Development of a shockless thermally actuated release nut using elastic memory composite material
Spacecraft require a variety of separation and release devices to accommodate separation from the launch vehicle and deployment of solar arrays and other appendages. Pyrotechnic release devices produce high shock and contamination, are hazardous and costly to handle, and are not re-settable (i.e., can only be used once). Mechanical release devices can overcome most of these disadvantages, but they tend to be complex and costly. The present paper describes an innovative, non-pyrotechnic, lightweight, mechanically simple, and fully re-settable retention and release device called the Shockless Thermally Actuated Release Nut (STAR Nut). The key active element in the STAR Nut is a high-strength, Elastic Memory Composite (EMC) cylinder that is designed to change shape upon heating. The paper presents: 1) a set of system requirements and a conceptual design for the STAR Nut, 2) performance analyses of the EMC cylinder, and 3) results from fabrication and testing of EMC laminates.