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Old 12-02-2004, 19:43   #1
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[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).



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.



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.




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




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




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).




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

Sito ufficiale - Rosetta Science:

ESA - Rosetta Science


Altre missioni relative a comete:

- NASA - Deep Impact

- NASA - Stardust
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Ultima modifica di GioFX : 12-02-2004 alle 19:47.
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Old 12-02-2004, 19:48   #2
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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.


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.
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Old 12-02-2004, 19:50   #3
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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.



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.
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Old 12-02-2004, 19:53   #4
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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.
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Old 17-02-2004, 16:59   #5
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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.
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Old 17-02-2004, 21:01   #6
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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.
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Old 17-02-2004, 21:16   #7
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però dovrebbero fare un corso presso gli americani per trovare nomi decenti alle missioni
Rosetta powerd by intel centrino
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Old 17-02-2004, 22:45   #8
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Originariamente inviato da mrc
però dovrebbero fare un corso presso gli americani per trovare nomi decenti alle missioni
Rosetta powerd by intel centrino



Se leggevi si capiva il riferimento alla Stele di Rosetta, che ha permesso di conoscere a fondo la civiltà egizia.
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Old 20-02-2004, 16:22   #9
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Links missione:

- ESA - Rosetta Mission

- ESA - Rosetta Science

- ESA - Rosetta Scientific and Technical website

- ESA - Rosetta Journal - Multimedia (foto e video)
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Old 20-02-2004, 16:37   #10
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Questa missione mi ricorda un po' Armageddon...
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....
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Old 20-02-2004, 17:14   #11
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Originariamente inviato da Coyote74
Comunque da buon Ingegnere Aerospaziale non posso che essere felice della cosa.
Che fai di bello, lavori? Se si, dove?
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Old 20-02-2004, 17:18   #12
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Ma cosa continui ad aprire i thread che oramai non si riesce più a star dietro a tutti!
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Old 20-02-2004, 17:27   #13
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"piccoli" pannelli solari...



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Old 20-02-2004, 17:28   #14
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Crossposting...
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Old 20-02-2004, 17:29   #15
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Originariamente inviato da gpc
Ma cosa continui ad aprire i thread che oramai non si riesce più a star dietro a tutti!
Mmhh, e io che volevo aprirne giusto un altro pò...



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Old 20-02-2004, 17:29   #16
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Originariamente inviato da GioFX
Mmhh, e io che volevo aprirne giusto un altro pò...

Sei il Gik25 dell'astronomia
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Old 20-02-2004, 17:30   #17
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Originariamente inviato da gpc
Crossposting...
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Old 20-02-2004, 17:31   #18
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Originariamente inviato da gpc
Sei il Gik25 dell'astronomia


...et tecnologia aerospaziale, please!
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Old 20-02-2004, 17:32   #19
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Salve a tutti, oggi ho partecipato ad una conferenza con Guidoni organizzata dalla mia scuola, è stato interessante.
Byezz
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Old 20-02-2004, 18:53   #20
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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 Comunque ho intenzione di fare domanda presso l'Alenia e vediamo come va....
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