A shape-memory alloy actuated valve for space propulsion systems

Pyrovalves are currently used in space propulsion systems for their fast response, high reliability and low ratio between mass and actuation force. However they are hazardous, single use items, their operation induces shocks and can generate gases or particles, which can contaminate the propellant line. These drawbacks could be potentially eliminated by the use of shape-memory actuators. The paper reports on the development of a multiple-use, manually resettable shape-memory alloy actuated space valve. A demonstrator has been built and tested. The valve has shown high reliability, in particular regarding cycling stability, vibration and leak tightness. In response to a number of spacecrafts failures in which pyrovalves are probably responsible, a first step in the direction of finding alternatives to these devices has then been accomplished. It opens new perspectives for spacecraft propellant line design.