Fabrication of shape memory composites for non-explosive release mechanisms in space applications

Deployment of space structures, like telescopes and satellites, is performed by using pre-loaded springs and explosive charges for their release. In fact, most of the deployments are one-way, without repetition needs, and related mechanisms must be light, compact and easy to activate. Nevertheless, explosive actuators are very critical because of the excess of released energy and the risk of rebounds or damage. A new release mechanism has been prototyped by using shape memory polymer composites (SMPCs) for greater spatial sustainability. The non-explosive actuator (NEA) is made by laminating carbon fibre reinforced plies, shape memory polymer (SMP) interlayers and SMP foams. Its consolidation is achieved by one-step compression moulding. An embedded heater allows shape transition in thermo-mechanical cycling. The SMPC-NEA has been tested in memory and recovery tests at different voltages of the heater. It has been integrated into a 3D printed frame to prototype a full HDRM (hold-down release mechanism).