1969/7: Doppelgänger aka Journey to the Far Side of the Sun 1969

 Trailer:

Watch movie:

https://archive.org/details/journey-to-the-far-side-of-the-sun-1969 

 https://en.wikipedia.org/wiki/Journey_to_the_Far_Side_of_the_Sun

https://www.moriareviews.com/sciencefiction/doppelganger-1969-journey-to-the-far-side-of-the-sun.htm 

https://fanderson.org.uk/productions/doppelganger-journey-to-the-far-side-of-the-sun/

https://sciencefictionruminations.com/2011/03/27/a-film-rumination-journey-to-the-far-side-of-the-sun-variant-title-doppelganger-robert-parrish-1969/