On 7^th February 1999, a Delta II rocket was launched from from Cape Canaveral Air Station, Florida. On board was Stardust. Stardust was a NASA probe designed to make three orbits of the sun. During that time it would collect samples of interstellar dust. This dut, it is thought, pre-dates the formation of the sun and should help scientists understand the evolution of the solar system.


The launch of Stardust.
Photo Credits: NASA/JPL

On 2^nd January 2004 Stardust carried out it's primary mission, passing within 500Km of Comet Wild 2 (named after its Swiss discoverer and pronounced "Vilt 2"). Here it collected samples of dust from the comet itself.


The nucleus of Comet Wild 2 as observed by Stardust.
Photo Credits: NASA/JPL


A capsule containing the samples was returned to Earth on 15^th January 2006. The samples are now being analysed.


The Stardust capsule during
re-entry.
Photo Credits: NASA/JPL


Results of the analysis are now being released and some of those results and findingd are reproduced in this thread.

NASA Spacecraft's Pinch of Comet Dust Reveals 'Cosmic Zoo'

12.14.06

Comet dust Materials formed in different times and places in space mixed "a whole lot" during the solar system's formation, according to an international team of scientists who studied comet particles captured by NASA's Stardust spacecraft in January 2004.

About 170 scientists studied bits of material caught by the Stardust spacecraft during its encounter with comet Wild 2. The scientists' findings appear in seven reports about the mission in the Dec. 15, 2006, issue of the journal Science. Stardust delivered the first pristine, solid samples from outside the Earth-moon system when a capsule containing the comet materials parachuted into Utah in January 2006.


Image Above: Artist's concept of Stardust studying a comet's
environment, made of dust and ice.

"Comet dust seems to be a real zoo of things; we see all kinds of particles that are clearly formed at different places, possibly at different times and certainly under different conditions," said Scott Sandford, lead author of the 'organics' paper and a scientist from NASA Ames Research Center in California's Silicon Valley. His paper also revealed that scientists found a new class of organics in the comet dust.

A panel of three Stardust scientists will present additional findings during a news conference Thursday, Dec. 14, at 5 p.m. EST (2 p.m. PST) at the American Geophysical Union fall meeting in San Francisco in the Moscone Center South, Room 232 (747 Howard Street, between 3rd and 4th Streets). The panelists include Stardust principal investigator Donald Brownlee, a professor at the University of Washington, Seattle, and lead author of an overview technical paper; Sandford; and Mike Zolensky of NASA Johnson Space Center, Houston, who is lead author of a study about the mineralogy of the captured comet particles.

"All seven papers, to some degree, indicate that when the solar system was forming, there was a whole lot of mixing going on," Sandford said.

Brownlee estimates that as much as 10 percent of the material in comets came from the inner solar system. "That's a real surprise because the common expectation was that comets would be made of interstellar dust and ice," Brownlee observed.

The Stardust spacecraft was launched on Feb. 7, 1999, from Cape Canaveral Air Station, Fla., aboard a Delta II rocket. The NASA probe flew through comet dust and captured specks of it in a very light, low-density substance called aerogel. The capsule – small enough to hug – landed in the Utah Test and Training Range, southwest of Salt Lake City, on Jan. 15, 2006. During the capsule's high-speed reentry into Earth's atmosphere, NASA studied the capsule's heat shield material, which yielded information that could be useful for heat shield development for future missions to the moon and beyond.

After the preliminary examinations were complete, all the samples were transferred to NASA's curatorial office at NASA Johnson, where they will be made available to the general scientific community for more detailed study.

"I anticipate that people will be asking for and working on these samples for decades to come," Sandford said.

For more information about Stardust studies and other mission information, visit:

http://www.nasa.gov/centers/ames/research/2006/stardust_feature.html

John Bluck
NASA Ames Research Center, Moffett Field, Calif.
Phone: 650-604-5026
Email: jbluck@mail.arc.nasa.gov

Source: NASA - Missions - Stardust

Stardust Findings Suggest Comets More Complex than Thought

12.14.06

Comets may be more than just simple conglomerations of ice, dust and gases.

Some may be important windows on the early solar system. Others may have contributed materials necessary to the development of life on our own planet.

Scientists have found a wide range of compositions and structures for the comet Wild 2 particles that were captured and returned to Earth by the Stardust mission. Their findings indicate the formation of at least some comets may have included materials ejected from the inner solar system to the far and cold outer edge of the solar nebula.


Red/green stereo anaglyph of comet Wild 2.

"Comet dust seems to be a real zoo of things; we see all kinds of particles that are clearly formed at different places, possibly at different times and certainly under different conditions," said Scott Sandford, lead author of the 'organics' paper and a scientist from NASA Ames Research Center in California's Silicon Valley. His paper also revealed that scientists found a new class of organics in the comet dust.

A panel of three Stardust scientists will present additional findings during a news conference Thursday, Dec. 14, at 5 p.m. EST (2 p.m. PST) at the American Geophysical Union fall meeting in San Francisco in the Moscone Center South, Room 232 (747 Howard Street, between 3rd and 4th Streets). The panelists include Stardust principal investigator Donald Brownlee, a professor at the University of Washington, Seattle, and lead author of an overview technical paper; Sandford; and Mike Zolensky of NASA Johnson Space Center, Houston, who is lead author of a study about the mineralogy of the captured comet particles.

"All seven papers, to some degree, indicate that when the solar system was forming, there was a whole lot of mixing going on," Sandford said.

