[Space] NASA - New Horizons: Pluto-Kuiper Belt Mission

[GioFX]

Sito ufficiale della missione: http://www.nasa.gov/mission_pages/newhorizons/main/

Sito della missione della John Hopkins University: http://pluto.jhuapl.edu/index.php


Missione

Primary Launch Window:
January 17 - February 14, 2006

Launch Vehicle:
Atlas V 551 first stage; Centaur second stage; STAR 48B solid rocket third stage

Location:
Cape Canaveral Air Force Station, Florida

Trajectory:
• To Pluto via Jupiter Gravity Assist (first 17 days of window)
• Direct to Pluto (last 12 days of window)

Secondary Launch Window:
February 2-15, 2007 ; puts New Horizons on a direct-to-Pluto trajectory with arrival in 2019-2020, depending on exact launch date.


The Voyage

Early Cruise: Assuming liftoff during the primary launch window in January 2006, the first 13 months include spacecraft and instrument checkouts, instrument calibrations, trajectory correction maneuvers, and rehearsals for the Jupiter encounter.

Jupiter Encounter: Closest approach scheduled to occur between Feb. 25- March 2, 2007. Moving about 47,000 miles per hour (about 21 kilometers per second), New Horizons would fly 3 to 4 times closer to Jupiter than the Cassini spacecraft, coming within 31.7-32.4 Jupiter radii of the large planet.

Interplanetary Cruise: activities during the approximately 8-year cruise to Pluto include annual spacecraft and instrument checkouts, trajectory corrections, instrument calibrations and Pluto encounter rehearsals.




Pluto-Charon Encounter

Arrival depends on launch date:

- Arrival via Jupiter: 2015-2017; direct to Pluto: 2018-2020
- At the earliest, current 1st graders will see New Horizons arrive at Pluto during the summer before 12th grade!




Into the Kuiper Belt

Plans for an extended mission include one to two encounters of Kuiper Belt Objects, ranging from about 25 to 55 miles (40 to 90 kilometers) in diameter. New Horizons would acquire the same data it collected at Pluto-Charon - where applicable - and follow a timeline similar to the Pluto-Charon encounter:

- Closest Approach - 4 weeks: object observations
- Closest Approach + 2 weeks: post-encounter studies
- Closest Approach + 2 months: all data returned to Earth

[GioFX]

New Horizons: First Mission to the Last Planet

BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: January 14, 2006

KENNEDY SPACE CENTER, Fla. (CBS) - Imagine the sun the size of a quarter - one inch across - on the goal line of the Rose Bowl.

The Earth, just 0.009 inches across, would be positioned around the three-yard line. Mighty Jupiter, just one tenth of an inch across, would be "orbiting" inside the red zone at the 15-and-a-half yard line and ringed Saturn would be just inside the 30. The outer gas giants, Uranus and Neptune, would be orbiting on the opponent's side of the field, 57 and 90 yards from the sun.

And what of frigid Pluto, circling the sun in a lopsided orbit at an average distance of 3.7 billion miles? The icy dwarf would be an invisible speck one thousandth-of-an-inch across 18 yards beyond the opponent's goal line. At that scale, light would move at two-tenths of an inch per second and it would take radio signals more than five hours, on average, to cross the field and reach the ninth planet. The nearest star would be some 460 miles from Pasadena.*

Now imagine sending a spacecraft from Earth, on the three-yard line, to Pluto more than 100 yards away. That's exactly what NASA plans to do Jan. 17 when it launches the nuclear-powered New Horizons probe on a $700 million mission to the only one of the solar system's nine traditional planets that has never been visited.

Given the mind-boggling distances involved, NASA is launching the small, 1,054-pound New Horizons probe atop one of the most powerful unmanned rockets in the U.S. inventory, a 20-story-tall, 1.2-million-pound Lockheed Martin Atlas 5 equipped with five strap-on boosters. Departing Earth at a record 36,000 mph, the spacecraft will cross the moon's orbit just nine hours after liftoff. It will cross the orbit of Mars, race through the asteroid belt and get to Jupiter in just 13 months for a velocity boosting gravity assist flyby that also will give the science team an opportunity to thoroughly test the probe's half-dozen instruments.

Even though its velocity will be 100 times faster than a jetliner throughout its long voyage, it will still take New Horizons, the fastest thing ever built by the people of planet Earth, more than eight additional years to reach Pluto and its moon Charon. Kids in the first grade today will be in high school, dating and learning to drive by the time the spacecraft reaches its target. Their parents will have voted in two presidential elections and Vince Young, the University of Texas quarterback who starred in this year's Rose Bowl game, will be facing the twilight of his professional football career.

"This is, in a very real sense, the capstone of the initial reconnaissance of the planets that the United States has led for the world since the 1960s," said Alan Stern, New Horizons principal investigator at the Southwest Research Institute in Boulder, Colo.

"We're going farther to reach our target and we're travelling faster than any spacecraft ever has. This is a little bit about leadership, a little bit about re-writing the textbooks about the outer planets. But I also want to point out it's also about inspiring the next generation of scientists and explorers, who we hope will take us to even greater heights."

