New Pin Puller Based On SMA Technology for Space Applications

A new Pin Puller for space applications has been developed as an alternative to current devices. Pin Puller is a linear actuator that contains a pin deployed at the unactuated position and withdrawn at the actuated position. The new Pin Puller is able to work in a wider range of temperatures with respect to most Pin Pullers available in the market. The temperature restriction is one of the most critical limitations of current Pin Pullers for their use in space and other applications.

Two different Pin Pullers based on Shape Memory Alloys will be presented in this work, with different output force: 100N and 500N. These mechanisms are able to operate in the temperature range -90ºC to +125ºC and under hard vacuum conditions. The use of Shape Memory Alloys in the triggering actuators allows the developed devices to have minimum mass, one of the most critical requirements in space applications. Therefore, the 100N model is below 100gr, while 500N Pin Puller is lighter than 300gr.

Traditional Pin Pullers are based on pyrotechnic technologies, with their inherent limitations. The use of Shape Memory Alloys substituting pyrotechnic elements provides a number of advantages. These include: (1) there is no (or minimum) shock associated with SMA devices during its actuation; (2) the number of safety measurements during the installation and handling of SMA devices would be greatly reduced; and (3) deployment tests can be performed repeatedly without having to remove/reinstall pin pullers devices.

Engineering Models of both mechanisms have been built and tested and Qualification Models are currently under development and test. The main characteristics of these devices as well as the results of test campaigns will be reported in this work.