Doppelgänger (1969) more widely known as "Journey to the Far Side of the Sun"
The Wikipedia entry includes this in the plot summary:
...The shuttle detaches from Phoenix and loses contact with EUROSEC, falling through the atmosphere towards the Space Centre with Ross struggling to disengage automatic landing control. EUROSEC is unable to repair the fault from the ground, and Doppelganger crashes into a parked spacecraft. Ross is incinerated in the collision and a chain reaction obliterates the Space Centre, killing personnel and destroying all records of Ross's presence on the Counter-Earth.
Decades later, an embittered Jason Webb, long since dismissed from EUROSEC, has been admitted to a nursing home. In his dementia, the old man spies his reflection in a mirror mounted on a window. Rolling forwards in his wheelchair, and reaching out to touch his image, Webb dies when he crashes through the mirror.