Equipped with powerful cameras to map the sunlit side of the planet, spectrometers to characterize its space environment, the planet's tenuous atmosphere and surface composition and a student-built dust collector, New Horizons will race past Pluto in July 2015, streaking within 5,500 miles of the surface at a velocity of more than 31,000 mph.

After rapid-fire observations of Pluto, Charon and at least two other recently discovered moons, New Horizons will sail on into the Kuiper Belt, a vast realm of icy dwarf worlds that serves as a reservoir of short-period comets and home to at least one, and presumably more, planets larger than Pluto, the zone's most famous member.

If all goes well, New Horizons, built by the Applied Physics Laboratory at Johns Hopkins University, will fly past at least one other Kuiper Belt world before the mission's funding runs out. After that, the spacecraft will continue on into interstellar space, joining NASA's twin Voyagers and Pioneers as the fifth human artifact to depart the solar system.

"New Horizons is the first mission to the last planet," said project scientist Hal Weaver. "It's going to perform a detailed reconnaissance of Pluto and its companion, Charon. We're actually not going to stop there. We're going to continue to fly past Pluto deep into the Kuiper Belt. New Horizons is going to be going where no other mission has ever been, so it truly is a mission of exploration and discovery.

"Why are we doing this? Science is the driver. Science is the reason new Horizons is making this journey to the outskirts of the solar system. We think the study of Pluto, Charon and the Kuiper Belt objects are key to understanding the origin and evolution of the solar system."

It is remarkable to remember that astronomer Clyde Tombaugh discovered Pluto in 1930 and that in a single generation - 76 years - technology has progressed from propeller-driven aircraft and steamships to spacecraft capable of reaching that distant world.

"Pluto was discovered in 1930," Weaver said. "In 1978, its moon, Charon, was discovered. It has only been in the past 10 years that we've known about this third zone, a torus-shaped region surrounding the sun that we now call the Kuiper Belt. It's only been in really the last 10 years that we've recognized that Pluto and Charon actually are more similar to these small icy worlds in the Kuiper Belt than they are to the other planets.

"All of those objects - Pluto, Charon and the Kuiper Belt objects - have been kept in a deep freeze on the outskirts of the solar system since the time of its formation 4.6 billion years ago," Weaver said. "And for that reason, it's preserved that original material from which the solar system formed and that's one of the important reasons for going there. It's really the frontier of planetary science, it's a region we have never been before."

With the discovery of other sizeable bodies in the Kuiper Belt, including one even bigger than Pluto, the ninth planet's status has been called into question in recent years. Singer Christine Lavin even wrote a song about the debate called "Planet X."


"St. Christopher is looking down on all this
and he says, 'Pluto, I can relate.
When I was demoted from sainthood
I gotta tell you little buddy,
it didn't feel real great'
and Scorpios look up in dismay
because Pluto rules their sign.
Is now reading their daily Horoscope
just a futile waste of time?"

But to Stern, frozen Pluto will always be a planet.
"We've really gone through a revolution, a paradigm shift in planetary science," he said. "We really just didn't realize the diversity of planetary types in our solar system. Pluto looked like a misfit because it was the only one we saw. And just as a Chihuahua is still a dog, these ice dwarfs are still planetary bodies. They're large enough to make themselves round by self gravity and they surely pass the test of planethood.

"So it's really quite an opportunity to first, find that you're notions were wrong, it's almost like a Copernican revolution. The misfit becomes the average. ... The opportunity is to go now and have a chance to study this most common type of planetary body in the solar system for the first time."

But the mission is not without risk.

Because the sun is little more than a bright star when seen from Pluto's distance - a quarter beyond the far end zone in the Rose Bowl - a solar power system would require arrays on the order of 1,200 square yards in size to collect enough light, to generate enough electricity, to power the craft's systems and instruments.

Instead, New Horizons relies on a single radioisotope thermoelectric generator, or RTG, which converts the heat produced by the radioactive decay of plutonium 238 dioxide into electricity. At launch, the RTG will produce about 240 watts of power. By the time the craft reaches Pluto, the power output will have dropped to about 200 watts, enough to drive two household light bulbs. But that's enough to keep New Horizons alive and well.

RTGs have no moving parts and are extremely reliable. The compact generators have powered all of NASA's deep space missions, including the Pioneers and Voyagers, the Ulysses sun-study probe, the Galileo Jupiter orbiter and the Cassini spacecraft currently in orbit around Saturn. RTGs also were used on six Apollo moon missions and the two Viking Mars landers.

In all, 25 RTG-powered missions have been launched by the United States. Three of those missions failed. In one case, the RTG burned up in the atmosphere as designed at that time. In another, the RTG was later recovered. And an RTG aboard the ill-fated Apollo 13 lunar lander now rests at the bottom of the Tonga Trench in the Pacific Ocean.

New Horizons is equipped with a single RTG loaded with about 24 pounds of highly toxic plutonium dioxide. RTGs are designed to withstand the sort of forces one could expect during a launch mishap, but NASA's environmental impact statement concludes there is a 1-in-350 chance of a launch mishap in which plutonium could be released into the environment.

