Stardust: Cometary Paydirt
|Stardust spacecraft beaming back its images soon after surviving its Wild- 2 comet encounter.
Scientists at the Johnson Space Center in Houston were excited and awed by what they saw when the sample-return canister from the Stardust spacecraft was opened.
"It exceeds all expectations," said Donald Brownlee, a University of Washington astronomy professor who is principal investigator, or lead scientist, for Stardust. "It’s a huge success. We can see lots of impacts. There are big ones, there are small ones."
Stardust returned to Earth in a spectacular re-entry early Sunday after a 7-year mission to collect particles from comet Wild 2 and samples of interstellar dust streaming into our solar system from other parts of the galaxy. The comet dates from the formation of the solar system 4.6 billion years ago.
Brownlee calculated there might be more than a million microscopic specks of dust embedded in Stardust’s aerogel collector. Aerogel, a remarkable material that is as much as 99.9 percent empty space, greatly reduced the stress of impact on the particles, he said. The carrot-shaped tracks of much larger particles are visible in the aerogel from several feet away, Brownlee said, and in some of the tracks the black comet dust is visible at the end of the track. One track, he said, "is almost large enough to put your little finger into it."
|Comet Wild 2 imaged by Stardust just after flyby. The image highlights the remarkably rugged surface of the comet, which in close-up stereo views shows hardened impact craters, cliffs, and mesas in the landscape.
Scientists will search the aerogel grid for dust samples, and more than 65,000 people have signed up to help in a project called Stardust@home, in which their home computers will examine images of tiny sections of the aerogel grid looking for dust particles.
The Johnson Space Center will be the curator of the Stardust samples, and as many as 150 scientists worldwide are waiting to study them.
"Stardust is a phenomenal success," Brownlee said.
Past missions that have flown by a comet have been: NASA’s ICE mission in 1985, the two Russian Vega spacecraft and the two Japanese spacecraft Suisei and Sakigake that were part of the armada that visited Comet Halley in 1986; NASA’s Deep Space 1 flew by Comet Borelly in 2001 and NASA’s Stardust, which flew by Comet Wild 2 and has captured samples of the comet’s coma. On Valentine’s Day, 2001, the Near-Shoemaker spacecraft successfully landed on the asteroid, Eros. Its remarkable journey–to soft-land on a peanut shaped asteroid – about 176 million kilometers (109 million miles) from Earth, prompted Andrew Cheng, NEAR Project Scientist, to note: "On Monday, 12 February 2001, the NEAR spacecraft touched down on asteroid Eros, after transmitting 69 close-up images of the surface during its final descent. Watching that event was the most exciting experience of my life."
– New Horizons, Pluto and moon Charon flyby, mapping to outer solar system cometary fields and Kuiper Belt
– Dawn, Asteroid Ceres and Vesta rendezvous and orbiter, including investigations of asteroid water and influence on meteors
– Kepler, Extrasolar Terrestrial Planet Detection Mission, designed to look for transiting or earth-size planets that eclipse their parent stars [survey 100,000 stars]
– Europa Orbiter, planned Orbiter of Jupiters ice-covered moon, Europa, uses a radar sounder to bounce radio waves through the ice
– Japanese SELENE Lunar Orbiter and Lander, to probe the origin and evolution of the moon
– Japanese Planet-C Venus Orbiter, to study the Venusian atmosphere, lightning, and volcanoes.
– Mars Scout mission, final selection, Phoenix
– French Mars Remote Sensing Orbiter and four small Netlanders, linked by Italian communications orbiter
– BepiColumbo, European Mercury Orbiters and Lander, including Japanese collaborators, lander to operate for one week on surface
– Mars 2009, proposed long-range rover to demonstrate hazard avoidance and accurate landing dynamics
Related Web Pages
Harpooning a Comet
Comet Cruise Glimpses Earth
Coma for Halley’s Comet
The Great Debate: Is Complex Life Common in the Universe?
"Bring ’em Back Alive – or at Least Carefully" Essay by John Rummel and Margaret Race
Early Wild Success for Stardust
Telescopes for Stardust