Moon (2009)

Sam Bell is nearing the end of his three-year contract as the sole worker at a lunar station harvesting a new kind of fuel. His only companion is GERTY, an intelligent computer. Isolated and anxious to return home to his wife and daughter, Sam begins experiencing strange hallucinations. Following an accident, he discovers a doppelganger and starts to question his reality and the nature of his mission. The two Sams put together a plan to find the truth.