Brownlee estimates that as much as 10 percent of the material in comets came from the inner solar system. "That's a real surprise because the common expectation was that comets would be made of interstellar dust and ice," Brownlee observed.

The Stardust spacecraft was launched on Feb. 7, 1999, from Cape Canaveral Air Station, Fla., aboard a Delta II rocket. The NASA probe flew through comet dust and captured specks of it in a very light, low-density substance called aerogel. The capsule – small enough to hug – landed in the Utah Test and Training Range, southwest of Salt Lake City, on Jan. 15, 2006. During the capsule's high-speed reentry into Earth's atmosphere, NASA studied the capsule's heat shield material, which yielded information that could be useful for heat shield development for future missions to the moon and beyond.

After the preliminary examinations were complete, all the samples were transferred to NASA's curatorial office at NASA Johnson, where they will be made available to the general scientific community for more detailed study.

"I anticipate that people will be asking for and working on these samples for decades to come," Sandford said.

For more information about Stardust studies and other mission information, visit:

http://www.nasa.gov/centers/ames/research/2006/stardust_feature.html

Bill Jeffs
NASA Johnson Space Center, Houston

Source: NASA - Missions - Stardust

Astrobiology and Stardust

12.14.06

Comets may be more than just simple conglomerations of ice, dust and gases.

Carl Sagan once said “We are all star stuff.” But how? What does that really mean? One of the fundamental questions of astrobiology, how does life originate and evolve?, provides a structure in which to examine the relationship between life and the cosmos. Everywhere life has been found on Earth, which is essentially every place in which it has been sought, life’s intimate connection with water has also been found. Within the framework of contemplating life’s cosmic origins, one must also ask about the history of water on Earth. NASA’s Stardust mission has provided the opportunity for astrobiologists to gain deeper insight into this history.


Stardust Returns to Earth.

Many scientists from the NASA Astrobiology Institute (NAI) have been involved in the Stardust mission, spearheaded by none other than Stardust PI Don Brownlee at the University of Washington. The list also includes Scott Sanford of the NAI NASA Ames Team, lead author of one of the papers in this week’s Science, and George Cody of the NAI Carnegie Institution of Washington Team.

“Comets are important to the understanding of the origin of life,” said Brownlee, “we have always considered Stardust an astrobiology mission.” Results from analysis of the Stardust samples have brought new insight to bear on the relationship between the inner and outer solar system. “The samples we’ve obtained from Stardust have helped us understand both the origin of water and other volatiles, as well as their delivery mechanisms to the early Earth,” said Brownlee.

The NAI has supported the groundwork needed for the complex analytical work demanded by the project. Brownlee’s graduate student, Graciella Matrajt, who is funded by NAI, was able to prepare and image organic materials from the returned samples; a complex process considering the danger of overprinting the organics already resident on the equipment. Brownlee points out that this type of support “…has been critical in pushing the boundaries of our analytical capabilities.”

Brownlee notes, “The success of Stardust demonstrates the power of having samples in hand,” and urges the community to take the need for sample return missions more seriously. Part of NAI’s mission is to provide scientific and technical leadership on astrobiology investigations for current and future space missions. With leadership experience on Cassini-Huygens, MER, Deep Impact, MESSENGER, TPF, Kepler, MRO, MSL, and SIM to name a few, NAI is in a position to continue its pioneering role in helping NASA’s missions produce the best science possible. We have achieved our goal in supporting the success of Stardust.

For more information about Stardust studies and other mission information, visit:

http://www.nasa.gov/centers/ames/research/2006/stardust_feature.html

Daniella Scalice
NASA Astrobiology Institute

Source: NASA - Missions - Stardust

Comets as Toolkits for Jump-starting Life

12.14.06

Comets may be more than just simple conglomerations of ice, dust and gases.

ust as kits of little plastic bricks can be used to make everything from models of the space shuttle to the statue of liberty, comets are looking more and more like one of Nature's toolkits for creating life. These chunks of ice and dust wandering our solar system appear to be filled with organic molecules that are the building blocks of life.

The discovery of two kinds of nitrogen-rich organic molecules in comet Wild 2 using NASA's Stardust spacecraft is the latest addition to the set of bits and pieces useful to the origin of life that's been found in comets.


Image above: NASA Goddard researchers Jason
Dworkin (left) and Daniel Glavin (right) examine
aerogel from the Stardust mission.
Print-resolution copy (1.8 meg jpg image)
Credit: NASA

These discoveries were made by members of the Stardust Preliminary Examination Team, a group of scientists who have been studying the samples returned from comet Wild 2 by the Stardust spacecraft in January 2006.

"These results show that comets could have delivered nitrogen rich organic compounds to the early Earth where they would have been available for the origin of life," said Scott Sandford of NASA's Ames Research Center, Moffett Field, Calif.

"This discovery shows that the menu of compounds available for the origin of life was richer than had been previously thought," said Jason Dworkin of NASA's Goddard Space Flight Center, Greenbelt, Md.

"The two molecules we discovered in comet Wild 2, methylamine and ethylamine, provide a source of fixed nitrogen, a commodity which could have been rare on the ancient Earth. Nitrogen fixation is the conversion of the very stable nitrogen (N2) gas in our atmosphere to a biologically usable form, like an amine or nitrate -- the same compounds found in fertilizer. Enzymes that fix nitrogen appear to be ancient, so finding a source of fixed nitrogen would have been an early challenge for life from the time of its origin. We determined that at least one type of comet would have provided significant quantities of stable, fixed nitrogen in the form of methylamine and ethylamine," added Dworkin.

