Saturn 3
On Saturn 3, an older scientist born on Earth works with a young and beautiful assistant who has never been.
Their quiet life is interrupted when Keitel arrives — a man sent to help them.
They think he is a scientist.
He is a spy.
He has come with a robot that he build to take over the station.
He loses control when he interfaces with the robot because he's insane.
Eventually the robot kills him, then turns on the others.
It wants to kill the captain and keep the beautiful woman for itself — even though it's a machine, it has human sexual desires.