Even so, NASA claims no additional cancer deaths could be expected over the next 50 years as a result of any failure that has a reasonable probability of occurring. In some extremely unlikely cases - the rocket's self-destruct system fails after a major malfunction, for example - the agency concludes there is a more significant biological risk. But the odds of a release after such multiple failures, NASA engineers believe, are in the realm of 1-in-1 million or lower.

Kurt Lindstrom, a senior manager at NASA headquarters in Washington, said major U.S. rockets have a 93.8 percent overall success rate. Of the failures, 5.8 percent would not involve the kind of forces necessary to damage an RTG enough to release plutonium into the environment. Of the 0.4 percent of the remaining mishaps, Lindstrom said less than half would result in 0.1 latent cancer deaths. A "latent cancer fatality" in this case is the statistical probability of developing cancer over 50 years.

"So there's a very low probability of having an accident generally or particularly having an accident that has a radiological release for this mission," he said.

But anti-nuclear activists argue the risks, however small, outweigh the scientific payoff. At a small demonstration Jan. 7 just outside the Cape Canaveral Air Force Station, about three dozen activists, several with children, urged area residents to protest New Horizons' launch.

"We distrust their reasons for needing to launch plutonium," said Maria Telesca-Whipple of the Global Network Against Weapons and Nuclear Power in Space.

"Their impact statement says a 1-in-300 chance of an accident. I've lived here 22 years and have seen accidents with launches that had no plutonium but which released toxic fumes over Cape Canaveral and Cocoa Beach where the school children were told to stay inside. ... We think it's all smoke and mirrors and we think that it has a lot more to do with the military applications (of nuclear power in space). ... We really just doubt that the general population is being told the truth about why we're actually doing this."

The activists also challenge the NASA-Department of Energy environmental analysis and argue alternative technologies might permit a Pluto mission without the need for RTGs.

NASA managers say that isn't true and the White House has officially approved the New Horizons launch. There are no other known political or legal obstacles to the flight. The environmental impact statement is available online.

Even with a powerful Atlas 5 rocket, launching New Horizons directly to Pluto would take some 14 years. Instead, NASA plans to shave five years off the trip by launching New Horizons on a trajectory that will carry it past Jupiter in early 2007. Streaking 1.4 million miles from the planet's cloud tops at 47,000 mph, New Horizons will gain a gravitational boost amounting to an additional 9,000 mph. That's what gets the probe to Pluto by July 14, 2015.

But to take advantage of Jupiter, NASA must launch New Horizons by Feb. 6. While the 2006 launch window extends to Feb. 14, a launch in the last week of the window would result in a Pluto flyby in 2020. Jupiter is not an option at all if the flight slips to 2007.

Pluto currently is on the outbound leg of its elliptical orbit, moving away from the sun. With every year that passes, 77,000 square miles of Pluto's surface disappears into shadow, lost to view from a passing spacecraft. Equally pressing, astronomers believe Pluto's atmosphere will literally freeze out and fall to the surface in the coming years as the planet recedes from the warmth of the sun.

"Some of those atmospheric species are actually going to freeze up just like when you put water in a ice tray and put it in a freezer," Weaver said. "The little layer of water vapor above it, all that freezes out into ice cubes. Well, the same thing is probably going to happen to Pluto. We don't know exactly when it's going to happen, sometime probably within the next few decades."

In short, the science community feels a fair amount of pressure to get New Horizons off the ground before Feb. 6.

NASA originally hoped to launch the mission Jan. 11, but the flight was put on hold for a last-minute investigation to resolve lingering questions about a fuel tank problem that cropped up last year.

Because the New Horizons rocket is the first Atlas 5 to be equipped with five solid-fuel boosters, an RP-1 first stage fuel tank - the part of the rocket solid-fuel boosters attach to - was deliberately over pressurized to demonstrate its ability to handle excessive "loads." The test tank cracked at about 90 psi, twice the normal flight pressure, and an investigation was ordered.

Flight tanks, including the one in the New Horizons rocket, were boroscoped and found to be in good condition. NASA ordered a second inspection to make sure and a Lockheed Martin official said "the Atlas team is absolutely ready to go." NASA agreed the Atlas 5 had a positive margin of safety, but details of a flight readiness review Thursday are not yet known, including how many engineers might have dissented.

If all goes well, the huge rocket's Russian-built RD-180 first stage engine and five solid-fuel boosters will roar to life at 1:24 p.m. Tuesday, the opening of a one-hour 59-minute launch window. While a typical Atlas 5 climbs above its launch gantry in 12 seconds or so, the New Horizons rocket, with its lightweight payload, will take just six seconds as it thunders skyward and then arcs out over the Atlantic Ocean.

Using a hydrogen-powered Centaur second stage, the Atlas will put New Horizons in an elliptical "parking orbit" with an apogee, or high point, of 191 miles and a perigee, or low point, of 102 miles. Twenty-two minutes later, the Centaur will reignite, boosting New Horizons into an orbit around the sun carrying it as far as the asteroid belt between Mars and Jupiter.

For the final kick needed to send the craft to Jupiter, a solid-fuel Boeing Star 48 rocket motor will ignite about 43 minutes after liftoff and burn for about a minute and a half. New Horizons will separate from the spent booster a few minutes later, on its own for the remainder of the long voyage to Pluto.