This is the first time these molecules have been detected in comets. As the Stardust spacecraft sped through the comet's tail at 13,000 miles per hour, a set of aerogel tiles mounted on a boom trapped dust and gas from the comet. Often referred to as "frozen smoke", aerogel is the world’s lowest density solid. Its low density allows it to slow and capture comet dust particles without vaporizing them. Although the mission's goal was to return samples of comet dust to Earth, the researchers looked for organic molecules that were embedded in the aerogel itself, rather than trapped in dust grains. "We found that the aerogel acted like a sponge, absorbing organic gases from the comet nucleus," said Daniel Glavin of NASA Goddard.


Image above: A close-up view of Stardust aerogel.
Print-resolution copy (1.6 meg jpg image)
Credit: NASA

"And just like squeezing a sponge, we squeezed out all the good stuff -- the water-soluble organics -- by boiling samples of the aerogel in ultra-high purity water," added Glavin. The team analyzed the aerogel water extract with a liquid chromatograph mass spectrometer instrument to identify the organic molecules.

Since Earth is crawling with life, the team had to rule out contamination from our planet before it could say the molecules likely came from the comet. Glavin and Dworkin analyzed dozens of "pre-flight" aerogels that were not flown on Stardust in order to understand the organic background levels within the aerogel.

The team found high levels of both methylamine and ethylamine in aerogel that was exposed to comet Wild 2. While they did find small amounts of methylamine and trace levels of ethylamine in the pre-flight aerogel, the total amount in the unflown aerogel was over 100 times less. Also, the relative amounts of the two molecules were very different from that found in the comet-exposed aerogel. The different total and relative amounts convinced the team that most of the two chemicals in the Stardust sample came from the comet. However, since Stardust was in space for seven years, the team had to be sure that the two chemicals weren't simply picked up while the spacecraft was cruising toward Wild 2. Since the pressure in space is so low, the spacecraft can release gas or volatile materials acquired during its manufacture on Earth. This is called "outgassing", and it could have contaminated the aerogel as well.

To reveal the levels of contamination from these two sources, the Stardust team included a special piece of aerogel called the "witness tile" on the spacecraft. It's a piece of aerogel located behind a dust shield that protected the spacecraft from high-speed collisions with comet particles. This location kept the witness tile from being exposed to gas and dust from the comet. But the witness aerogel was exposed to everything else Stardust encountered, including the manufacturing processes, shipping, the launch, spacecraft outgassing, and Earth reentry.

"When we analyzed a sample of the witness tile, we did not detect methylamine or ethylamine, so we don't think Stardust was contaminated with these two chemicals on the way to Wild 2," said Glavin.

For more information about Stardust studies and other mission information, visit:

http://www.nasa.gov/centers/ames/research/2006/stardust_feature.html

Bill Steigerwald
NASA Goddard Space Flight Center

Source: NASA - Missions - Stardust

In July, 2005, the Deep Impact spacecraft released a probe that blasted a crater in comet Tempel 1, spilling its elements into space so scientists could discover its composition. The assault was justified because comets are thought to be leftovers from the formation of our solar system, so learning more about them helps to understand how our solar system came to be.

Since those fireworks, the spacecraft has cruised silently through space, healthy and able to take on another mission, if needed. The Deep Impact team realized that with the spacecraft already built and launched, extra discoveries could be made at very little cost, a bonus for an already successful mission.

The team put together a proposal to use the spacecraft's telescope to observe the atmospheres of alien worlds, and to visit another comet. The proposed extended mission is called EPOXI (Extrasolar Planet Observation and Deep Impact Extended Investigation), and it has received $500,000 from NASA for an initial study to determine the requirements and costs in greater detail.


Image above: An artist's concept of a "Hot
Jupiter" extrasolar planet.
Print-resolution copy
Credit: NASA/JPL-Caltech

If approved, as Deep Impact passes by Earth on December 31, 2007, it will use our planet's gravity to direct itself to comet Boethin. While it cruises toward the comet, the first part of the extended mission -- the investigation of alien worlds --would begin in January, 2008. More than 200 alien (extrasolar) planets have been discovered to date. Most of these are detected indirectly, by the gravitational pull they exert on their parent star. Directly observing extrasolar planets is very difficult, because the star is so brilliant compared to the planet. Planets simply get lost in the glare, like fireflies near a headlight.

However, sometimes by chance the orbit of an extrasolar planet is aligned so that it eclipses its star as seen from Earth. In these rare cases, light from the extrasolar world can be seen directly. "When the planet appears next to its star, your telescope captures their combined light. When the planet passes behind its star, your telescope only sees light from the star. By subtracting light from just the star from the combined light, you are left with light from the planet. We can analyze this light to discover what the atmospheres of these planets are like," said Drake Deming of NASA's Goddard Space Flight Center, Greenbelt, Md., Deputy Principal Investigator for EPOXI.

Image above: This diagram illustrates how astronomers can capture the elusive spectra of hot-Jupiter planets. Spectra are an object's light spread apart into its basic components, or wavelengths. By dissecting light in this way, scientists can sort through it and uncover clues about the composition of the object giving off the light. To capture a spectrum of the planet, the telescope must observe the system twice. It takes a spectrum of the star together with the planet (first panel), then, as the planet disappears from view, a spectrum of just the star (second panel). By subtracting the star's spectrum from the combined spectrum of the star plus the planet, it is able to get the spectrum for just the planet (third panel).
Print-resolution copy
Credit: NASA/JPL-Caltech

Deep Impact will observe three nearby stars with "transiting extrasolar planets," so named because the planet transits, or passes in front of, its star. The planets were discovered earlier and are giant planets with massive atmospheres, like Jupiter in our solar system. They orbit their stars much closer than Earth does the sun, so they are hot and belong to the class of extrasolar planets nicknamed "Hot Jupiters".

