AEROGEL

Aerogel is used on the STARDUST spacecraft to capture comet particles from Comet Wild 2.
This exotic substance has many unusual properties, such as low thermal conductivity, refractive index and sound speed - in addition to its exceptional ability to capture fast moving dust. Aerogel is made by high temperature and pressure-critical-point drying of a gel composed of colloidal silica structural units filled with solvents. Aerogel was prepared and flight qualified at the Jet Propulsion Laboratory (JPL). JPL also produced aerogel for the Mars Pathfinder and Stardust missions, which possesses well-controlled properties and purity. This particular JPL-made silica aerogel approaches the density of air. It is strong and easily survives launch and space environments. JPL aerogel capture experiments have flown previously and been recovered on Shuttle flights, Spacelab II and Eureca.

It is 99.8% Air

Provides 39 times more insulating than the best fiberglass insulation

Is 1,000 times less dense than glass

Photos: Courtesy NASA