Moon (2009)

Moon is proof that you don't need a big budget to make great science fiction. It's low budget, but very effective - essentially one actor, one lunar base, and a robot for company. He's coming to the end of a three-year stint mining the Moon for fuel, and (without giving anything away) things are not what they seem. The science is grounded and the base feels like a real, working place, not a movie set. It also has a lot to say about how a company might treat its workers when nobody is watching. Quiet, sad and clever.