A reusable locking and releasing mechanism for space optical payloads

A locking and releasing mechanism actuated with shape memory alloy (SMA) wire is proposed to meet the locking and releasing requirements of space optical payloads. This mechanism uses a kinematic chain composed of contacting rollers to transfer a high preload, and the releasing action can be triggered with a small driving force generated by SMA wire. In order to verify the proposed design scheme of the mechanism, a prototype is developed, and the locking and releasing test, high environment temperature adaptability test are carried out. The test results show that the mechanism can maintain locking stage under a preload of 15 kN, and release successfully under a DC current from 4.0 A to 6.0 A, the corresponding release time are 1.53-0.61 s. In addition, the mechanism won't release unexpectedly when the environment temperature is below 79 ℃. Based on the test results, the mechanism has the advantages of high preload-carrying capacity, low-shock, no pollution and reusability, it can be widely used as a locking-release device for space optical payloads.