From: Ames Research Center
Posted: Friday, August 10, 2007
Dr. Scott Sandford presented a Director's Colloquium about samples returned to Earth from a comet named Wild 2 by the Stardust spacecraft.
The informative presentation was especially unique because the audience got the chance to wear 3D glasses and view the comet in 3D. At one time, probably in 1974, this comet had a close encounter with Jupiter, whose gravity altered the comet's orbit so that it now comes closer to the Earth. Wild 2 is different because of this and has a far more prestine outer layer than other comets. There are three podcasts from Sandford available online (podcast 1, podcast 2, podcast 3).
The Stardust capsule launched on Feb. 7, 1999 and traveled a total distance of 2.88 billion miles on its seven-year journey. It came back with the first solid sample return from outside the Earth-moon system in history. Aerogel, the world's lowest density solid, was used to collect the samples. The Stardust spacecraft encountered the Wild 2 comet on Jan. 2, 2004, collected samples from its coma (the cloud of gas and dust that surrounds the central nucleus), and then stored the samples inside a capsule. After collecting the samples, the capsule experienced the fastest reentry into the Earth's atmosphere ever attempted.
On Jan. 15, 2006 the capsule parachuted into the Utah Test and Training Range in Utah where it bounced four times on landing but did not damage any of the samples inside. In the Dec. 15, 2006 issue of Science contained a series of articles about what we learned from the Stardust mission. We learned that when the solar system formed. There was a lot of "mixing" going on. We know this because the specimens are so varied. For example, the samples contain both high temperature and low temperature components. Also, comets, or at least Comet Wild 2, really are repositories of relatively unprocessed early solar system composition. Stardust samples are a legacy that will be used by scientists for generations to come.
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