Better than average for Sci Fi movies, but -2 points for two particular reasons Most Sci Fi movies are terrible, not even remotely plausible. This one was better than average. Yes, the rooms on the spaceship were large than necessary, which would not happen at this point in time. And there were various other small items like that.
But mostly it was fairly plausible at the time it was created.
I would have given it an 8 (quite a high score for me), but I subtracted two points for the following reasons:
1) The ending was very abrupt and I didn't understand it. It is not an action-packed Hollywood-block-buster-type film (which is a positive). It attempted to explain what was happening every step of the way. Until the end. I still don't understand what happened. To abrupt and cryptic.
2) The main character is a guy maybe 50 years old and would be considered hideous if you looked at the equivalent woman of that age (but an OK-looking guy for his age, imo). He's married to a beautiful model-looking woman in her 20s or early 30s. She's not only beautiful, but she's intelligent, accomplished, loving, and a great mother. WHEN will this stupid trope end? Yes, there is very occassionally a person in their 50s who marry someone that much younger, but is relatively rare. But in action, SF, and thriller movies, it seems it is the norm. And it is HARMFUL. Because of this, there are women who think that even if they find a responsible man who loves her, they get married, have children, she's loving, and responsible, and good at her job, but 99% of women in the US think that her husband will stop loving her once she reaches 32 and/or if she exceeds 120 pounds. STOP IT, FOR THE LOVE OF GOD. If you watch UK shows, they show men in their 40s and 50s and beyond falling in love with NORMAL-looking women their age. You're ruining people's lives with this trope.