After stealing the Voltronic Galaxer from the Haley Observatory, Megatron, Starscream and Thundercracker boarded Astrotrain and headed for the Moon. While Astrotrain stayed parked outside, the other three Decepticons installed the Voltronic Galaxer in the machinery inside the moonbase. Done, Megatron looked outside and spotted the Autobot Cosmos, who had only just discovered the moonbase, and sicced Astrotrain on him.