Probably hypergolics for propulsion,,,
http://en.wikipedia.org/wiki/Hypergolic_propellant
electrically powered gyroscopes for attitude control,
And solar panels to operate on-board systems. In theory, the machine could remain dormant forever until it was given the right radio commands, as long as the sun was shining. In practice, things degrade in the space environment, lubricants, insulators, plastics, even metals.