These giant planets may not be alone. If there are other worlds around these stars, they might also transit the star and be discovered by the spacecraft. Even if they don't transit, Deep Impact could find them indirectly. Their gravity will pull on the transit planets, altering their orbits and the timing of their transits. "Since Deep Impact will be able to stare at these stars for long periods, we can observe multiple transits and compare the timing to see if there are any hidden worlds," said Deming.

Around May of 2008, the extended mission will transition to the second phase as the spacecraft approaches comet Boethin. In mid-December 2008, Deep Impact will come within 700 kilometers (435 miles) of Boethin. Passing by at more than 10 kilometers per second (6.2 miles per second), Deep Impact will only have about a half-dozen hours to make detailed observations.

"The comet hit by Deep Impact's probe, Tempel 1, was unusual compared to other comets we have seen up close," said Michael A'Hearn of the University of Maryland, College Park, Principal Investigator for EPOXI. For example, it appears that several pieces may have come together to build up the comet's nucleus, the lump of ice and dust that comprises the solid part of a comet. Second, comets vent gases as they come closer to the sun and warm up. Tempel 1 did this as well, but in an unusual way. Water vapor vents appeared all over the nucleus, as expected, but carbon dioxide only vented from certain parts. Also, since comets are a mixture of dust and ice, scientists expected dust to be dragged out from any gas vent, but dust only came from the carbon dioxide vents. Third, there are some very smooth areas on the nucleus, as if something had flowed there. However, the comet's gravity is extremely weak, so scientists don't understand how any material could be pulled down to flow across the surface. Finally, there are circular areas with raised rims that resemble impact craters. However, craters haven't been seen on any other visited comets so far. Scientists are surprised to see them on Tempel 1 because it's hard to understand how craters would last, since the surface gets vaporized every time the comet's orbit takes it close to the sun.

Image above: This spectacular image of comet Tempel 1 was taken 67 seconds after it obliterated Deep Impact's impactor spacecraft. The image was taken by the high-resolution camera on the mission's flyby craft. Scattered light from the collision saturated the camera's detector, creating the bright splash seen here. Linear spokes of light radiate away from the impact site, while reflected sunlight illuminates most of the comet surface. The image reveals topographic features, including ridges, scalloped edges and possibly impact craters formed long ago.
Credit: NASA/JPL-Caltech/UMD

"We want a close look at Boethin to see if the surprises of Tempel 1 are more common than we thought, or if Tempel 1 really is unusual," said A'Hearn.

Deep Impact does not have another probe, so Boethin will not get hit, but the close-up view will allow the spacecraft's infrared spectrometer to make a map of the comet's surface composition, while the telescope observes surface features.

"It's exciting that we were able to combine two totally independent science investigations into a single project. However, both relate to understanding how solar systems form and evolve," said A'Hearn.

According to the team, comets and their asteroid kin are the leftover building blocks of planets, and might have contributed water and organic material to the ancient Earth, aiding the start of life. By observing extrasolar planets, scientists can compare them to our own and discover what we have in common, what we don't, and perhaps why.

"The EPOXI mission is short, sweet, focused, and gives a rich science return," said Deming.

Elements of the EPOXI mission were among approximately two dozen proposals submitted in response to NASA's Discovery Program 2006 Announcement of Opportunity last April. NASA selected three proposed new Discovery-class missions, and three "mission of opportunity" proposals that would make use of existing NASA spacecraft, for concept development funding. Two of the three existing spacecraft proposals used the Deep Impact spacecraft, and were later combined into the EPOXI proposal. NASA may select one or more investigations to continue into a development effort after detailed review of the concept studies. Decisions about which mission concepts will proceed to development are expected in late 2007. If selected, the EPOXI project will be managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Bill Steigerwald
NASA Goddard Space Flight Center

Source: NASA/GSFC - News

The Royal Astronomical Society / National Astronomy Meeting 2007 press release is reproduced below:

UK scientists are preparing to analyse miniscule impact craters collected by NASA's Stardust mission as it flew through interstellar dust streams. These craters contain the residues of the dust particles that are the seeds of our own Solar System.

A UK consortium of researchers from the University of Leicester, Natural History Museum, Kent University, Glasgow University and Open University have been studying the cometary samples which were delivered a few weeks after the samples were returned to Earth. The interstellar dust particles are about ten nanometres across (one hundred thousandth of a millimetre) and they are even smaller than many of the particles that Stardust collected when it flew through the coma of Comet Wild 2.

In a presentation at the Royal Astronomical Society's National Astronomy Meeting in Preston on 18th April, Dr John Bridges from the University of Leicester will describe how techniques developed to analyse material from the comet's tail will be used to study the interstellar particles. A focussed beam of electrically charged particles will be used to extract the residue of the dust from the craters. Once the material is no longer shielded by the crater walls, it can be examined using a transmission electron microscope.

"The interstellar dust particles collected by Stardust are so tiny that they pose huge analytical challenges," said Dr Bridges. "Having spent the time perfecting our techniques and analysing Comet Wild 2, we are very excited by the prospect of these samples. Our analysis of samples from the comet's tail revealed that its composition was more complex than we'd thought and indicated an unexpected mixing of refractory and volatile material in the early Solar System. The interstellar particles will take us one step farther back and allow us to look at the composition of the dust cloud from which the Solar System formed."

