggio richiederà circa 7 ore, la conferma di avvenuto atterraggio dovrebbe arrivare intorno alle 17.00 ora italiana.
Però verso le 13.00 dovrebbero arrivare le prime immagini.
jumpjack
12-11-2014, 09:41
Telemetrie in diretta!
http://www.dlr.de/next/desktopdefault.aspx/tabid-9492/16405_read-40164/
http://www.musc.dlr.de/philae/telemetrie.html
Però non trovo la legenda...
Potrebbe essere in questo PDF, ma a me non si scarica!
ftp://ftp.irit.fr/IRIT/CSC/4218.pdf
+Benito+
12-11-2014, 10:11
lo scetticismo regna sovrano in sala controllo missione...
jumpjack
12-11-2014, 10:32
in attesa di...
11:53 Arrivo a terra della conferma di comunicazione stabilita tra Philae e Rosetta e della possibilità di Philae di comunicare con la Terra tramite Rosetta. Le sonde resteranno in contatto radio diretto fino a 90 minuti dopo l'atterraggio
jumpjack
12-11-2014, 10:37
lo scetticismo regna sovrano in sala controllo missione...
Anche nella mia testa... :(
Pretendere di effettuare un rendez-vous (*) nello spazio senza motori di manovra, affidandosi solo alla gravità.... :rolleyes:
Ci vogliono soldi per una missione così, non si può fare con gli spiccioli che ti ritrovi nelle tasche del cappotto.
L'unico aspetto positivo è che, anche se Philae non atterrerà, comunque Rosetta resterà in orbita per un anno e raccoglierà dati importantissimi e immagini spettacolari; probabilmente vedremo persino la cometa spaccarsi in due!
Ma atterrare sarebbe stato un miracolo già prima... adesso, senza motore di trattenuta, dovrebbe venire il padreterno in persona a tenere Philae appiccicato alla cometa...
Mi chiedo se e per quanto Philae resterà in orbita intorno alla cometa una volta "rimbalzato"; sarà comunque un evento interessante da vedere: le telecamere di Rosetta saranno puntate sulla sonda!
(*) Non si può definire "atterraggio" l'ancoraggio di una sonda a un oggetto praticamente privo di gravità. Sarebbe come dire che la Soyuz atterra sull'ISS...:rolleyes:
jumpjack
12-11-2014, 10:45
10 minuti al ripristino del contatto radio...
Chissà se si vedrà anche dalle telemetrie, ferme ora a 8:49 UTC (distacco Philae avvenuto a 9:03 UTC):
http://www.dlr.de/next/desktopdefault.aspx/tabid-9492/16405_read-40164/
jumpjack
12-11-2014, 11:05
Azz... 10 minuti e nessuna notizia!
@ESA_Rosetta, @Philae2014, @esaoperations and @esascience
jumpjack
12-11-2014, 11:08
"Acquiring Of Signal" confermato!
Rirpistinati i contatti con le sonde dopo i previsti 100 minuti di silenzio radio.
non mi carica le pagine della diretta... :(
jumpjack
12-11-2014, 13:39
"We've started to receive science data".
SHIVA shows, that separation ok.
"We've all data, we've hoping for".
"Everything is coming as expected".
"At 15h CET, we've a lot more to show you".
webcast:
ESA:
http://new.livestream.com/esa/cometlanding
NASA:
http://www.nasa.gov/multimedia/nasatv/index.html
qualcosa in diretta anche su Rai Scuola:
http://www.raiscuola.rai.it/palinsesto.aspx
speriamo vada tutto bene
jumpjack
12-11-2014, 14:20
Arrivata la prima immagine "Farewell" ("addio") scattata da Philae mentre si sganciava.
10:04:12 Lander*(ÇIVA)*obtains*first*images*of*Orbiter*(FAREWELL1)
10:06:17 Lander*(ÇIVA)*obtains*seconds*images*of*Orbiter*(FAREWELL2)
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=35353.0;attach=620346;image
+Benito+
12-11-2014, 14:23
rimane la speranza arpioni. La massa del lander è piccola, ma se vengono sparati e il suolo non è duro, potrebbero essere sufficienti a trattenerlo anche in caso di rimbalzo. Non conosco i dettagli, ma la sola "fucilata" dovrebbe rallentare in maniera non irrilevante il lander...
jumpjack
12-11-2014, 14:49
Attenzione alle fesserie ANSA che rimbalzeranno su tutti i giornali....
http://www.ansa.it/scienza/notizie/rubriche/spazioastro/2014/11/12/rosetta-si-e-separata-dal-lander-philae_181eba67-e87b-479f-9a1b-275659355d60.html
Nella notte era stato infatti rilevato un problema nella possibilità di attivare il sistema di discesa che impedisce al lander di rimbalzare sul suolo della cometa al momento dell'atterraggio. In particolare sembra non funzionare il piccolo motore a razzo che si trova sul 'tetto' del lander e che deve entrare in azione a circa 40 minuti prima che Philae si posi sulla cometa, per rendere la manovra più morbida.
