Note: A SMA wire actuated extremely long-lifetime release actuator using two ball-lock mechanisms

A shape memory alloy (SMA)-wire actuated release actuator with an extremely long lifetime was designed and validated. To ensure the ability of repeated actuation, two stages of ball-lock mechanisms were adopted to reduce the load in the SMA wire. In addition, a length-increasing design of the SMA wire was employed. Validation tests, including function tests, vibration tests, shock tests, and thermal vacuum tests were conducted on prototypes. According to the test results, the actuator can release a maximum preload of 15 kN and has a lifetime of more than 693 cycles. Furthermore, the actuator can function well, even under severe thermal and vibration environments.