Aerogel Fact Sheet

The NASA Vision The NASA Mission To improve life here, To understand and protect our home planet, To extend life to there, To explore the universe and search for life, To find life beyond To inspire the next generation of explorers Aerogel ...as only NASA can Mystifying Blue Smoke

At first sight, aerogel resembles a hologram. An JPL’s second application of aerogel is spacecraft in- excellent insulator, aerogel has the lowest density sulation. Because aerogel is mostly air, an effective Property Silica Aerogel Silica Glass of any known solid — one form of this extraordi- thermal insulator is contained within its porous nary substance is actually 99.8 percent air and silica network. This presents an excellent thermal Density (kgm3) 5 – 200 2300 0.2 percent silica dioxide (by volume). Aerogels barrier to protect the spacecraft against the ex- Specific Surface Area 500 – 800 0.1 have open-pore structures similar to honeycomb, treme cold of deep space. The Mars Pathfinder (m2/g) but in fact they are low-density, solid materials mission used aerogel to protect the electronics Refractive Index at with extremely fine microstructures. Typically sili- of the Sojourner rover against the frigid Martian 1.002 – 1.046 1.514 – 1.644 632.8 nm con-based like ordinary glass, or carbon-based like environment during Sojourner’s 1997 travels on common organic synthetics, aerogels possess the red planet. Each of the twin Mars Exploration Optical unique physical properties (see table). The unique Rovers, scheduled to land on Mars in early 2004, Transmittance 90% 99% characteristics of aerogels are being applied to employs aerogel for thermal insulation of the bat- at 632.8 nm tery, electronics, and computer in the chassis, or meet new technological demands. Coefficient of warm electronics box. Thermal Expansion ~2 x 10–6 10 x 10–6 Aerogel was discovered in the late 1930s by 1/C at 20–80 deg C chemist Samuel S. Kistler. Since then, numerous JPL is currently investigating a variety of future attempts have been made to further understand applications for aerogel. Discussions and experi- Thermal and develop it. At NASA’s Jet Propulsion Labora- ments are ongoing regarding its use as a thermal Conductivity 0.016 – 0.03 1.2 (W/mK) at 25 deg C tory (JPL), aerogel technology has found two pri- insulation material for light aircraft and spacecraft. mary applications. The first is the capture of dust Aerogel’s large surface area makes it a potential Sound Velocity (m/s) 70 – 1300 5000 – 6000 particles from comet Wild 2 (pronounced “Vilt 2”) basis for chemical sensors. Aerogel may also find Acoustic Impedance a home in areas such as sporting equipment and 104 107 by the Stardust sample return mission. The par- (kg/m2/s) ticles gradually decelerate as they bore deeper into architectural design through corporate and aca- Electric Resistivity the threadlike silica network of Stardust’s gradient- demic contacts. 18 15 (ohm-cm) 1 x 10 1 x 10 density aerogel, so that the samples sustain mini- mal damage while being collected for return to For more information about aerogel, visit Dielectric Constant 1.008 – 2.27 4.0 – 6.75 Earth for scientific study in 2006. http://stardust.jpl.nasa.gov at 3–40 GHz

Development Timeline

1930 1940 1980 1997 1999 2004 2004 2006 2008 Future uses. Aerogel discovered. Aerogel first Scientific uses Sojourner insulation. Stardust Mars Exploration Stardust encounter Stardust sample marketed commercially. of aerogel. launch. Rovers. with comet Wild 2. returns to Earth.

JPL 400-1119 9/03