The Stardust mission spent 4 months collecting interstellar dust during its 2.88 million mile journey to Comet Wild-2 and back to Earth. The return capsule, containing the dust and samples from the comet's tail, landed in the desert in Utah in January 2006. Since then, samples have been distributed to selected researchers around the world.

FURTHER INFORMATION

The Stardust Mission
Stardust, a project under NASA's Discovery Program of low-cost, highly focused science missions, was built by Lockheed Martin Space Systems, Denver, Colorado, and is managed by the Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. The mission's Principal Investigator is Dr. Donald Brownlee of the University of Washington in Seattle, WA. UK involvement is funded by the Science and Technology Facilities Council.

More information on the Stardust mission is available at http://stardust.jpl.nasa.gov/home/index.html.

NOTES

Royal Astronomical Society's National Astronomy Meeting
The RAS National Astronomy Meeting is the UK's premier meeting for the astronomy, solar system and space science communities. The RAS-NAM 2007 is hosted by the University of Central Lancashire and is joined by the UK Solar Physics and Spring MIST meetings. It is sponsored by the Royal Astronomical Society, the UK Science and Technology Facilities Council and the University of Central Lancashire.

http://www.nam2007.uclan.ac.uk/info.php


IMAGES


Residue-bearing crater from a Stardust Foil
© JPL/Unis. of Leicester, Kent, Glasgow, Open University and Natural History Museum

CONTACT INFORMATION
Dr John Bridges
Space Research Centre
Dept. of Physics & Astronomy
University of Leicester
University Road
Leicester
LE1 7RH
UK
E-mail: j.bridges@le.ac.uk
Tel: +44 (0) 116 252 2007
Fax: +44 (0) 116 252 2464

From 16-18th April, Dr Bridges can be contacted via the NAM press office.

Source: RAS - NAM Press Release

Sept. 26, 2007: The flash! The dazzle! The front page of the New York Times! Two years ago, NASA's Deep Impact spacecraft dropped an 820 lb copper projectile onto Comet Tempel 1, unleashing an explosion that made headlines around the world.

Exploding comets tend to have that effect. But how many people know what happened after the blast? The surprising answer is none--not even NASA.

Deep Impact's prime mission was to punch a hole in Tempel 1 and look inside, giving researchers their first glimpse of a comet's internal structure. But "we were never able to see the crater because the cloud of debris was so thick," says Michael New of NASA Headquarters.


Above: Deep Impact strikes Comet Tempel 1. [More]

Why didn't Deep Impact wait until the dust cleared? It couldn't. The mission was designed from the beginning as a high-speed flyby, giving extra velocity to the "bullet." Orbiting was not an option. Carried by its own momentum, Deep Impact sailed away before the cloud had time to dissipate.

Take 2: NASA is going back for a second look.

"We're sending another spacecraft back to Tempel 1, the Stardust probe," says New.

Stardust is famous for its January 2004 flyby of Comet Wild 2. Severely buffeted by jets of gas and debris flowing from the comet, Stardust nevertheless managed to snatch thousands of samples of comet dust and return them to Earth for analysis. "Stardust is one of the great successes of NASA's Discovery program," says New. (The Discovery program launches innovative, inexpensive spacecraft every 18-to-24 months on cutting edge missions. Deep Impact is also part of this program.)

At first, Stardust was simply retired, sailing the void with nothing to do—but now it is being recycled as "Stardust-NExT," short for New Exploration of Tempel 1. Planetary science professor Joe Veverka of Cornell University is the mission's principal investigator.

"We're very excited to go back," says Veverka. "Stardust is due to reach Comet Tempel 1 in 2011. By then the debris cloud will be long gone and we should get a clear view of the crater."

Peering into the crater, however, "is only half the story," says Veverka. Before the cloud spoiled the view, Deep Impact's cameras recorded some surprising things:



For one, the comet is ringed by a strangely-layered "sedimentary" terrain. There are no rivers on comets, so what causes these features? "Good question," says Veverka. One possibility: comets might be formed in layers. "Imagine two small proto-comets smashing into one another, sticking together and flattening like pieces of playdough," he says. Or maybe the layers are created via some form of hot erosion when the comet swings past the sun every 6.5 years. "We just don't know."

Stardust will gather important clues. "We're returning to the comet almost exactly one orbit--that is, one comet-year--after the first visit. This gives us a chance to see how solar heating might have altered Tempel 1's face."

Another surprise was landslides. "Deep Impact saw an enormous flow of smooth, powdery material" completely covering about a kilometer of underlying terrain, says Veverka. This feature is as mysterious as the layers, but it could explain one thing: why Deep Impact's debris cloud was so troublesome. "We might have hit a patch of deep powder," adds New. "Fine particles tend to make big clouds that are hard to see through."

"This is why we explore," adds Veverka. "Tempel 1 is an amazing comet."


Above: Comet Tempel 1--the view from Stardust in 2011.
[Larger image] [animation]

Veverka notes that recycling a mission like Stardust is cheaper than sending a whole new spacecraft. "Stardust-NExT costs less than 15% of a full-up Discovery mission."

"Giving new assignments to veteran spacecraft represents not only creative thinking and planning, but also a prime example of getting more from the budget we have," agrees Alan Stern, associate administrator of NASA's Science Mission Directorate.

