Marooned (1969)

Revealing mistake: Early in the film Gene Hackman tests a rocket-powered backpack outside the space station. He slowly spins sideways through a complete circle, but instead of each side of his body being lit up in turn as it's pointed towards the sun, the light stays constant throughout the maneuver, showing that the makers just took a photo of Hackman and rotated it.

Continuity mistake: The Russian spaceship approaches the stranded 'Ironman 1' capsule, and as it moves across and fills the screen, it blocks the bright sun directly behind it. The following shot shows it moving away from that position and the sun is now nowhere to be seen.

Kit Sullivan

Factual error: In nearly every scene depicting someone or something in weightlessness (zero gravity), objects tend to start moving randomly without any initial propulsive force or, when already in motion, to been seen to randomly change direction of movement with no outside force acting upon them. Both of these are impossible in a true zero-G environment.

Kit Sullivan

Clayton Stone: Jesus, fifty-five minutes... We'll be pretty cold by then.
Buzz Lloyd: Well, one of us' gonna have to go. I mean uh... that's what we're talkin' about, isnt it? One of us goes and the... other two stay. What... what are we gonna do?
Clayton Stone: Alright look. Let's do this scientifically: two big guys throw the little guy out, okay?

Ted Dougherty: Listen, all you guys gotta worry about is where you want me to set you down after I make the transfer. Go on, pick your spot. Edwards? Vegas? How about the beach at Malibu?