"The launch carries us out over the Atlantic. By the time we are over the Indian Ocean, we've acquired enough velocity to send us on our way to Pluto," said Project Manager Glen Fountain. "Leaving Earth, the New Horizons will be traveling at eight miles per second. Eight hours later, the spacecraft will pass the orbit of the moon. Remember that the Apollo astronauts took some three days to cover that distance."

Here are launch milestones at a glance (in minutes and seconds after launch):


Guidance to inertial: T-00:08.0

RD-180 main engine ignition: T-00:02.7

Engine operation and thrust at flight level: 00:00.0

Liftoff: 00:01.1

Booster jettison (1,2): 01:46.7

Booster jettison (3,4,5): 01:48.2

Nose cone fairing jettison: 03:23.4

First stage main engine cutoff: 04:27.6

First stage/Centaur second stage separation 04:33.6

Centaur first main engine start (MES1): 04:43.6

Centaur first main engine cutoff (MECO1): 10:06.2

Centaur second main engine start (MES2): 32:22.6

Centaur second main engine cutoff (MECO2): 42:02.2

Centaur/third-stage separation: 42:15.2

Third stage Star48B engine start: 42:52.2

Star48B engine burnout: 44:20.1

Spacecraft separation 47:47.2

Mission managers are not just taking advantage of Jupiter for a gravity assist flyby. They're going to use the planet for an end-to-end test of the spacecraft's instruments, using the encounter as a dress rehearsal for Pluto.
"We will be the eighth mission to Jupiter," Stern said. "One of the dirty little secrets of New Horizons is we'll be returning more bits (of data) from Jupiter than from Pluto because we have much greater bandwidth. ... We have a wide variety of experiments planned to test out our instruments, but also to fill in the gaps and to answer some of the questions the Galileo mission left us with."

NASA's hugely successful Galileo orbiter mapped and studied Jupiter's major moons, its radiation environment and its cloudy atmosphere in unprecedented detail. But an antenna malfunction limited the amount of data it could beam back to Earth, forcing scientists to forego some planned observations of the atmosphere that required enough pictures to make movies. New Horizon will fill in many of those blanks.

In addition, the spacecraft's trajectory will carry it down Jupiter's magnetotail as it flies away into deep space, giving scientists an unprecedented chance to study the teardrop-shaped region of space around Jupiter that is shaped and defined by the planet's powerful magnetic field.

"Our route of flight from Jupiter to Pluto takes us directly down Jupiter's magnetotail out to a thousand jovian radii," Stern said. "This is just a spectacular opportunity for magnetospheric science, nothing like this has ever been flown at any planet. Even at the Earth, there's never been an equivalent fly through of a magnetotail like this."

New Horizons will photograph Jupiter's aurora, its major satellites and a modest ring discovered by the Voyager spacecraft.

"So it's going to be a busy time," Stern said.

But once past Jupiter, NASA plans to put New Horizons into electronic hibernation, fully waking up just once a year for detailed health checks. It will cross the gulf between Jupiter and Pluto spinning at 5 rpm with its high-gain antenna constantly pointed toward Earth.

"The spacecraft will be put to sleep into a hibernation mode with very few subsystems active after we complete the Jupiter gravity assist," said David Kusnierkiewicz, mission systems engineer at Johns Hopkins. "This will conserve some of the useful operating lifetime of the electronics."

New Horizons will, however, broadcast simple diagnostic "beacon" tones that will be listened to once a week by NASA's Deep Space Network of tracking antennas. A coded "green" tone will indicate the spacecraft is healthy. One of seven coded "red" tones will be beamed back if a problem is detected.

"This will be the first operation we've used such a beacon mode, to broadcast the status of the spacecraft and its health back to Earth," Kusnierkiewicz said. "We will listen to this beacon about once a week during the period from Jupiter to Pluto in order to make sure the spacecraft is healthy ... and we'll respond accordingly."

New Horizons is small compared to the school bus-sized Cassini currently in orbit around Saturn, measuring just 27-by-83-by-108 inches and weighing 1,054 pounds at launch, of which 170 pounds is hydrazine maneuvering fuel. It's roughly triangular and about the size of a piano.

The probe is equipped with a single RTG for electrical power and seven state-of-the-art science instruments, including a radio system that will be used to both communicate with Earth and to collect valuable data about Pluto's tenuous atmosphere. The compact instruments typically operate on less power than a night light - two to 10 watts each. Recalling "The Honeymooners" TV series and Ralph Kramden's frequent outbursts of "to the moon, Alice," two of the instruments are named Ralph and Alice.

Operating more than 30 times farther from the sun than Earth, New Horizons is built like a thermos bottle and insulated to retain the heat generated by its electrical systems. Internal temperatures between 50 and 85 degrees Fahrenheit are expected throughout the mission, but small heaters are available just in case it gets colder than expected.

"The New Horizons payload is the most compact, low-power, high-performance payload yet to fly on a U.S. planetary mission for a first reconnaissance flyby," said William Gibson, New Horizons science payload manager.

