This is an original production used final draft script from Roger Corman's cult classic Galaxy of Terror with the film's working title of "QUEST" by Marc Siegler and Bruce D. Clark.
It is a clean script dated 2/23/1981 and is on white paper. It also looks to be a copy of a cut & paste script where they literally pasted in new sections and blanked out others.
Originally titled Planet of Horrors, it was difficult to get any actors interested so the name of the ship Quest was chosen as the working title.
It is very similar to the final film although the script contains longer scenes with additional dialogue. One difference is the character Quuhod played by actor Sid Haig. He didn't think the dialogue in the script matched the character of Quuhod, so he asked Roger Corman if he could play Quuhod as a near mute instead and only says a single line in the whole movie. The script contains some of that additional dialogue.
The infamous worm rape scene is just a messy death in this draft.
It also contains a wonderful line from Ilvar that never made the final cut: "The grandest mammaries in the galaxy"
Galaxy of Terror was Corman's Alien homage (read ripoff) and is notable for its production design by a young James Cameron including Alec Gillis and Robert Skotak and its in camera effects and was clearly an influence on Aliens.