Nell'ultima fase della discesa il 'carrello' di Philae libera infatti degli arpioni collegati a cavi di 45 metri (ma quando mai: sono due metri e mezzo), mentre il piccolo motore contrasta la spinta portando il veicolo verso l'alto (ma chi l'ha detto? Il motore è sul tetto, e spinge la sonda VERSO la cometa, che ha 1/10.000 di gravità terrestre, troppo poca per attirare stabilmente la sonda) e mantenendo i cavi in tensione, mentre un altro dispositivo li riavvolge lentamente fino al momento in cui le zampe toccano il suolo(ma l'hanno letto il materiale per la stampa o no??? il contatto delle zampe col suolo innesca il lancio dell'arpione)
IN REALTA':
http://articles.adsabs.harvard.edu/cgi-bin/t2png?bg=%23FFFFFF&/seri/ESASP/0524/600/0000239.000&db_key=AST&bits=4&res=100&filetype=.jpg
One harpoon (the default unit) shall be fired automati-
cally upon touchdown of the ROSETTA Lander on the
comet nucleus. The firing of the harpoon is triggered by
a touchdown signal generated by the Landing Gear. The
anchor cable is pulled out from a cable magazine which
is mounted beside the expansion cylinder. Immediately
after the firing the Rewind System is operated automati-
cally to spool up the cable and tighten the Lander to the
comet surface. The tightening force is commandable in
eight steps. A freewheeling mechanism maintains the
cable tension after the rewind actuator is switched off. A
motor-driven unlocking clutch allows to release the
cable tension. An identical second harpoon is available
in case of failure of the default unit.
jumpjack
12-11-2014, 14:50
Riuscite a scaricare questi file? (io no)
ftp://ftp.iwf.oeaw.ac.at/pub/schwingenschuh/ROSETTA_Konrad/Lander/ulamec2007-pdf-Capabilities%20of%20Philae,%20the%20Rosetta%20Lander%20-space-science-rev.pdf
http://www.esmats.eu/esmatspapers/pastpapers/pdfs/2003/thiel.pdf
ftp://ftp.mpe.mpg.de/pub/thiel/Expansion_System_Data_101001.doc
jumpjack
12-11-2014, 14:58
Prima photo fatta a Philae!
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=35353.0;attach=620421;image
The_Fragger
12-11-2014, 14:58
Riuscite a scaricare questi file? (io no)
ftp://ftp.iwf.oeaw.ac.at/pub/schwingenschuh/ROSETTA_Konrad/Lander/ulamec2007-pdf-Capabilities%20of%20Philae,%20the%20Rosetta%20Lander%20-space-science-rev.pdf
http://www.esmats.eu/esmatspapers/pastpapers/pdfs/2003/thiel.pdf
ftp://ftp.mpe.mpg.de/pub/thiel/Expansion_System_Data_101001.doc
Riuscito a scaricarli senza problemi, li condivido tramite qualche altro sito?
PS: vi sto seguendo con attenzione, e sto sentendo la conferenza (Y)
jumpjack
12-11-2014, 15:09
Sì magari, mettili su qualche sito!
Ecco intanto la prima foto di Philae:
https://mobile.twitter.com/ESA_Rosetta/status/532547063607984128/photo/1
E un'immagine "tecnica":
http://central.oak.go.kr/repository/journal/12549/HGJHC0_2013_v14n3_237_f001.jpg
http://central.oak.go.kr/search/detailarticle.jsp?article_seq=12549&tabname=abst&resource_seq=null&keywords=null
The_Fragger
12-11-2014, 15:14
https://drive.google.com/folderview?id=0B6sHInufToy1cVBFNHRiaUhXTDg&usp=sharing (File Rosetta ESA)
jumpjack
12-11-2014, 15:23
Hai scritto al contrario ;-)
File Rosetta ESA (https://drive.google.com/folderview?id=0B6sHInufToy1cVBFNHRiaUhXTDg&usp=sharing)
Però dall'ufficio non vedo manco questo, perfetto.
Meno male che sono le quattro e mezzo, addioooo ;-)
The_Fragger
12-11-2014, 15:37
Hai scritto al contrario ;-)
File Rosetta ESA (https://drive.google.com/folderview?id=0B6sHInufToy1cVBFNHRiaUhXTDg&usp=sharing)
Però dall'ufficio non vedo manco questo, perfetto.
Meno male che sono le quattro e mezzo, addioooo ;-)
eheheh :doh:
Hai ragione, comunque aperta la finestra....risposta attesa per le 17:02! :sperem:
jumpjack
12-11-2014, 16:03
Hai scritto al contrario ;-)
File Rosetta ESA (https://drive.google.com/folderview?id=0B6sHInufToy1cVBFNHRiaUhXTDg&usp=sharing)
Però dall'ufficio non vedo manco questo, perfetto.
Meno male che sono le quattro e mezzo, addioooo ;-)
tutta 'sta fatica... e poi in nessuno è scritto come funzionano le viti sulle zampe! :muro:
Solo gli arpioni sono spiegati
jumpjack
12-11-2014, 16:05
Che cu*o, sono riusciti comunque ad atterrare anche senza motore!!
YEAH! :D
jumpjack
12-11-2014, 16:07
Philae Lander @Philae2014
Touchdown! My new address: 67P! #CometLanding
https://twitter.com/Philae2014/status/532564514051735552
jumpjack
12-11-2014, 16:12
ESA Rosetta Mission @ESA_Rosetta · 3m 3 minutes ago
RT @esaoperations: RECEIPT OF SIGNAL FROM SURFACE. receiving signals from @Philae2014 on surface of comet #67P/CG #cometlanding
https://twitter.com/ESA_Rosetta/status/532565558051749888
jumpjack
12-11-2014, 16:15
Le telemetrie sembrano dire che è saldamente ancorata al suolo:
Confirmed on the surface and has telemetry, harpoons rewound. legs compressed!
