Precision Pointing of Antennas in Space Using Arrays of Shape Memory Alloy Based Linear Actuators

TL;DR

This paper explores using shape memory alloy actuators for precise antenna pointing in space, aiming for high reliability and radiation resistance over traditional motor-based systems.

Contribution

It introduces a novel SMA-based distributed linear actuator system for satellite antenna pointing, emphasizing reliability and space environment resilience.

Findings

System achieves reliable pointing despite individual imprecision.

SMA actuators are resistant to radiation and space weather effects.

Prototype demonstrates potential for 1-degree accuracy, aiming for arc-second precision.

Abstract

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.