First of all, the only sci-fi part of the film is that the Space Shuttle program never ended. Second, as many other reviewers noticed, the movie starts really well, then it fizzles... it just fizzles. One can actually hear the feeble flatulent sound of the ideas in the movie going absolutely nowhere. The difference between the beginning and the ending is so vast that your mind is blown away and you go crazy, not unlike being in space for the first time.
It's a frightening window into what men see strong women as being: rigid, driven, single minded, egocentric, scary and ultimately going nuts whenever they need to chill and get the task done. It's Natalie Portman going crazy again on a difficult job, despite all the Southern cliches about no nonsense old nanas, toughing it out and working twice as hard as men to get to the same point and the mixed and meaningless metaphors uttered on a piano sound background. And why does she go crazy? Because of a man. Well, amongst other things that also happen because of men, like her marriage to a perfectly nice husband that does not look like Jon Hamm.
Bottom line: if you want a movie so deep that you will scour IMDb comments to understand what the hell happened, yet so superficial as to be 95% cliches, this is the thing for you. And no, Dan Stevens does NOT go crazy too and break the Universe. That's something else.