DEFCON-4 (1985)
Canadian post-apocalyptic film also starts with three astronauts returning to a war-ravaged Earth. In this case, one's a woman, and they're aboard a secret space station orbiting the planet, ready to rain down nuclear death on the commies when WWIII breaks out.
(In an effective early scene, one of the men gets a videotape from his wife, who has no idea where he is or if he's even alive.)
It does, of course. The trio, who have been up there more than 400 days, debate whether to return to Earth. This becomes a moot point when somebody takes over the station's control by remote control and brings it down. Once again, one of them is killed right away. In this case, by "terminals," who use him for food.
That's the least of the worries of the two survivors. There's also a survivalist guy with a homemade armored vehicle and a gang of paramilitary types under the command of a very young guy. Not to mention the fact that one of the nuclear bombs on the station, now on Earth, failed to launch and is ticking down the seconds until it explodes . . .
Obviously done on a modest budget (although not anywhere near as poverty-stricken as the previous film) but with interesting characters and plot twists. The default hero starts off panicky and slowly evolves into someone desperately fighting back.