Journey to the Far Side of the Sun (1969) ending / spoiler
Ross is unable to dock with the shuttle and the controls of his ship do not respond. Ross' ship makes it back to Earth and unable to control the ship he crashes into the launch site. The crash erases all information about the doppelganger Earth. Years later, Jason Webb is at a nursing home and no one believes that there's another Earth. The final scene is Jason, in a wheelchair, going towards his own reflection in a mirror.
Submitted by Racer X