for National Geographic News
Scientists say they're thrilled and awed by their first glimpse at the comet particles and samples of interstellar dust returned by the Stardust spacecraft.
Stardust's canister of samples dropped safely to Utah's desert floor Sunday.
"Now we can bring to mankind a very unique glimpse of the beginning of our solar system," said Peter Tsou, the mission's deputy principal investigator, at a mission briefing today at NASA's Johnson Space Center in Houston, Texas.
"In fact I will say tiny samples from a distant comet open giant windows of our past," Tsou added.
The canister's return marked the final leg of the spacecraft's 7-year, 2.88-billion-mile (4.63-billion-kilometer) flight. (Watch a video of the Stardust mission.)
During its mission, Stardust collected particles swirling off the comet Wild 2, as well as samples of interstellar dust streaming into our solar system from other parts of the galaxy (interactive solar system map).
The spacecraft collected the particles using a tennis-racket-shaped device filled with a light, porous material called aerogel. The light, porous gel is 99.8 percent air and is capable of trapping delicate particles without damaging them.
Donald Brownlee, Stardust's lead scientist, called the collected particles a "cosmic treasure."
After the canister touched down in the Utah desertjust hours before a fierce snowstormscientists recovered the capsule and shipped it to Johnson Space Center.
Researchers got their first peek at the contents Tuesday.
Brownlee said scientists gathered around the racketlike collector and were awed at what they saw.
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