[PAR_WIG1350]

Muscle wire (Nitinol/SMA) would be cool for light duty applications. It would be lighter than either pneumatics or servos and would be perfect for releasing latches that keep the robot in starting configuration. Adding a pneumatics system just for that would be a terrible use of weight and space, and in some situations, so would servos or solenoids. SMA actuators take up no more space than a piece of fishing line, require very little additional hardware, are easy to integrate even if they are not accounted for in the design, and weigh next to nothing.