My memory is sketchy, but:
- A scene where two occupants of a space ship are standing under a retro rocket, which goes off and blasts the mask off one of the astronauts
- It ends up astronauts walking in this big empty area in front of a giant hairy brain (looks similar to the one that appears in a couple of lost in space episodes).
“Journey to the 7th Planet” (1962)?
Here is the trailer.
Sorry, I meant Journey to the Seventh Planet. The trailer doesn’t show it clearly, but there is a giant alien brain in this one. Below is the IMDb page:
https://www.imdb.com/title/tt0056127/?ref_=nv_sr_1