Deep Impact is being recycled, too. "We're using Deep Impact for two new projects," explains New. One is called DIXI (Deep Impact Extended Investigation): "Deep Impact will fly by Comet Boethin in December 2008 for a close-up investigation of the comet's nucleus." The second is EPOCh (Extrasolar Planet Observation and Characterization): "Cameras on Deep Impact will target nearby stars with known giant planets. By watching these planets transit (pass in front of) their stars, Deep Impact will be able to determine whether they possess rings and/or moons." For this work, EPOCh's sensitivity will exceed that of existing ground and space-based observatories, possibly leading to the discovery of new Earth-sized planets.

No crater? No problem. Says New: "You can't keep a good Discovery mission down."



Discovery Program -- home page

Deep Impact -- home page

NASA's Future: The Vision for Space Exploration

Source: Science@NASA

The press release is reproduced below:

Grey Hautaluoma
Headquarters, Washington
202-358-0668
grey.hautaluoma-1@nasa.gov

DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle@jpl.nasa.gov

Nancy Neal
Goddard Space Flight Center, Greenbelt, Md.
301-286-0039
nancy.n.jones@nasa.gov

Lee Tune
University of Maryland, College Park
301-405-4679
ltune@umd.eduv


RELEASE: 07-279

NASA Sends Spacecraft on Mission to Comet Hartley 2

WASHINGTON - NASA has approved the retargeting of the EPOXI mission for a flyby of comet Hartley 2 on Oct. 11, 2010. Hartley 2 was chosen as EPOXI's destination after the initial target, comet Boethin, could not be found. Scientists theorize comet Boethin may have broken up into pieces too small for detection.

The EPOXI mission melds two compelling science investigations -- the Extrasolar Planet Observation and Characterization and the Deep Impact Extended Investigation. Both investigations will be performed using the Deep Impact spacecraft.

In addition to investigating comet Hartley 2, the spacecraft will point the larger of its two telescopes at nearby exosolar planetary systems in late January 2008 to observe several previously discovered planetary systems outside our solar system. It will study the physical properties of giant planets and search for rings, moons and planets as small as three Earth masses. It also will look at Earth as though it were an exosolar planet to provide data that could become the standard for characterizing these types of planets.

"The search for exosolar planetary systems is one of the most intriguing explorations of our time," said Drake Deming, EPOXI deputy principal investigator at NASA's Goddard Space Flight Center, Greenbelt, Md. "With EPOXI we have the potential to discover new worlds and even analyze the light they emit to perhaps discover what atmospheres they possess."

The mission's closest approach to the small half-mile-wide comet will be about 620 miles. The spacecraft will employ the same suite of two science instruments the Deep Impact spacecraft used during its prime mission to guide an impactor into comet Tempel 1 in July 2005.

If EPOXI's observations of Hartley 2 show it is similar to one of the other comets that have been observed, this new class of comets will be defined for the first time. If the comet displays different characteristics, it would deepen the mystery of cometary diversity.

"When comet Boethin could not be located, we went to our backup, which is every bit as interesting but about two years farther down the road," said Tom Duxbury, EPOXI project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Mission controllers at JPL began directing EPOXI towards Hartley 2 on Nov. 1. They commanded the spacecraft to perform a three-minute rocket burn that changed the spacecraft's velocity. EPOXI's new trajectory sets the stage for three Earth flybys, the first on Dec. 31, 2007. This places the spacecraft into an orbital "holding pattern" until time for the optimal encounter of comet Hartley 2 in 2010.

"Hartley 2 is scientifically just as interesting as comet Boethin because both have relatively small, active nuclei," said Michael A'Hearn, principal investigator for EPOXI at the University of Maryland, College Park.

EPOXI's low mission cost of $40 million is achieved by taking advantage of the existing Deep Impact spacecraft.

JPL manages EPOXI for NASA's Science Mission Directorate, Washington. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.

For information about EPOXI, visit:


Source: NASA Press Release 07-279

EPOXI Mission Trajectory



Click for full size image.

After its encounter with Tempel 1 (green arc), the Deep Impact spacecraft, now called EPOXI, continued in its orbit (yellow ellipse) around the sun that will bring it past Earth late this year. Along the way, there have been some trajectory correction maneuvers (TCMs) to adjust the spacecraft's path so that after the flyby it will be in an orbit (white circles) that will intersect with comet Hartley 2 (red arc) in 2010. During the flyby, the spacecraft will experience a gravity assist from Earth (blue circle) that will steal some of the orbital energy from the spacecraft, changing its orbit from the yellow path to the white one. Additional Earth flybys in 2008 and 2009 will refine the orbit even further.

2007 Earth Flyby

Image Credit: NASA/JPL-Caltech/UMD/GSFC/Tony Farnham

Source: UMD/NASA - EPOXI - Gallery

Lunar Calibration: HRI VIS Results



Click for full size image.

This white-light image of the Moon was taken by the NASA EPOXI mission as part of the Earth-Moon Flyby calibration of the instruments. The image was taken by the High Resolution Instrument (HRI) visual imaging camera at 22:00 UT on 29 Dec 2007, when the spacecraft was at about three times the Earth's distance from the Moon. To compensate for the defocus of the HRI telescope, the calibrated image was post-processed using 20 iterations of a modified Lucy-Richardson deconvolution procedure that includes wavelet noise dampening. The overly bright limb of the moon is the most noticeable artifact of the deconvolution.

