Hypervelocity particle capture

Abstract NASA has used aerogel in several space exploration missions over the last two decades. Aerogel has been used as a hypervelocity particle capture medium (Stardust) and as thermal insulation for the Mars Pathfinder, Mars Exploration Rovers, and Mars Science Lander. Future applications of aerogel are also discussed and include the proposed use of aerogel as a sample collection medium to return upper atmosphere particles from Mars to earth and as thermal insulation in thermal-to-electric generators for future space missions and terrestrial waste-heat recovery technology. 

Hypervelocity Particle Capture 32.2.1. Initial on Orbit Studies... 

The Stardust Mission was designed around the fact that low-density aerogel had been demonstrated to be an excellent hypervelocity particle capture medium [17]. The mission plan was to transport a grid of aerogel cells into space, rendezvous with a comet, capture material from the comet in the aerogel, and return the collected samples to the earth [20]. The primary science requirement of the mission was that 1,000 cometary particles, 15 pm or larger in diameter, be captured and returned to Earth. 

Figure 32.6. Proposed SCIM collection modules containing silica aerogel with a density of 20 mg/cc for hypervelocity particle capture.

Analogous aerogels are also used in space research as a capture medium for cosmic dusts. These hypervelocity particles enter the fine structure of the aerogel which dissipates their kinetic energy. Consequently particles having a few micron size can be captured intact and easily located within the transparent aerogel (Tsou, 1995). 

Figure 32.4. Entry track produced by the capture of 50 pm hypervelocity fine particle in silica aerogel. The aerogel shown was gradient density 15-50 mg/cc.

Figure 32.8. After hypervelocity capture of meteoritic particle, this keystone was cut and removed from the bulk sample of RF aerogel. Approximate dimensions are 600 by 250 by 75 pm.

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