Short answers, pulled from the story.
Stardust was a NASA probe launched on the 7th of February 1999 to collect dust samples from the coma of Comet Wild 2 and return them to Earth for analysis. It was the first sample-return mission of its kind. The sample capsule returned to Earth on the 15th of January 2006.
The Stardust Sample Return Capsule re-entered Earth's atmosphere at 46,440 kilometers per hour, the fastest reentry speed ever recorded for a human-made object. It decelerated from Mach 36 to subsonic speed in just 110 seconds, with peak deceleration reaching 34 g.
Analysis of the Wild 2 samples found crystalline silicates including olivine and pyroxene, organic compounds containing biologically usable nitrogen, and glycine, an amino acid and building block of life. Scientists also found evidence of iron and copper sulfide minerals that must have formed in the presence of liquid water.
Aerogel is a silicon-based solid where 99.8 percent of the volume is empty space, allowing it to stop fast-moving particles without destroying them. Stardust's tennis-racket-sized collector tray held ninety blocks of aerogel providing more than 1,000 square centimeters of capture surface to trap grains from Wild 2's coma.
Stardust-NExT, approved on the 3rd of July 2007, redirected the spacecraft to fly past Comet Tempel 1 and photograph the crater left by the Deep Impact mission in 2005. The encounter occurred on the 15th of February 2011, with the spacecraft passing at 181 kilometers and capturing an estimated 72 images.
The Stardust Sample Return Capsule is on display at the National Air and Space Museum in Washington, D.C. It began exhibition there on the 1st of October 2008, the 50th anniversary of the establishment of NASA, and is displayed in sample collection mode alongside a sample of the aerogel used to collect the comet dust.