The instruments are:

- Alice: A 10-pound ultraviolet imaging spectrometer built by the Southwest Research Institute to study the structure and composition of Pluto's atmosphere. It also will be used to look for signs of a charged ionosphere around Pluto and any traces of an atmosphere around Charon.

- Ralph: A 23-pound telescope/camera system developed by Ball Aerospace Corp., NASA's Goddard Space Flight center and the Southwest Research Institute that includes a multi-spectral visible-light camera with seven black-and-white and color CCD detectors and a single infrared channel for spectroscopic studies. Operating in light 1,000 times dimmer than on Earth, Ralph will photograph the sunlit surfaces of Pluto and Charon, providing stereoscopic views, measuring the temperature and mapping abundances of nitrogen, methane, carbon monoxide and water ice. In black-and-white mode, the camera will be able to discern surface features three-tenths of a mile across (0.9 miles across in color mode and 4.3 miles in infrared mode).

- Radio Science Experiment (REX): This is a 3.5-ounce circuit board incorporated in the spacecraft's radio system that was developed by Johns Hopkins and Stanford University. As the spacecraft flies behind Pluto and Charon, radio waves from Earth will be bent slightly as they pass through atmospheric gases. By characterizing those subtle changes, scientists will be able to gain insights into atmospheric temperature and pressure.

- LORRI (long-range reconnaissance imager): A 19-pound digital camera equipped with an 8.2-inch telescope serving as a telephoto lens that will be used for optical navigation on the way to Pluto. At close approach, LORRI, developed by Johns Hopkins, should be capable of detecting surface features as small as 82 feet across. Ninety days out from Pluto, LORRI's pictures will be 10,000 times sharper than current images taken by the Hubble Space Telescope.

- SWAP (Solar Wind at Pluto): Developed by the Southwest Research Institute, SAP will study how Pluto interacts with the solar wind. Scientists believe Pluto loses about 165 pounds of its atmosphere every second. That material is then ionized by sunlight and carried away on the solar wind.

- PEPSSI (Pluto Energetic Particle Spectrometer Science Investigation): A 3.3-pound spectrometer developed by Johns Hopkins to study material escaping from Pluto's atmosphere as well as the atmosphere itself.

- SDC (Student Dust Counter): The only instrument that will remain on for the duration of the new Horizons Mission, the SDC was developed by students at the University of Colorado at Boulder to measure microscopic dust grains in interplanetary space.

"When we arrive at Pluto, we'll be photographing everything in the system at high resolution," Stern said. "The best we can do now with the Hubble, despite all of its capabilities, is about 400 or 500 kilometers (250 to 310 miles) per pixel. That is like putting a state in a single pixel.
"We're going to change that. We'll map everything that is sunlit in the system at one kilometer resolution. And with our long focal length narrow angle camera, called LORRI, we'll be doing Landsat-class resolution as good as 25-to-50 meters per pixel in selected areas. That accounts for the satellites as well as Pluto itself."

Spin stabilized on the way to Pluto, New Horizons will use small hydrazine thrusters to change its orientation as required for scientific observations based on data provided by redundant gyroscopes, accelerometers and star trackers.

The computational horsepower needed to operate the spacecraft and carry out programmed commands from Earth is provided by a radiation-hardened Mongoose V processor running at 12 megahertz.

Data will be stored on two redundant eight-gigabyte solid-state recorders and later beamed back to Earth. New Horizons is equipped with two low-gain antennas for communications when the spacecraft is near Earth, a 12-inch medium-gain dish antenna and an 83-inch-wide fixed dish antenna for use with a high-speed X-band communications system.

But at Pluto's enormous distance from Earth - so far radio signals will take four hours and 25 minutes for a one-way trip - data transmission will occur at a glacial 700 bits per second. As a result, it will take a full nine months to beam back all of the data collected during the Pluto flyby.

Pluto orbits the sun in an elliptical orbit tilted 17 degrees to the plane of the other planets. The orbit comes as close as 2.8 billion miles to the sun and as far as 4.6 billion miles. Between 1979 and 1999, Pluto was closer to the sun than Neptune. It takes the planet 247 years to complete a single orbit, or plutonian year, and it currently is moving away from the sun.

The ice dwarf is tipped over on its side and has a diameter of about 1,460 miles. Gravity is about 6 percent of Earth's and surface temperatures are as low as 387 degrees below zero Fahrenheit. Astronomers have detected spectroscopic signs of nitrogen, carbon monoxide, methane and ice on the surface. The planet has an extremely thin atmosphere composed of nitrogen with small amounts of methane, carbon monoxide and hydrocarbons.

Pluto and its large moon Charon whirl about each other every 6.4 days. Charon is 12,200 miles from Pluto and both worlds turn in gravitational lockstep, always keeping the same face toward each other. Pluto's two other, much smaller known moons orbit two to three times farther out than Charon.

Little more is known about the Pluto system, not surprising given the planet is 50,000 times fainter than Mars when viewed from Earth.

To carry out its mission, New Horizons must traverse some 3 billion miles and then hit a keyhole in space just 186 miles across, a target point at the far end of the launch trajectory that will allow the spacecraft to pass midway between Pluto and Charon.

