The two person crew aboard a space Shuttle, Jason Grant (Walter Koenig) and Ray Tanner (Bruce Campbell) come across a derelict spaceship in orbit. Grant goes out and discovers a humanoid corpse and also a strange egg shaped device that doesn't seem to be a part of the ship. He brings them back with him to his ship. They return to earth. Carbon dating says the human is 14,000 years old, which means there was an ancient advanced civilization. However, the government agent doesn't believe any of this. He thinks that Nasa is just trying to get a bigger budget. Meanwhile, the egg-like object they brought back opens up and it's a tiny robot. It begins utilizing parts from the lab and grows much larger. In fact, it uses parts of the original skeleton and also a person it kills, resembling sort of like a sloppy Borg from Star Trek. The Two astronauts are then sent to the moon, to find out about this robot's originals. It's there they uncover ancient ruins and come across more of the deadly robots. They also discover Mera (Leigh Lombardi), a young woman in suspended animation. When Tanner is killed and absorbed into one of the creatures it's up to Grant and Mera to stop the threat these mechanoids pose to Earth. In the end they do so-and in the last scene we see that these two are clearly together and she's learning to speak English. The movie has an open ending, like a lot of 80's creature features, with a closeup of the "egg" opening up in a junkyard and another robot emerging.
Overall I enjoyed this movie. It wasn't quite as good on a second viewing (the first was in '89), and I found Bruce Campbell still extremely irritating (not a fan) but it's still an entertaining flick that tries to be a bit different than other "space movies". It's also interesting it took nearly thirty years for the sequel (Moontrap: Target Earth).