Abstract: Spacecrafts need release devices to realize space release function. The traditional pyrotechnic release devices have the drawbacks of high shock and contamination. NASA-developed release device with shape memory alloy (SMA) column has the disadvantages of long release lasting time and unavailability of reset. Based on the research of NASA, a design scheme of SMA space release device with segemented nut form is proposed, and the corresponding design method is developed for the core part of the release device, i.e. driving unit. Finially, the prototype is developed and the function and synchrony tests are carried out. The results show that under 6V DC power supply, the device can finish release function within 0.3 s, and when two devices are used, they are almost release at the same time. The difference of release lasting time for two devices is less than 0.04 s. The space release device developed has the advantages of small size, short release lasting time, easy reset and synchronization, thus having great potential in engineering application.

Key words: Constitutive relation, Segmented nut, Shape memory alloys, Smart structures, Space release device