Detailed observations will begin about five months before the flyby, collecting data that will help flight planners fine-tune the spacecraft's course. Starting about three months out, at a distance of about 62 million miles, New Horizons will begin mapping Pluto and Charon. A few weeks later, the spacecraft's images will become sharper than those taken by the Hubble Space Telescope. Daily observations will commence one month before the encounter.

By that point, scientists hope to know whether two recently discovered moons - and others that may be discovered between now and then - have contributed to any as-yet-unseen rings of debris around Pluto that could pose a threat to the spacecraft as it zips through the system. Stern said New Horizons should still have half a tank of hydrazine rocket fuel left by then, more than enough to change course if necessary to avoid any threats. "Our plan, however, is to fly about halfway between Pluto and Charon, splitting that difference between them," he said. "But it's contingent upon some work we need to do with the Hubble Space Telescope To ensure we avoid any potential debris field ... associated with the orbits of the small satellites, which might generate rings in the system.

"We would want to make sure we would not fly through rings or ringlets. We want to do deeper searches for additional satellite and we want to pin down their orbits so as we fly through that bullÕs-eye, we fly between satellite orbits with good separation and not at the distances that ring system debris may be present."

While trying to avoid danger, the new moons offer an unexpected scientific opportunity.

"It looks because of the geometry we might actually be able to fly pretty close to both of those satellites, maybe one of them before we encounter Pluto and one after," Weaver said. "My own personal feeling right now is we almost have a family here. We have the mother and the father, Pluto and Charon, and these objects seem to be rotating around Pluto all in the same plane. It looks like the same event that produced Pluto and Charon, which was probably catastrophic collision that caused all heck to break loose, a whole bunch of stuff formed a debris disc and you had Pluto and Charon forming. In addition to that in the little disc of material that was left over probably had enough clumpiness in it and maybe these little moons formed."

But Pluto and Charon are the main reason for launching New Horizons, along with the opportunity to study a second Kuiper Belt object in the years after the main encounter.

"At the time of the Voyager missions in the early 70s, the importance of Pluto and, of course, the Kuiper belt, because it wasn't discovered (yet), wasn't appreciated at all," Stern said. "It wasn't very high on the priority list because we didn't realize how much it had to teach us about the origin of the solar system and some of the kinds of physics, particularly atmospheric physics, that we want to learn about. Today, with our better knowledge of the geography of our solar system, we see how central it is to modern planetary science."

New Horizons' close encounter with Pluto will last a full day, 12 hours before and after. The spacecraft cannot enter orbit around the planet because no current rocket can launch a probe carrying enough fuel to arrest the velocity needed to get it there in a reasonable amount of time.

Approaching from the planet's southern hemisphere, the spacecraft will pass within about 5,500 miles of Pluto's surface at 31,300 mph, streaking well inside the orbit of Charon. Fourteen minutes later, the probe will fly past Charon at a distance of 16,800 miles. Fifty-one minutes after Pluto closest approach, New Horizons will disappear behind the planet as viewed from Earth. Two hours and 15 minutes past Pluto closest approach, the spacecraft will pass behind Charon as viewed from Earth, giving the radio science team a chance to look for signs of an atmosphere.

At Pluto's distance from Earth, it will take several hours to transmit a single image back to Earth. High-priority observations will be sent back right away, but it will take nine months to transmit the complete data set.

Weaver said the Pluto-Charon system is unique in the known solar system.

"If you think about this mission in the context of comparative planetology, we have the terrestrial planet region in the inner solar system comprised of Mercury, Venus, Earth and Mars," he said. "Pluto and Charon and the Kuiper Belt objects are nothing like those rocky objects. Then you have the gas giants, the ones that are dominated by thick atmospheres of molecular hydrogen and helium - Jupiter, Saturn, Uranus and Neptune. And then we have the final new frontier in the solar system, the realm of the icy dwarfs and that's what Pluto, Charon and the KB objects belong to. And that has not yet been explored.

"Another interesting thing about Pluto and Charon is they're the only example in the solar system of a binary planet," Weaver continued. "They're more like brothers or sisters than a planet and a moon. They're sort of at one end of the spectrum. Most of the planet-moon systems have much bigger discrepancies between the mass and the size of the planet and its moon and Pluto and Charon are at the other end of the spectrum. By understanding how all of these things formed, that's going to tell us something about planetary dynamics and the inner solar system from the time of its formation.

"Another interesting aspect of Pluto is that it does have an atmosphere and in fact, that's one of the reasons why it's being called a planet. But PlutoÕs atmosphere is weird. It's sort of a transitional case between a traditional planetary atmosphere and a cometary atmosphere, which is not connected to the object at all, it just flies off into space. It's in between. Pluto does have a bound atmosphere but it also has some escaping gases. In fact, it's the only current planet in the solar system whose atmosphere is in the process right now of hydrodynamic escape.

"And not only does the gas escape, as Pluto moves father away from the sun and gets colder and colder, what eventually will happen is the atmosphere will freeze out onto the surface," Weaver said. "We want to get to Pluto with New Horizons before that atmosphere freezes out so we can learn something about Pluto's atmosphere, which in turn will tell us something more generally about the formation and evolution of planetary atmospheres."

