Wild 2 and interstellar sample collection and Earth return

Stardust, launched in 1999, is the first mission designed to bring samples from a known, recently deflected comet, 81P/Wild 2, on 2 January 2004 and is also the first to capture newly discovered contemporary interstellar dust streaming through our solar system. The Stardust aerogel collector accomplishes Stardust's primary science and will be returned to Earth with its captured samples on 15 January 2006 in a reentry capsule. Wild 2 samples will be captured at 6.12 km/s and represent well‐preserved relics of the outer regions of our solar nebula and fundamental building blocks of our planetary system. Interstellar grains captured at velocities of less than 10 km/s are expected to survive intact and represent the main repositories of condensable elements that permeate the galaxy. These solid cometary and interstellar samples will be captured in two back‐to‐back sample collection trays filled with variable‐density aerogel. There are 132 silica aerogel capture cells of 3 cm and 1 cm thickness for the cometary and the interstellar sides, respectively. The aerogel capture cells were wedged into the sample collection trays and wrapped on all four sides with 100‐μm‐thick pure aluminum foil to facilitate aerogel cell removal. The total exposed Wild 2 surface area is 1039 cm 2 of aerogel and 153 cm 2 of aluminum foil. Results from a preliminary examination for the Wild 2 samples will be reported within 9 months of sample return and for the interstellar samples a year later. After preliminary examination the samples will be transferred to the NASA Office of the Curator and made available to the general science community.