Image Credit: NASA/JPL-Caltech/UMD/GSFC/Tony Farnham

Source: UMD/NASA - EPOXI - Gallery

Lunar Calibration: HRI IR Results










The December 2007 Earth gravity assist provided a unique opportunity for us to calibrate our instruments using the Moon. In particular, the Moon is very useful because it fills the entire field of view of the spectrometer. As planned, we smeared our exposures while scanning across the Moon. The results show that our spacecraft pointing and commanding was spot on. For the first time, either on the ground or in space, we now have uniform data at all wavelengths covering over 90% of the IR detector. We also made measurements which will allow us to cross-calibrate our instruments with telescopic data and, in the very near future, with a wealth of lunar measurements from new orbiting spacecraft. These data will significantly improve the science from EPOCh observations of Earth and the DIXI flyby of comet Hartley 2, as well as from Deep Impact's prime mission to comet Tempel 1. The EPOXI lunar calibration was very successful and nearly three years after launch it sure is nice to get new data from an old friend!

Technical Details: The top image does not appear to be all that exciting or beautiful, but is the critical measurement made during the 2007 Earth Flyby. We blurred the Moon at three different rates and then stitched the results together to make a "flat-field" -- a record of the instrument response to a uniform light source.
The middle and bottom images show the IR data reconstructed as images of the Moon at 1.5µm. These are very comparable to the VIS images (same resolution as MRI). The longer wavelength thermal IR was as we expected mostly saturated except at our shortest exposures (the little image "1005000").

Image Credit: NASA/JPL-Caltech/UMD/GSFC/Tony Farnham

Source: UMD/NASA - EPOXI - Gallery

The Lawrence Livermore National Laboratory press release is reproduced below:
Contact: Anne M. Stark
Phone: (925) 422-9799
E-mail: stark8@llnl.gov

LIVERMORE, Calif. -- Samples of the material picked up during the NASA Stardust mission indicate that parts of the comet Wild 2 actually formed in an area close to the sun.

New research by an international collaboration including Livermore researcher Saša Bajt analyzed noble gases within Stardust samples.The helium and neon isotope analysis suggests that some of the Stardust grains match a special type of carbonaceous material found in meterorites; hence both must have spent time in the same gas reservoir, which was close to the sun.


Following entry into the aerogel
at ~6 km/s (top) the particle was
subject to intense frictional heating
and fragmented, creating a prominent
bulbous cavity (middle) walled with
melted aerogel silica and small grain
fragments. Samples analyzed in this
study were taken from the cavity
wall; the triangular quarry left by
the sampling tool is visible at the
upper left. Two larger pieces
(diameters of ~10 and 15 mm)
of the original particle survived
to penetrate more deeply, along
trajectories marked by the narrow
individual tracks (bottom). Track
length is ~10 mm from entry to
deepest track terminus

About 10 percent of the mass of Wild 2 is estimated to be from particles transported out from hot inner zones to the cold zone where Wild 2 formed. The paper concludes that this is how these grains with unusual isotope ratios go incorporated into a comet.

Earlier research showed that the comet formed in the Kuiper Belt, outside the orbit of Neptune, and only recently entered the inner regions of the solar system.

Wild 2 spent most of its life orbiting in the Kuiper Belt, far beyond Neptune, and in 1974 had a close encounter with Jupiter that placed it into its current orbit. The Stardust spacecraft’s seven-year mission returned to earth in January 2006 with particles that are the same material that accreted along with ice to shape the comet about 4.57 billion years ago, when the sun and planets formed.

But during its lifetime, Wild 2 gathered material that formed much closer to the sun.

And the new research, which appears in the Jan. 4 issue of the journal Science, shows that some of the particles in Stardust are consistent with the early solar nebula.

“The unusual isotope ratio of helium and neon demonstrate that materials in comet Wild 2 had been much closer to the young sun than previously expected,” Bajt said.

Bajt, who studied tracks in aerogel caused by cometary particles rich in noble gases, used infrared spectroscopy, which is very sensitive in detecting organic molecules. She found none, at least not in the pieces of aerogel she examined. The group concluded that the carriers of the noble gases must be the refractory metal-metal sulfide-metal carbide grains, unlike what many expected would be a meteoritic Q-phase, which is known to be organic.

“That’s the first-order finding of the paper, and it’s a rather startling one,” said lead author Robert Pepin from the University of Minnesota.

The second conclusion is that the ion irradiation is the only known mechanism that could load the grains (by ion implantation) to the very high concentrations based on mass density estimates from X-ray absorption spectroscopy by Andrew Westphal and his team at the (Space Science Laboratory, UC Berkeley.

Noble gases are excellent tracers of contributions from various solar system volatile reservoirs and of physical processing of gases acquired from these reservoirs. Their elemental and isotopic compositions in primitive meteorites differ from those in the Sun. Planetary atmospheres display noble gas signatures distinct from both solar and meteoritic patterns.

X-ray absorption spectroscopy in the current study showed that the grains are composed primarily of high-temperature metal.

The X-ray and isotopic analyses point to gas acquisition in a hot, high-ion flux nebular environment close to the young sun.

Stardust is a part of NASA’s series of Discovery missions and is managed by the Jet Propulsion Laboratory. Stardust launched in February 1999 and set off on three giant loops around the sun. It began collecting interstellar dust in 2000 and met Wild 2 in January 2004, when the spacecraft was slammed by millions of comet particles, nearly halting the mission. It is the first spacecraft to safely make it back to Earth with cometary dust particles in tow.

Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy’s National Nuclear Security Administration.

