Shape Memory Alloys are often called memory metals because they seem to "remember" their former shape. A stretched SMA-wire contracts back to its previous form as a paper-clip when beeing heated, for example with a hairdryer or by applying an external electrical voltage.

This "intelligent" material's adaptability is based on two different crystalline strucures, whose transformation can be evoked on thermical and electrical basis. The memory-effect is already being used in many systems as an actuator, such as pneumatic ventiles in automobiles or as an actuating element in springs.

Since SMA are able to transfer great power without significantly wearing out on several 100.000 movements, they might also be used in locking systems to release interlocking and unlocking by electrical voltage of a spring made of SMA-wire.

The application of SMA is part of the research at the ISS.