Help me think of this movie title

[broganreynik]

I can't think of this movie for anything. I've even went back 2 years on movies I've reviewed and nothing rang a bell. Anyway, it's a sci-fi movie, in the vein of Event Horizon or Alien. It takes place on a spacecraft and towards the end, one of the characters ends up being a machine/robot, and its only objective is to make sure the mission succeeds, even at the cost of the crew. I know that's pretty basic, but that's all I can remember.