Source: LLNL - press release

Contrary to scientists' expectations, much of the comet dust returned by NASA's Stardust mission formed very close to the young sun and was somehow differentiated from the other materials that are believed to have formed in the early solar system.


Artist concept of Stardust spacecraft.
Image credit: NASA/JPL-Caltech

When NASA's Stardust mission returned to Earth with samples from comet Wild 2 in 2006, scientists knew the material would provide new clues about the formation of our solar system, but they didn't know exactly how.

New research by scientists at Lawrence Livermore National Laboratory, Livermore, Calif., and collaborators reveals that, in addition to containing material that formed very close to the young sun, the dust from Wild 2 also is missing ingredients that would be expected in comet dust. Surprisingly, the Wild 2 comet dust samples better resemble a meteorite from the asteroid belt rather than an ancient, unaltered comet.

The team, using Livermore's SuperSTEM (scanning transmission electron microscope), specifically searched for two silicate materials in Stardust that are believed to be unique to cometary interplanetary dust particles: amorphous silicates known as Gems (glass with embedded metal and sulfides); and sliver-like whiskers of the crystalline silicate enstatite (a rock-forming mineral). Stardust is a part of NASA's series of Discovery missions and is managed by NASA's Jet Propulsion Laboratory. Stardust launched in February 1999 and set off on three giant loops around the sun. It began collecting interstellar dust in 2000 and met Wild 2 in January 2004, when the spacecraft was slammed by thousands of comet. It is the first spacecraft to safely make it back to Earth with cometary dust particles in tow.

The follow-on mission for the Stardust spacecraft, Stardust-NExT, is a low-cost mission that will expand the investigation of comet Tempel 1 initiated by NASA's Deep Impact spacecraft. JPL, a division of the California Institute of Technology, Pasadena, manages Stardust-NExT for the NASA Science Mission Directorate, Washington, D.C. Joseph Veverka of Cornell University is the mission's principal investigator. Lockheed Martin Space Systems, Denver Colo., manages day-to-day mission operations.

More information is online at _https://publicaffairs.llnl.gov/news/news_releases/2008/NR-08-01-05.html

More information about the Stardust mission is at _http://www.nasa.gov/stardust

Media contacts: DC Agle/JPL
818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle@jpl.nasa.gov

Source: NASA - Solar System - Features

NASA's Deep Impact spacecraft is aiming its largest telescope at five stars in a search for alien (exosolar) planets as it enters its extended mission, called Epoxi.


This is an artist concept of Epoxi, which uses the
Deep Impact spacecraft.
Image credit: NASA/JPL

Deep Impact made history when the mission team directed an impactor from the spacecraft into comet Tempel 1 on July 4, 2005. NASA recently extended the mission, redirecting the spacecraft for a flyby of comet Hartley 2 on Oct. 11, 2010.

As it cruises toward the comet, Deep Impact will observe five nearby stars with "transiting exosolar planets," so named because the planet transits, or passes in front of, its star. The Epoxi team, led by University of Maryland astronomer Michael A'Hearn, directed the spacecraft to begin these observations Jan. 22. The planets were discovered earlier and are giant planets with massive atmospheres, like Jupiter in our solar system. They orbit their stars much closer than Earth does the sun, so they are hot and belong to the class of exosolar planets nicknamed "Hot Jupiters."

However, these giant planets may not be alone. If there are other worlds around these stars, they might also transit the star and be discovered by the spacecraft. Deep Impact can even find planets that don't transit, using a timing technique. Gravity from the unseen planets will pull on the transiting planets, altering their orbits and the timing of their transits.

"We're on the hunt for planets down to the size of Earth, orbiting some of our closest neighboring stars," said Epoxi Deputy Principal Investigator Drake Deming of NASA's Goddard Space Flight Center in Greenbelt, Md. Epoxi is a combination of the names for the two extended mission components: the exosolar planet observations, called Extrasolar Planet Observations and Characterization (Epoch), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (Dixi). Goddard leads the Epoch component.

More than 200 exosolar planets have been discovered to date. Most of these are detected indirectly, by the gravitational pull they exert on their parent star. Directly observing exosolar planets by detecting the light reflected from them is very difficult, because a star's brilliance obscures light coming from any planets orbiting it.

However, sometimes the orbit of an exosolar world is aligned so that it eclipses its star as seen from Earth. In these rare cases, called transits, light from that planet can be seen directly.

"When the planet appears next to its star, your telescope captures their combined light. When the planet passes behind its star, your telescope only sees light from the star. By subtracting light from just the star from the combined light, you are left with light from the planet," said Deming, who is leading the search for exosolar worlds with Deep Impact. "We can analyze this light to discover what the atmospheres of these planets are like."

Deep Impact will also look back to observe Earth in visible and infrared wavelengths, allowing comparisons with future discoveries of Earth-like planets around other stars.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages Epoxi for NASA's Science Mission Directorate, Washington. The University of Maryland is the Principal Investigator institution. NASA Goddard leads the mission's exosolar planet observations. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.

For information about Epoxi, visit _http://www.nasa.gov/mission_pages/epoxi/index.html. More information about JPL is at _http://www.jpl.nasa.gov. More information about NASA programs is at _http://www.nasa.gov

Media contacts: DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle@jpl.nasa.gov

Nancy Neal 301-286-0039
Goddard Space Flight Center, Greenbelt, MD
Nancy.N.Jones@nasa.gov

Lee Tune 301-405-4679
University of Maryland, College Park
ltune@umd.edu

2008-021

Source: NASA - Missions - Epoxi