It turns out that Ridley Scott originally wanted to end
Alien with what would've been a huge blow to fans who just spent the the last two hours hoping at least one of the Nostromo's crew members would survive the Xenomorph's assault. Here's what almost happened in
Alien's ending.
In Scott's original ending idea for
Alien, the grappling gun has no real effect on the Xenomorph, and it then moves forward, crashing onto Ripley. The Xenomorph busts straight through her space helmet, and rips her head clean off. As if that wasn't depressing enough, the alien monster would then be seen pressing buttons on the shuttle's dashboard, before mimicking Captain Dallas' voice saying "I'm signing off." Presumably, the Xenomorph would then wait to be "rescued," by another hapless human crew. While studio executives often get a bad rap, in this case it was executives at Fox who vetoed the dark ending with Ripley's death, even threatening to fire Scott from the film if he refused to change it. See, not all executive meddling is bad.
https://screenrant.com/alien-movie-ripley-death-original-ending/