  Space systems such as communication satellites, earth observation satellites
and space telescopes require precise pointing to observe fixed targets over
prolonged time. These systems typically use reaction-wheels to slew the
spacecraft and gimballing systems containing motors to achieve precise
pointing. Motor based actuators have limited life as they contain moving parts
that require lubrication in space. Alternate methods have utilized
piezoelectric actuators. This paper presents Shape memory alloys (SMA)
actuators for control of a deployable antenna placed on a satellite. The SMAs
are operated as a series of distributed linear actuators. These distributed
linear actuators are not prone to single point failures and although each
individual actuator is imprecise due to hysteresis and temperature variation.
The system as a whole achieves reliable results. The SMAs can be programmed to
perform a series of periodic motion and operate as a mechanical guidance system
that is not prone to damage from radiation or space weather. Efforts are
focused on developing a system that can achieve one degree pointing accuracy at
first, with an ultimate goal of achieving a few arc seconds accuracy. Bench top
models of the actuator system has been developed and working towards testing
the system under vacuum. A demonstration flight of the technology is planned
aboard a CubeSat.
