I have vague memories of my dad and brother watching a movie, or possibly a TV show in the mid to late 1980’s. An astronaut is on a space-walk and something unexpected happens where he is exposed to cosmic rays or some other weirdness.
He is brought back to Earth and shenanigans ensue. I left the room at this point because it had scared me, I fully expect to find it was about as frightening as Bambi, but I was pretty young.
Astronauts coming back to earth having had weird things happen to them is a common theme, going back into the 1950s. I don’t know which 1980s movie you saw, but here’s a list:
**The Quatermass Xperiment ** (known as The Creeping Unknown in the US) – 1955
First Man Into Space – 1959
The crawling Hand – 1963
Monster a Go-Go – 1965
The Incredible Melting Man – 1977
Xtro – 1982
Xtro 2 – 1990
The Astronaut’s Wife – 1999
I’d bet "The Incredible Melting Man was the film you described, based on the date, although I don’t think there’s a space walk in it. The Astronaut’s Wife has a space walk in it, though, but it’s much later.