Foam sensor structures would be self-deployable and survive hard landings

NASA Tech Briefs, Nov 2003 by Sokolowski, Witold, Baumgartner, Eric

NASA's Jet Propulsion Laboratory, Pasadena, California

A document proposes systems of sensors encased in cold hibernated elastic memory (CHEM) structures for exploring remote planets. The CHEM concept was described in two prior NASA Tech Briefs articles, including "Cold Hibernated Elastic Memory (CHEM) Expandable Structures" (NPO-20394), Vol. 23, No. 2 (February 1999), page 56 and "Solar Heating for Deployment of Foam Structures" (NPO-20961), Vol. 25, No. 10 (October 2001), page 36. To recapitulate: Lightweight structures that can be compressed for storage and later expanded, then rigidified for use are made from foams of shape-memory polymers (SMPs). According to the instant proposal, a CHEM sensor structure would be fabricated at full size from SMP foam at a temperature below its glass-transition temperature (T^sub g^). It would then be heated above T^sub g^ and compacted to a small volume, then cooled below T^sub g^ and kept below T^sub g^ during launch, flight, and landing. At landing, the inelastic yielding of the rigid compacted foam would absorb impact energy, thereby enabling the structure to survive the landing. The structure would then be solar heated above T^sub g^, causing it to revert to its original size and shape. Finally, the structure would be rigidified by cooling it below T^sub g^ by the cold planetary or space environment. Besides surviving hard landing, this sensor system will provide a soft, stick-at-the-impact-site landing to access scientifically and commercially interesting sites, including difficult and hard-to-reach areas.

This work was done by Witold Sokolowski and Eric Baumgartner of Callech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Physical Sciences category.

NPO-30654