Surely there cannot be a movie starring Cindy Williams. No, really, there was — and stop calling her Shirley. My sister and I had this on VHS; it’s a charmer called Spaceship (1982), and it’s so eternal that I can only find it on IMDB under its alternative title, The Creature Wasn’t Nice.
If you can find it, I do recommend watching it. It’s not conventionally good, but there are some great shlocko lines and truly amateur writing. Also, Leslie Nielsen plays the captain, so there’s that.