...oppure che è a zampe per aria con gli arpioni riavvolti e le gambe avvitate. :sofico:
+Benito+
12-11-2014, 16:19
ottimo!!
jumpjack
12-11-2014, 16:31
Unica immagine per ora disponibile
https://jumpjack.files.wordpress.com/2014/11/philae.jpg
jumpjack
12-11-2014, 16:37
Foto fatta dal lander appena dopo il distacco:
https://jumpjack.files.wordpress.com/2014/11/lander.jpg
jumpjack
12-11-2014, 16:44
Atterraggio morbidissimo, l'ammortizzatore si è accorciato di soli 4 cm.
PERO'
le zampe non si sono avvitate al suolo!!! :eek:
La sonda è solo appoggiata! (e probabilmente tenuta in sede dai soli arpioni)
sbaglio o stanno ancora decidendo se rifare l'arpionaggio?
ma non sarebbe pericoloso?
jumpjack
12-11-2014, 16:51
sbaglio o stanno ancora decidendo se rifare l'arpionaggio?
ma non sarebbe pericoloso?
Hanno parlato di "anchor", non di "harpoon", quindi credo che gli arpioni siano stati sparati ma le zampe non si siano avvitate.
Comunque hanno anche detto che tra un'ora dovrebbe arrivare la prima immagine dalla superficie della cometa.
The_Fragger
12-11-2014, 16:53
https://www.youtube.com/watch?v=PUpSVxoCcik
Video ufficiale con musica dei Vangelis ;)
Hanno parlato di "anchor", non di "harpoon", quindi credo che gli arpioni siano stati sparati ma le zampe non si siano avvitate.
Comunque hanno anche detto che tra un'ora dovrebbe arrivare la prima immagine dalla superficie della cometa.
ah ok
comunque li vedo un po' preoccupati e carte alla mano
sperem
edit: nooo, gesticola cacchio nooo, spiegateci tutto
jumpjack
12-11-2014, 17:18
ah ok
comunque li vedo un po' preoccupati e carte alla mano
sperem
edit: nooo, gesticola cacchio nooo, spiegateci tutto
Mannaggia a Tito Stagno e all'ansia da annuncio-di-atterraggio... :muro:
jumpjack
12-11-2014, 17:23
Twitter: "I'm on the surface but my harpoons did not fire. My team is hard at work now trying to determine why."
Confermato che nè l'arpione principale nè quello di riserva sono stati lanciati.
https://twitter.com/ESA_Rosetta/status/532579871202238464
Però un'ora fa:
MT @esaoperations: Harpoons confirmed fired & reeled in. Flywheeel now be switched off. @Philae2014 is on the surface of #67P #CometLanding :muro:
jumpjack
12-11-2014, 18:00
Prima immagine della sequenza di atterraggio, altre attese tra mezz'ora:
https://jumpjack.files.wordpress.com/2014/11/b2qidzhieaaby43.jpg
jumpjack
12-11-2014, 18:03
Quella in alto a destra è ovviamente un'astronave aliena in agguato sulla cometa. :O
jumpjack
12-11-2014, 18:24
Conferenza stampa alle 19:30:
http://rosetta.esa.int/
jumpjack
12-11-2014, 18:40
Terza variante:
Philae is the comet's surface, but the harpoons are deployed as planned. Two of the three foot screws onto the surface
https://translate.google.com/translate?sl=fi&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Ftwitter.com%2FIlmaTiede%2Fstatus%2F532596865389576194&edit-text=
Veramente ridicolo.
Vediamo se adesso ESA capisce l'importanza di condividere i dati invece di "fare i segreti"
jumpjack
12-11-2014, 19:10
Quarta variante:
Drat. Apparently, the harpoons DIDN'T fire and the lander is in an unstable situation. This is affecting data transmission
https://twitter.com/stevendiz/status/532609989689749504
jumpjack
12-11-2014, 19:13
Conferenza iniziata.
Siamo atterrati.
Sulla cometa giusta. :-)
Il lander funziona.
Stanno analizzando i dati.
Devono essere cauti perchè sono appena agli inizi della missione che durerà mesi.
jumpjack
12-11-2014, 19:14
Parla ora Mottola, responsabile telecamera di discesa.
Mostra questa foto, e fine.
https://jumpjack.files.wordpress.com/2014/11/b2qidzhieaaby43.jpg
Poi la parola passa a...
jumpjack
12-11-2014, 19:16
boh, Paolo Ferri?
Dice che è molto complicato capire cosa è successo durante l'atterraggio. :confused: :muro:
Poi mi si è interrotto lo straming...
jumpjack
12-11-2014, 19:21
Abbiamo ricevuto dati a terra, e questo ok.
Però il lander non è ancorato con gli arpioni.
Non sanno perchè, stanno cercando di capire cosa è successo.
Riceviamo dati molto buoni continuamente, gli strumenti sono molto belli e fichi,
abbiamo un sacco di dati
MA
alcuni di questi dati sembrano dire che il lander è rimbalzato leggermente e FORSE ha iniziato a ruotare su sè stesso perchè il volano stabilizzatore era già stato spento (così sembra di poter dedurre dalle variazioni di illuminazione dei pannelli solari).
Due ore dopo la rotazione si sarebbe fermata.
Poi però la sonda è riatterrata.
