Rotary Actuator Based On Shape Memory Alloy for Operation in Mars

An ultra-low-weight rotary actuator based on Shape Memory Alloy technology has been developed for operation in Mars. The aim of this actuator is to provide an in/flight calibration system for the Dust Sensor instrument of the MEIGA-MetNet Mission that will perform airborne dust opacity measurements in the Mars surface. The actuator inserts a reflector stick in the optical path of the Dust Sensor, which uses IR measurements for dust characterization. This in/flight calibration system is used to compensate the error in the entire Dust Sensor acquisition chain. The complete actuator presented in this work, comprises a rotary mechanism actuated by a SMA, a position sensor, an electronic driver and a control algorithm. The total mass of the actuator is less than 9 gr and the total mass of the complete unit of the Dust Sensor is 42 gr.

A Qualification Model (QM) and qualification tests will be presented in this work. Results of Qualification tests will be presented in this paper in order to prove the fitness of the designed actuator as a simple and effective solution for space application, and for other where mass reduction and high reliability is demanding but movement high accuracy is not so important. A Flight Model of this device has already been developed and acceptance tests have been passed and will be presented in this work.

The actuator presented is designed and qualified to withstand an impact inertia up to 2000 g and work in a harsh environment with a temperature range of -90ºC to +30ºC under vacuum conditions. The use of Shape Memory Alloys on the designed actuator presents several advantages of lightweight, high force to weight ratio and low volume.