Before New Horizons gets to Pluto, astronomers plan to select a second Kuiper Belt object for close-up observations. Plenty of fuel is expected to be available for any necessary course change and the RTG power source should provide enough electricity to operate the instrument package for a full 10 years beyond the Pluto flyby.

"Pluto, of course, is embedded in the Kuiper Belt, the largest structure in our planetary system, dotted with almost a half million worlds and worldlets that are four billion years old," Stern said. "In a real sense, this is not just a journey four billion miles away but also four billion years back in time. It's really no wonder, because of the value of this ancient structure to our understanding of the origin of the solar system, that the National Academy (of Sciences) ranked this mission number one on the runway for a new start in this decade among medium-sized planetary missions like New Horizons."

But Pluto is the star of the show.

"It's a very unusual pair of worlds, the first binary planet system we've ever explored and the first ice dwarf, a whole new class of planets," Stern said. "Whereas we know of four terrestrial planets and four gas giants, we expect there are hundreds, if not thousands, of these ice dwarfs. So this class of planets, which we have not yet reconnoitered, is in reality the most populous class of planetary body in our solar system. That's what this mission is about.

"Some of the other attributes of the Pluto system that make it interesting is it's a scientific wonderland for atmospheric scientists. Its atmosphere is escaping like a comet, but on a planetary scale. It's surface, which is only 40 degrees above absolute zero, is covered in exotic ices, it has strong seasonal and global change effects that we already know are taking place."

"You can see why we think it's going to be like kids in a candy shop when we arrive in a system like this," Stern said. "It just keeps getting better."

[GioFX]

New Horizons science goals

FROM MISSION PRESS KIT
Posted: January 8, 2006

Based largely on what the scientific community wanted to learn about Pluto and Charon, NASA prioritized its science goals for Pluto-system exploration in three categories:

Required

- Characterize the global geology and morphology of Pluto and Charon
- Map surface composition of Pluto and Charon
- Characterize the neutral atmosphere of Pluto and its escape rate

Important

- Characterize the time variability of Pluto's surface and atmosphere
- Image Pluto and Charon in stereo
- Map the terminators (day/night lines) of Pluto and Charon in high resolution
- Map the composition of selected areas of Pluto and Charon at high resolution
- Characterize Pluto's ionosphere and solar wind interaction
- Search for neutral species (including hydrocarbons and nitriles) in Pluto's upper atmosphere
- Search for an atmosphere around Charon
- Determine bolometric bond albedos for Pluto and Charon
- Map the surface temperatures on Pluto and Charon

Desired

- Characterize the energetic particle environment of Pluto and Charon
- Refine bulk parameters (radii, masses, densities) and orbits of Pluto and Charon
- Search for magnetic fields of Pluto and Charon
- Search for additional satellites and rings

NASA defines mission success as meeting the "required" objectives. With its full science payload -- three optical instruments, two plasma instruments, a radio science receiver/radiometer and a dust sensor - New Horizons expects to exceed these requirements, meeting or addressing all of the objectives in each category.

[GioFX]

MONDAY, JANUARY 16, 2006
2125 GMT (4:25 p.m. EST)

The initial portion of Atlas 5 rocket fueling operations is nearing completion for tomorrow's launch of the New Horizons spacecraft. Lockheed Martin technicians are close to finishing the pumping of about 25,000 gallons of kerosene fuel into the rocket's first stage. That propellant will be consumed with liquid oxygen to power the vehicle's Russian-designed RD-180 main engine during the first four-and-a-half minutes of launch.

The first stage liquid oxygen supply, along with the super-cold liquid oxygen and liquid hydrogen for the Centaur upper stage, will be loaded into the rocket during the final two hours of tomorrow's countdown.

The launch team will be wrapping up today's planned activities and securing the rocket for the evening. Countdown work resumes before dawn tomorrow when the Atlas 5 is powered up at about 5:24 a.m. EST. Routine pre-flight tests of vehicle systems and preparations for cryogenic fueling are among the chores during the morning.

At 10:44 a.m., the count will enter a planned 30-minute built-in hold at the T-minus 120 minute mark. This pause gives the launch team the opportunity to catch up on any work running behind the timeline or deal with technical glitches. A poll of team members occurs five minutes before the end of the hold to verify everyone is ready for liquid oxygen and liquid hydrogen fueling.

Chilling of propellant lines and tanks is performed to thermally condition the equipment in preparation for flowing the super-cold fuels. Centaur liquid oxygen loading should begin at about 11:31 a.m., followed by Atlas first stage liquid oxygen and finally Centaur hydrogen fueling.

A final hold is planned at T-minus 4 minutes. This will be a 10-minute hold starting at 1:10 p.m. EST to conduct readiness polls of senior management, the launch team members, Range and weather. If all elements are deemed "go" for launch, the clock will resume ticking at 1:20 p.m.

The launch window extends from 1:24 to 3:23 p.m. EST.

[GioFX]

Atlas 5 rollout:







The Lockheed Martin Atlas 5 rocket was rolled from the Vertical Integration Facility to the Complex 41 launch this morning.

[Octane]

Ancora poche ora al lancio.. anche se dovremo aspettare appunto questi 8-9 anni per vedere i risultati di tutti gli sforzi del team

[Octane]

The computational horsepower needed to operate the spacecraft and carry out programmed commands from Earth is provided by a radiation-hardened Mongoose V processor running at 12 megahertz.

