User blog comment:Damac1214/Some Zombie Polls/@comment-1263839-20130424212251/@comment-1263839-20130425061924

They came out and said "It was aliens!" by the fact that it was there before any Human was ever on the Moon, and the MPD obviously made by a sentient being. We've never seen time travel go back in time, so Aliens!? is the more likely suspect.

As for Samantha (and Maxis too before he became a computer), take into account the whole absolute zero temperature of space... she'd be dead pretty much instantly or barely capable of movement.