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A guy on a space ship picks up a distress call, a boy is stranded on a planet with a hostile environment. He & his crew go to the rescue, stopping on the way to pick up an old man who comes with them. Most of the top of the old guy's skull is metal, from an old injury.
They've various adventures on the way (their ship is boarded by pirates/bandits/hostile forces at one point).
They get to the planet with the boy. They've limited time to save him as the planet is being moved back in time. (I can't remember why) When they find the boy, he's being attacked by giant wasp-type-things.
The boy is injured on the top of his head. The old guy dies protecting him. The boy gets shifted back in time with the planet and - you guessed it - survives, grows up and turns out to be the old guy.
Now that I've remembered some of it, the bits I can't remember are driving me crazy. I'd love to see this again, if I could identify it I might be able to track down a copy.
I'd swear I saw this mid 80's on morning TV, but it I could be out by 5 years either way. Thanks