Rescue Terra I(1982)

We have a serious problem on Terra I. The colonies sole purpose is to mine Zenbar Crystals which are used for 72% of Earth's energy production. Mining dangers plus security needed to safeguard crystal shipments required the creation of the most complex computer-controlled robotics system ever devised. This system had been doing a tremendous job. But... something is wrong. Crystal shipments have stopped, and returning crystal freighters have been destroyed by Terra I's own planetary defense system...