(e ride pure...) :doh:
jumpjack
12-11-2014, 19:25
No, è ora che parla Paolo Ferri, prima era Stephan Ulamec.
Dicono che ora Rosetta è sotto l'orizzonte e non può comunicare; veramente io sapevo che aveva copertura h24 grazie alla DeepSpaceNetwork... mah.
Domattina si ristabilirà il contatto.
Non è che si capisca molto se parla del contatto lander-orbiter o lander-terra...
Domani alle 14.00 italiane ci dovrebbe essere una conferenza stampa ufficiale.
jumpjack
12-11-2014, 19:27
Conferenza stampa finita, arrivederci e grazie, e manco un'immagine.
Mavaffa***va
ci tengono sulle spine fino a domani con un "all is well" TERRIFICANTE
ah ah
Dai dai, intanto ottimo risultato per ora... due atterraggi è meglio che uno! :D :)
Possiamo disquisire sulle differenze di PR tra NASA/JPL ed ESA ma l'importante è che Philae stia bene e gli strumenti stiano raccogliendo dati. Una missione così complicata ha i suoi rischi e per come è andata fin'ora c'è da essere soddisfatti!
Anche nel caso il lander non fosse "arpionato" su 67P gran parte degli esperimenti potranno essere comunque eseguiti... aspettiamo domani.
massì, e anche se il lander fosse capovolto o infilzato nella polvere fino a metà, Rosetta è talmente vicina che ci riempirà di dati lo stesso
http://oi61.tinypic.com/ifyc7b.jpg (http://sci.esa.int/science-e-media/img/f2/Rosetta_CIVA_20141007_selfie_at_comet.png)
clicca per ingrandire
Dall'account twitter di ROMAP (Rosetta Lander Magnetometer and Plasma Monitor):
https://twitter.com/Philae_ROMAP/status/532677268741824512
Philae_ROMAP @Philae_ROMAP
magnetic field analysis revealed 3 landings at 15:33, 17:26 and 17:33 UTC
Litsa @LitsaPavlidou 4 minuti fa
@Philae_ROMAP does this mean #Philae is not stable on the surface?
Philae_ROMAP @Philae_ROMAP
@LitsaPavlidou is stable now!
Quindi 3 "accometaggi" ( :mbe: :fagiano: ), il primo bounce forse per la mancata attivazione degli arpioni, il secondo ad altezza più bassa e infine l'ultimo con il contatto definitivo, probabilmente stabilizzato dagli ancoraggi a penetrazione.
non resta che aspettare fino alle 14 quindi per avere notizie ufficiali?
complimenti in ogni caso a tutte le persone coinvolte!
+Benito+
13-11-2014, 07:57
finchè non vedo non credo...
jumpjack
13-11-2014, 08:37
Dall'account twitter di ROMAP (Rosetta Lander Magnetometer and Plasma Monitor):
https://twitter.com/Philae_ROMAP/status/532677268741824512
Philae_ROMAP @Philae_ROMAP
magnetic field analysis revealed 3 landings at 15:33, 17:26 and 17:33 UTC
Il campo magnetico di cosa?? Della cometa??? :confused:
Comunque leggo anche che stanno cercando di capire se il lander è orizzontale, sdraiato o a zampe all'aria, dall'intensità dei segnali radio ricevuti da Rosetta! :muro:
Immagini, servono IMMAGINI!! :muro:
+Benito+
13-11-2014, 08:44
spero impareranno dall'errore, è una gestione semplicemente scandalosa della comunicazione. Definirli principianti improvvisati è far loro un complimento.
jumpjack
13-11-2014, 09:16
Il campo magnetico di cosa?? Della cometa??? :confused:
Mi rispondo da solo: :)
both the lander and the orbiter generate small magnetic fields of their own, due to the electronic circuits inside the spacecraft. These magnetic fields create perturbations in the data that the scientists normally remove in order to analyse the purely natural magnetic fields from the comet and the solar wind. However, on 12 November, these perturbations can be analysed to tell what is happening to the lander as it slowly drops towards the surface of 67P/C-G.
http://blogs.esa.int/rosetta/2014/11/11/tracking-philaes-descent-with-magnetic-data/
Lander e orbiter generano piccoli campi magnetici a causa dei circuiti di bordo. Questi campi magnetici generano perturbazioni nei dati, che normalmente gli scienziati filtrano via per analizzare i campi magnetici naturali dei corpi celesti visitati. Tuttavia, durante l'atterraggio queste perturbazioni [sono state] sfruttate per capire cosa stava succedendo al lander.
jumpjack
13-11-2014, 09:25
C'è chi ipotizza uno strato di polvere spesso 2 metri che ricopre la cometa...
Dust/snow layer seems to be 2-3 meter thick, because landslide A, is a clear avalanche of 100x11 meter estimated depth 2-3 meter.
http://is.gd/itocit
Personalmente penso che non solo sia polvere, ma sia anche "polvere non aggregata", per via del decimillesimo di gravità: immaginate sassolini, ghiaccio, polvere e microdetriti che svolazzano nel vapore acqueo prodotto dall'evaporazione del ghiaccio, non riescono a ricadere subito per via della bassissima gravità, e quindi restano in orbita PER MESI intorno al nucleo roccioso; alcuni vengono spazzati via dal vento solare e creano la coda, ma altri, alla fine, piano piano, molto piano, si depositano.
Io immagino una consistenza tipo cenere vulcanica, se non addirittura schiuma da bagno. Secondo me sono più che altro sassolini che "orbitano a quota zero" intorno al nucleo, piuttosto che "terreno".
