Evolution of a resettable Hold-Down and Release Actuator Based on SMA Technology

The evolution of a family of Hold-Down and Release Actuators (HDRAs) based on Shape Memory Alloys, called REACT, is presented in this work. The lessons learnt from previous developments have leaded to a complete redesign that has reached qualification status to TRL7 and flight heritage in some of the models. The new devices cover a wide range of operating loads and temperature ranges which make them suitable for their use in multiple space applications. In addition, the reset capability of REACT, thanks to the use of Shape Memory Alloys, is a key performance to improve the users’ integration and test activities at system level. The validation of a High Temperature SMA for these applications enables a wider operating temperature range than existing SMA products. The present work summarizes the status of each mechanism variant, the main qualification results and the lessons learnt during the evolution of the product.