1969's classic Marooned. Three astronauts can't return to Earth because their retro rocket won't fire and they have only 42 hours of air left. NASA helped a great deal on this film and it shows. This movie was based on the Skylab mission that actually took place four years later. This movie could've happened for real. In fact, I don't regard this as Sci-Fi, but as a straight drama that happened to take place in low Earth orbit. All-star cast includes Gregory Peck, Gene Hackman, Richard Crenna, James Franciscus, David Janssen and Mariette Hartley. Won Oscar for special effects. There is genuine tension and drama as NASA tries to get the astronauts down and there is a full-fledged hurricane.
I taped this from Turner Classic and Robert Osbourne said it cost nine million bucks to make, 2001: A Space Odyssey cost ten million.