Immaginate cosa può voler dire "atterrare" su uno strato del genere spesso 2 metri!
Oltretutto sulla cometa il lander pesa appena 10g.... ma ha comunque una massa inerziale di 100 chili!
:mbe:
+Benito+
13-11-2014, 09:36
è possibile che sia coperta di "zucchero a velo", che sembra duro ma invece non è e che il lander sia affondato in questa polverina. Se fosse successo, la cosa sarebbe stata vista sicuramente dalla sonda madre che avrebbe fotografato la nuovla di polvere.
Ma porca pupazza come si fa a non divuolgare nè dati nè foto? Sono fuori di melone...
jumpjack
13-11-2014, 10:17
Prima immagine dalla superficie!
http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/11/welcome_to_a_comet/15048351-1-eng-GB/Welcome_to_a_comet_node_full_image_2.jpg
+Benito+
13-11-2014, 10:50
solo a me quello a sinistra sembra uno dei tre piedi? Mi sa che è coricato su un fianco... e sembra roccia.
jumpjack
13-11-2014, 11:43
solo a me quello a sinistra sembra uno dei tre piedi? Mi sa che è coricato su un fianco... e sembra roccia.
Ovvio che è un piede.
Il problema è cosa sia quel "palo" in basso a destra: un'antenna CONSERT come dice qualcuno, o un cavo teso di un arpione?
Però oggi la QUINTA variante dice che gli arpioni NON sono stati sparati...
Dicono anche che ha fatto due o forse 3 rimbalzi, spostandosi di 1 km dal punto di contatto iniziale (e la cometa è larga 2 o 3 km....), e che potrebbe essere adagiato su un fianco, visto che delle 7 immagini scattate tutte intorno al lander... una inquadra il cielo! :doh:
Tecnicamente questo tipo di atterraggio si definisce "un bordello". :sofico:
In aggiunta, su dodici ore di durata del giorno, i pannelli risultano illuminati per 1,5 ore. :(
Le batterie, senza caricarsi, hanno 64 ore di autonomia.
jumpjack
13-11-2014, 14:01
Arrivate un po' di immagini... tra cui:
http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/11/descent_to_the_surface_of_a_comet/15050365-1-eng-GB/Descent_to_the_surface_of_a_comet.gif
http://www.esa.int/spaceinimages/Missions/Rosetta/%28class%29/image
vista la conferenza, la strategia ora potrebbe essere di attivare gli strumenti che consumano di meno per poi tentare in extremis di smuovere il lander e magari fargli fare un altro voletto e il quarto atterraggio :D in un punto con più luce; io spero però che riescano a tenerlo lì semi ibernato in modo da caricare le batterie per poi riaccenderlo il prossimo 13 Agosto quando la cometa è più vicina al Sole; voglio dire, se c'è da scegliere tra tentare il tutto per tutto ora o il prossimo Agosto, segliete Agosto per favore!
+Benito+
13-11-2014, 14:41
in effetti l'impressione è che a terra non ci sia proprio guardando meglio la foto. Purtroppo philae non può essere mosso in alcun modo, non ha organi mobili nè motori...se si fosse almeno agganciato con un arpione tanto da non volare via sarebbe già buono.
Non mi è chiaro, comunque, come funzionino gli arpioni: se quella è roccia, pensare che una fiocina di...1 kg? sparata da un robottino di 100kg si possa conficcare mi sembra utopico.
jumpjack
13-11-2014, 14:47
Io invece devo ancora capire che cazzarola è successo ai due arpioni!
La SESTA variante dice che NON sono stati sparati ma sono state attivate le bobine su cui sono avvolti.
Chemminchia vuol dire??? :muro:
E poi ho anche appena scoperto che il carrello di atterraggio non è solo un ammortizzatore passivo: è attivo! Può essere mosso! :mbe:
Ma non riesco a scaricare quel cavolo di documento di specifica... voi ci riuscite?
Non mi ricordo manco più il link... forse era in questo FTP?
ftp://ftp.iwf.oeaw.ac.at/pub/schwingenschuh/ROSETTA_Konrad/EMC2012/
jumpjack
13-11-2014, 14:55
Non mi è chiaro, comunque, come funzionino gli arpioni:
www.esmats.eu/esmatspapers/pastpapers/pdfs/2003/thiel.pdf
Altri documenti tecnici che ho trovato:
Manuale utente di Philae (davvero! :sofico: ): http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=35353.0;attach=620585 (allegato del forum)
Purtroppo è solo una vecchia bozza semivuota...
Capacità tecniche del lander: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=35353.0;attach=620585 (allegato del forum)
Rosetta Lander Landing Gear Requirement Specification: ftp://ftp.estec.esa.nl/pub2/sci-spd/rosetta2/lgr/RequirementSpec.doc
Presentazione tecnica sul lander (powerpoint): http://solarsystem.nasa.gov/docs/5-3_Witte_Philae-LanderTouchdownDynamicsRevisited-Tests-Upcoming-Landing-Preparations.pptx
Molti però non riesco a scaricarli, qualcuno ci riesce e puo' metterli da qualche altra parte?
momo-racing
13-11-2014, 16:57
io capisco la particolarità della missione ma non si sono lasciate un po' troppe cose "al caso" per una missione che se le cose vanno male si sono giusto buttati via 10 anni?
