The Astronaut(1972)

An elaborate deception emerges when an American astronaut is lost on a mission to Mars. Space agency officials fearful of losing public support and government funding decide to cover up the accident by employing an exact double for the lost astronaut. The ruse begins to unravel when the wife of the lost astronaut realizes she is living with a different man. Although angered by the deception, the woman has fallen in love with the replacement and plans to keep the secret. They both have a change of heart and decide to reveal the secret when they discover a new Mars mission is underway.