Corbett also starred in a TV SF movie called "The Stranger". You'll probably have a hard time finding it but it's worth a look. It kind of seemed likt the pilot for a series never picked up. Corbett is an astronaut who finds himself on a strange duplicate of Earth where a full police-state runs the show. Also stars, Lew Ayes, Sharon Acker, Cameron Mitchell and the recently deceased Steve Frankin.
The Stranger scared the crap outta me as a kid. I've got a taped off of TV copy on VHS. I think it was the moons that freaked me out...