+Benito+
13-11-2014, 17:30
mi pare che si sia trattato di una missione a basso costo e studiata in origine per un altro obiettivo, poi cambiato a seguito del fallimento di un vettore che non permetteva più di centrare la finestra di lancio.
In effetti, se alla nasa sono riusciti a portare la panda su marte coi cavi e i retrorazzi, in esa si stanno facendo bagnare il naso mica poco.
Leggo che sembra che sia rimbalzato due volte, la prima per 1 km (!) quasi perdendosi nello spazio, e la seconda meno, e che attualmente giace ben lontano da dove avrebbe dovuto (tipo 1 km di distanza).
Il "filo" mi sembra ragionevole che sia il CONSERT che appoggia con la punta sulla superficie
Gli arpioni non hanno funzionato a causa del propellente che si è dimostrato essere inaffidabile nel vuoto (e dopo 10 anni...).
In pratica come componentistica hanno ciccato di brutto:
- Il gas compresso non ha funzionato
- Gli arpioni non hanno funzionato
- Un giroscopio si è consumato e un altro ha funzionato fuori specifica
E' un successo che con tutto ciò sia riuscito almeno a schiantarsi e mandare una foto
P.S. tutta roba tedesca, per inciso
jumpjack
13-11-2014, 18:06
Chi vuole farsi una scorpacciata di documenti tecnici? :)
https://www.google.it/search?q=site%3Aftp%3A%2F%2Fftp.estec.esa.nl%2Fpub2%2Fsci-spd%2Frosetta2%2Flgr%2F+doc&oq=site%3Aftp%3A%2F%2Fftp.estec.esa.nl%2Fpub2%2Fsci-spd%2Frosetta2%2Flgr%2F+doc&aqs=chrome..69i57j69i58.3600j0j4&sourceid=chrome&es_sm=93&ie=UTF-8#q=site:ftp:%2F%2Fftp.estec.esa.nl%2Fpub2%2Fsci-spd%2Frosetta2%2Flgr%2F+*
Io alla cartella sito FTP non riesco ad accedere... ma google sì. :)
jumpjack
13-11-2014, 18:34
Molto molto interessante il documento RequirementSpec.doc !!
Angolazioni massime accettabili del lander in caso di malfunzionamento del motore superiore:
25° (invece che 18) tra asse Z e verticale del terreno
32° (invece che 18) tra direzione della velocità e verticale del terreno
Peso massimo del carrello di atterraggio: 8 kg
Distanza minima arpione-terreno per poter raggiungere la velocità minima richiesta: 60 mm.
Forze e coppie risultanti sul lander dall'utilizzo dei vari strumenti:
Trivella "SD2": 10 N di forza, 5 Nm di coppia.
Dispiegamento ROMAP (sensore magnetico): 200g di peso "spostati"
Dispiegamento MUPUS PEN: 1000 g
Capacità di ritenuta di ogni arpione: regolabile tra 1 e 30 N.
Le antenne CONSERT sono lunghe 80 cm e larghe 5 mm
La fotocamera ROLIS sotto al lander ha una profondità di campo di 80mm e una visuale ottimale a 300 mm di distanza.
Gli arpioni sono in asse col baricentro del lander per evitare che il loro lancio alteri l'orientamento del lander.
Il volano ha una capacità stabilizzante di 5 Nms
Il motore a gas genera un impulso di 5 secondi e di 5 Ns per contrastare lo sparo dell'arpione.
Il riavvolgimento dell'arpione richiede 5 secondi.
Sarebbe interessante trovare anche il documento "Anchor sub-system specification, RO-LAS-SP-3101" e RO-LAN-RD-3111 e RO-EST-RS-3001/EID A
Oddio una missione mai tentata e da 1,4 miliardi definirla a basso costo e con molte cose lasciate andare al caso mi sembra un tantino tirata... mentre è vero che l'obbiettivo iniziale era la cometa 46P/Wirtanen ma che a causa dell'incidente del volo 157 dell'Ariane 5 (il primo Ariane 5 in versione ECA, v-157, 11/12/2002) fu cambiato con 67P, per via dell'impossibilità di effettuare il randeveuz con la nuova finestra di lancio.
http://www.spacedaily.com/news/rosetta-03c.html
Questo però non ha cambiato sostanzialmente la natura e gli obbiettivi della missione.
Cmq... telemetria da Philae:
http://www.musc.dlr.de/philae/telemetrie.html
Per ora, a parte la questione dell'insolazione nel nuovo sito
jumpjack
13-11-2014, 20:52
Oddio una missione mai tentata e da 1,4 miliardi definirla a basso costo e con molte cose lasciate andare al caso mi sembra un tantino tirata...
Boh, io non riesco a trovare un senso nel cercare di far atterrare una sonda senza motori di manovra, solo per gravità, su un oggetto che nessuno ha mai visto prima da vicino, che potrebbe essere duro come il granito o soffice come la neve. Infatti quando ho letto dei MILIARDI sono rimasto sbigottito, io ero rimasto alla decisione della NASA di fare solo missioni a basso costo, max 2-300 milioni di euro!
