Dust Collector Grid With Aerogel
Collection of cometary particle samples is accomplished by simply exposing blocks of aerogel to the material it encounters during spaceflight.
The dust collector media consists of blocks of 1 and 3 cm thick underdense, microporous silica aerogel mounted in modular aluminum cells. This is similar to what was used for previous exposures during Shuttle and MIR experiments. For the Stardust mission, cells in a grid holding aerogel are mounted on a two-sided, tennis racket-shaped array that will deploy from the Sample Return Capsule. After exposure, the array will fold compactly for stowage inside the sample Earth return capsule for the trip back to Earth.
Image above: Aerogel dust collector. Image credit: NASA/JPL.
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One side of the aerogel will be used to collect samples during the comet encounter and the reverse side - sometimes called the "B-side" - will be used for interstellar collection. The useful collecting areas are identical, with 1000 cm2 for interstellar dust grains and 1000 cm2 for cometary dust. These collectors are totally inert and only need to be exposed and then stowed after they are used.