Development of Shape Memory Alloy (SMA) Actuated Mechanisms for Spacecraft Release Applications

Current methods of deploying spacecraft payloads typically employ explosive-type separation devices which do not address shock concerns and are not resettable without disassembly from the spacecraft or significant refurbishment of parts. Other separation mechanisms exist which eliminate explosives, but also do not offer reduced shock or the advantages of insitu resettability. Several new, shape-memory alloy (SMA) actuated release mechanisms have been developed for satellite release applications for loads of 500 lbf and greater. These mechanisms all offer fast, non-pyro releases and are completely testable and reusable while mounted on the spacecraft. The Qwknut and the Low-Force Nut (LFN) are suitable for release applications up to 3000 lbf, while the Fast-Acting, Shockless Separation Nut (FASSN) is suitable for higher load releases above 5000 lbf. FASSNs have been successfully prototyped for release applications of 80,000 lbf. Shawn H. Smith Applications for SMA mechanisms include satellite hold-down and release from the launch vehicle, hold-down and release of solar panels, and hold-down and release of cover panels and satellite appendages.