Comunque ho appena letto una SETTIMA variante che dice che gli arpioni HANNO sparato... e sarebbero proprio loro il motivo del "rimbalzo": era previsto che il motore si accendesse per 5 secondi durante il lancio degli arpioni (e di questo ho letto conferma nei documenti) per contrastare il rinculo.... ma il motore era spento! Praticamente gli arpioni non hanno fatto presa, e quindi hanno fatto solo danno, spingendo via la sonda! :doh:
Cmq proprio non capisco perchè hanno frenato il volano immediatamente dopo l'atterraggio: se continuava a girare cosa succedeva di male?!? Ho letto proprio così, non l'hanno spento, l'hanno frenato.... quindi, in realtà, essendo la sonda in volo invece che a terra... non hanno frenato il volano: hanno messo in rotazione la sonda!
Che, peraltro, era GIA' in rotazione al momento del distacco! Si vede dall'animazione di discesa. Perchè mai stava ruotando? Come fai ad atterrare mentre giri su te stesso?
Mi chiedo che coppia esercitano i cuscinetti del volano sulla sonda, e se è sufficiente a farla ruotare così velocemente già subito dopo il distacco.
Cmq... telemetria da Philae:
http://www.musc.dlr.de/philae/telemetrie.html
Purtroppo è roba "di repertorio", si ferma al 12 novembre,
...Cmq proprio non capisco perchè hanno frenato il volano immediatamente dopo l'atterraggio: se continuava a girare cosa succedeva di male?!? Ho letto proprio così, non l'hanno spento, l'hanno frenato.... quindi, in realtà, essendo la sonda in volo invece che a terra... non hanno frenato il volano: hanno messo in rotazione la sonda!
A 800 milioni di kilometri dalla terra i comandi trasmessi impiegano 40 minuti ad andare e la risposta della sonda altri 40 minuti a tornare (spannometricamente).
La sonda ha eseguito il programma ma non è possibile avere il feedback di quello che succede in realtà, viene inviata la sequenza di comandi, si attende un'ora e mezza e si leggono le risposte.
jumpjack
13-11-2014, 21:58
A 800 milioni di kilometri dalla terra i comandi trasmessi impiegano 40 minuti ad andare e la risposta della sonda altri 40 minuti a tornare (spannometricamente).
La sonda ha eseguito il programma ma non è possibile avere il feedback di quello che succede in realtà, viene inviata la sequenza di comandi, si attende un'ora e mezza e si leggono le risposte.
Lo so, sono 26+26 minuti e la sonda è autonoma e preprogrammata... ma che c'entra con quello che ho detto?
Il programma di bordo prevedeva di frenare il volano automaticamente appena atterrati: perchè? :confused: Quali controindicazioni ci sono in un volano che gira dentro un lander atterrato? Invece controindicazioni ci sono nel frenare un volano in un lander rimbalzato!
Sembra quasi che qualcuno abbia toppato un'analisi di criticità... :stordita:
Boh, io non riesco a trovare un senso nel cercare di far atterrare una sonda senza motori di manovra, solo per gravità, su un oggetto che nessuno ha mai visto prima da vicino, che potrebbe essere duro come il granito o soffice come la neve. Infatti quando ho letto dei MILIARDI sono rimasto sbigottito, io ero rimasto alla decisione della NASA di fare solo missioni a basso costo, max 2-300 milioni di euro!
No, il direttorato per le missioni scientifiche NASA ha un programma di missioni a basso costo (come Mars Scout) e di altre cosiddette "flagship" il cui costo medio varia tra i 6-700 milioni (come New Horizons) e i 2,5 miliardi ad esempio di MSL.
E' assolutamente in linea con misisoni di questa complessità, e la più costosa ad oggi rimane sempre Cassini-Hyugens, conigunta NASA-ESA, con i suoi 3,2 miliardi.
Ragazzi, l'esplorazione e la ricerca scientifica costa... eppure questi miliardi non sono niente "per capita" in confronto ad altre spese sostenute dagli stati, soprattutto quando i costi vengono condivisi.
Comunque ho appena letto una SETTIMA variante che dice che gli arpioni HANNO sparato... e sarebbero proprio loro il motivo del "rimbalzo": era previsto che il motore si accendesse per 5 secondi durante il lancio degli arpioni (e di questo ho letto conferma nei documenti) per contrastare il rinculo.... ma il motore era spento! Praticamente gli arpioni non hanno fatto presa, e quindi hanno fatto solo danno, spingendo via la sonda!
Riporto dal thread NSF: http://forum.nasaspaceflight.com/index.php?topic=36067.0
A precisa domanda alla conferenza stampa di oggi all'ESOC:
Harpoons did not fire.
Harpoon sequence was triggered upon initial touchdown, but harpoons did not actually fire. But spools WERE activated, despite the fact that the harpoons had not fired.
Failure of harpoon firing still under investigation.
E ancora... a riepilogo:
- Lander bounced twice and thus landed three (3) times.
- First bounce likely sent lander substantial distance back into space. Bounce height is to be determined. First bounce lasted two hours.
- Lander likely has come to rest closer to the 'neck' of the comet, due to the comet rotating underneath Philae during the first major bounce.
- Solar panels are generating electrical power. Electrical levels within expectations.
- Communications are fully operational. Clear signals being received via Rosetta.
- Science sequence will have to be reworked.
- ÇIVA-P imaging device was in auto-mode during the bouncing. Shot many images. All images downloaded to earth. Images show mostly empty space or streaks. This is because of the bounce back into space.
- Likely ÇIVA-P will be commanded to perform a new sequence upon available communications window today.
- COSAC, CONCERT, PTOLEMY, ROMAP and ROLIS all got data during and after landing phase. Data was delivered to earth, via Rosetta, in good order.