Interessante capire con che classi di microprocessori viaggiano i veicoli spaziali..

http://www.cpushack.net/space-craft-cpu.html
http://klabs.org/DEI/Processor/Mongoose/

This paper describes high reliability radiation hardened computers built by Sandia for application aboard Department Of Energy (DOE) Satellite programs requiring 32-bit processing. The computers highlight a radiation hardened (1 Mrad(Si)) R3000 executing up to 10 Million Reduced Instruction Set Instructions (RISC) Per Second (MIPS), a dual purpose module control bus used for real-time fault and power management which allows for extended mission operation on as little as 1.2 watts, and a Local Area Network capable of 480 Megabits per second. The Central Processing Unit (CPU) is the NASA Goddard R3000 nicknamed the "Mongoose or Mongoose 1". The Sandia Satellite Computer (SSC) uses Rational’s Ada compiler, debugger, operating system kernel, and Enhanced Floating Point Emulation Library targeted at the Mongoose.

http://www.synova.com/proc/mg5.html

[Frank1962]

sulla ISS un 386 !? ...ma si vogliono male alla nasa/esa? ......io ci avrei messo un MIPS R10000

[Octane]

Originariamente inviato da Frank1962

sulla ISS un 386 !? ...ma si vogliono male alla nasa/esa? ......io ci avrei messo un MIPS R10000

cmq il Mongoose V e' ancora piu' semplicee' infatti basato sul core di un R3000

[Frank1962]

Originariamente inviato da Octane

cmq il Mongoose V e' ancora piu' semplicee' infatti basato sul core di un R3000

alla fine se un processore vuole definirsi RISC non può avere una isa complessa più di tanto .....e poi cmq MIPS è sempre MIPS!!!

[GioFX]

1614 GMT (11:14 a.m. EST)

T-minus 120 minutes and counting! Today's countdown is marching forward for launch of the Atlas 5 rocket and New Horizons headed for Pluto. Clocks have one more built-in hold planned at T-minus 4 minutes. That pause will last 10 minutes, giving the launch team one last chance to catch up on work running late or deal with any problems.

[GioFX]

1614 GMT (11:14 a.m. EST)

Chilldown thermal conditioning of the mobile launch platform upon which the rocket stands is beginning. This is meant to ease the shock on equipment when supercold cryogenic propellants start flowing into the rocket a short time from now.

1621 GMT (11:21 a.m. EST)

The Centaur liquid oxygen pad storage area has been prepped. The next step is conditioning the transfer lines, which is now beginning to prepare the plumbing for flowing the cryogenic oxidizer.

[GioFX]

1624 GMT (11:24 a.m. EST)

Liftoff is now two hours away. Pressure checks of the Atlas 5 rocket's first stage fuel tank have been completed. That tank was loaded with about 25,000 gallons of kerosene propellant yesterday afternoon.

[GioFX]

1628 GMT (11:28 a.m. EST)

Following the thermal conditioning of the transfer pipes, filling of the Centaur upper stage with 4,300 gallons of liquid oxygen has begun at Cape Canaveral's Complex 41.

The liquid oxygen -- chilled to Minus-298 degrees F -- will be consumed during the launch by the Centaur's single RL10 engine along with liquid hydrogen to be pumped into the stage a little later in the countdown. The high-energy Centaur will perform two firings today to propel the New Horizons spacecraft out of Earth orbit.


1634 GMT (11:34 a.m. EST)

The Centaur liquid oxygen tank is now 10 percent full.


1641 GMT (11:41 a.m. EST)

About 40 percent of the Centaur liquid oxygen tank has been filled so far.

[GioFX]

1812 GMT (1:12 p.m. EST)

Engineers have determined the first stage liquid oxygen fill and drain valve issue is not a constraint. The issue is understood.


1813 GMT (1:13 p.m. EST)

NEW LAUNCH TIME! Liftoff has been delayed to 1:45 p.m. EST due to gusty ground winds. Also, the valve issue needs to be wrapped up.

[GioFX]

1838 GMT (1:38 p.m. EST)

NEW LAUNCH TIME! Liftoff has been postponed again. The new target is 2:10 p.m. EST. The further delay allows the team to assess the high-altitude winds and generate a flight profile based on those conditions.


1842 GMT (1:42 p.m. EST)

A new flight profile load is being created from the upper level wind speed and direction information gathered by weather balloons sent up from the Cape through the countdown.

[duchetto]

cos'è quel fumo che fuoriesce dal vettore?

[IcEMaN666]

sto seguendo su nasa live...c'è un vento della madonna secondo me non parte...gli alberi si muovono come fruscelli

[IcEMaN666]

Originariamente inviato da duchetto

cos'è quel fumo che fuoriesce dal vettore?

l'umidità dell'aria a contatto con il propellente liquido (ossigeno e idrogeno) dovrebbe essere

[GioFX]

Originariamente inviato da duchetto

cos'è quel fumo che fuoriesce dal vettore?

è lo sfiato dalla valvola della condotta dell'ossigeno.