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Spacecraft require a variety ofmechanisms to accomplish mission-related functions such as deployment, articulation, and positioning. Current off-the-shelf devices such as pyrotechnic separation nuts, paraffin actuators, and other electromechanical devices may not be able to meet future satellite requirements, such as low shock and vibration, and zero contamination. The Air Force Research Laboratory (AFRL), with corporate and government partners, has developed Shape Memory Alloy (SMA) spacecraft release mechanisms and hinges as alternatives. In order to meet future goals, the SMA devices have been designed to reduce shock and vibration, reduce parts, and eliminate pyrotechnics. This paper will focus on descriptions and results of on-orbit SMA mechanism experiments and applications. AFRL has flown SMA release devices as part ofthe Shape Memory Alloy Release Device (SMARD) experiment on MightySat I. The SMARD experiment, that compared the shock and release times oftwo SMA devices with those of current off-the-shelf devices, was conducted in May 1 999 with extremely successful results. In addition, four AFRL funded SMA release mechanisms successfully deployed the Air Force Academy FalconSat spacecraft from the Orbital Sub-Orbital Program Space Launch Vehicle (OSP-I) in January 00. AFRL has also conducted an on-orbit experiment with SMA hinges. The hinges were flown as part of the Lightweight Flexible Solar Array (LFSA) program, that was a joint AFRLIDARPA/NASA/Lockheed Martin program to develop innovative solar array technologies. Six SMA hinges were launched as part of the LFSA experiment on the Space Shuttle Columbia (STS-93) in July 1999 with successful results.

The Air Force Office of Scientific Research, the Defense Advanced Research Projects Agency, NASA, and industry are jointly sponsoring the development and launch of 12 university nanosatellites. Through this project, the 10 selected universities will conduct innovative, low-cost experiments to explore the military usefulness of distributed satellite systems and micro and nanotechnologies in support of the Air Force Research Laboratory's TechSat 21 distributed radar aperture collaborative microsatellite constellation. Among the technologies to be explored are formation flying, enhanced communications, miniaturized sensors and bus technologies, attitude control, and distributed satellite capabilities. Launch is planned for late 2001. This paper provides some detailed information on the technologies and science objectives of each of the nanosatellites.