- No drilling today. Harpoons failed to either fire or to anchor. Exact nature of failure is not yet fully understood. Without Philae being anchored to surface drilling is out of the question.
- Rosetta will be commanded to image the comet to help ascertain exact location of Philae on surface.
Dato che ormai se ne parla, riporto questa incredibile chicca di quel pozzo che è il TG4...
www.wired.it/scienza/spazio/2014/11/13/rosetta-tg4-medioevo
:muro: :doh:
https://twitter.com/Philae_MUPUS/status/532968586005217280
MUPUS on Philae @Philae_MUPUS
We will deploy the MUPUS penetrator for 2/3 of the max. length and then insert it. Should happen before midnight. Keep fingers crossed
Aggiungo che stanno valutando la possibilità di attivare il sistema di ancoraggio sui piedi del lander per provare a spostarlo in una posizione più favorevole con maggiore esposizione solare.
jumpjack
14-11-2014, 07:53
sì avevoletto quella cosa degli "spools"attivati senza sparare gli arpioni... ma mica ho capito che vuol dire!!???
Gli spools dovrebbero essere le bobine dove sono avvolti i cavi; un motore doveva riavvolgere i cavi dopo lo sparo.
Invece cosa sarebbe successo??
+Benito+
14-11-2014, 08:59
le bobine ho capito che sono l'innesco, ma il propellente non ha propulso.
jumpjack
14-11-2014, 13:15
Trivellazione "italiana" tramite strumento SD2 iniziata... ma è terminata la finestra-radio, si riapre stasera alle 22.00!!!
jumpjack
14-11-2014, 13:18
Conferenza stampa iniziata... ma la devo seguire tramite i post sui forum perchè in ufficio non si vede...
Scattate 85 immagini a terra dalla sonda, ma non ancora inviate. L'orbiter ha fotografato i rimbalzi del lander.
jumpjack
14-11-2014, 13:25
Non sanno se le batterie dureranno fino a stasera per scaricare i dati! :muro:
jumpjack
14-11-2014, 13:26
Vorrebbero sollevare il lander di quei pochi cm di cui è capace per fargli prendere un po' più di sole.
jumpjack
14-11-2014, 13:32
Il trapano potrebbe non riuscire a raggiungere la superficie perchè troppo lontana.
Forse riavvieranno il volano per dare una spintina al lander.
Ad esperimenti terminati, stasera, resteranno solo 20 Wh dei 100 disponibili ora nella batteria.
Proveranno a ruotare il lander per mettere alla luce un pannello più grande.
Forse proveranno a far fare un saltello al lander grazie allo stantuffo del carrello di atterraggio.
microcip
14-11-2014, 15:01
sembra che abbiano beccato delle geometrie sospette sulle foto inviate da Rosetta:
http://abload.de/img/20141114_83452_1-rosezts3f.jpg
http://abload.de/img/20141114_83452_2014-1ykscv.jpg
jumpjack
15-11-2014, 00:58
Roba da non crederci: nonostante la posizione impossibile, nonostante le batterie quasi scariche, nonostante tutto, Philae:
- ha completato tutti gli esperimenti scientifici
- si è alzato di 4 cm
-e' ruotato di 35°
-ha scattato nuove foto CIVAS(intorno) e ROLIS (sotto)
-e' riuscito a inviare a Rosetta tutti i dati raccolti!
Poi è "spirato". O meglio, si è addormentato a causa delle batterie scariche.
L'hanno anche quasi trovato: hanno fotografato il punto del primo rimbalzo; distante appena 10 metri dal punto di atterraggio previsto!
unico intoppo: non si è aperto il coperchio dello spettrometro... che quindi ha "misurato" il coperchio, rilevando titanio e alluminio o qualcosa del genere! :-)
Un pazzesco tecnomiracolo.
jumpjack
15-11-2014, 08:36
Alle 7.00 italiane è sorto il sole su Philae, alle 12 Rosetta gli passerà sopra...
Intanto che aspettiamo, ecco i grafici del magnetometro durante i touchdown:
http://www.igep.tu-bs.de/forschung/weltraumphysik/projekte/rosetta/comet_en.html
jumpjack
15-11-2014, 08:37
Individuato luogo del primo rimbalzo: https://twitter.com/elakdawalla/status/533385159564095488
jumpjack
15-11-2014, 08:50
http://blogs.esa.int/rosetta/files/2014/11/philae_landing_site_navcam_before_after.gif http://blogs.esa.int/rosetta/2014/11/14/philaes-first-touchdown-seen-by-rosetta/
scusate intervengo solo per dire: l'avete visto il servizio ANDATO IN ONDA su rete 4?
sono allibito e sconcertato.
sbudellaman
15-11-2014, 10:39
scusate intervengo solo per dire: l'avete visto il servizio ANDATO IN ONDA su rete 4?
sono allibito e sconcertato.
Io PURTROPPO l'ho visto. Posto un articolo col video affinchè tutti possano vedere quale gente IDIOTA ed IGNORANTE abbiamo a dirigere i telegiornali.
http://www.wired.it/scienza/spazio/2014/11/13/rosetta-tg4-medioevo/
+Benito+
15-11-2014, 11:41
c'è speranza che magari a cicli di qualche giorno di sole per qualche ora di lavoro lo possano riaccendere?
Ottime notizie da Philae, grandioso!
@tg4: si l'ho visto anch'io e postato già l'articolo di wired... medioevo! :muro: :cry:
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