Two - way SMA actuators for space application: performances and reliability

Abstract

We demonstrate for the first time highly reliable actuators based on two-way shape memory effect (TWSME). Under life test, our actuators endure 300.000 loading cycles without performance degradation (fade out or amnesia). Further, we developed manufacturing technology which enables programming of the actuator deformation in austenite and martensite phase within the tolerance of ±6 %. Novel actuators were qualified at the breadboard model level as the first TWSME actuators for space applications at the European Space Agency. The actuators are based on 50μm thick NiTi alloy foil, doped with Cu. These novel actuators for the spacecraft thermal management system can reduce the mass of vane louvers from the current 4-5 kg/m2 to less than 500 g/m2. Further, due to the application of special optical coatings, the new louvers demonstrate better heat rejection efficiency than the existing systems.