Capricorn One (1977)

In order to protect the reputation of the American space program, a team of scientists stages a phony Mars landing. Willingly participating in the deception are a trio of well-meaning astronauts, who become liabilities when their space capsule is reported lost on re-entry. Now, with the help of a crusading reporter, they must battle a sinister conspiracy that will stop at nothing to keep the truth.

Source: TMDb