Conquest In Space is a future world concept from 1955 where we now have a World Space Organization where the USA is taking the lead in space exploration. An international space station is constructed and people live there months at a time. It’s under the command of General Walter Brooke who is concerned with the psychological problems of being too long in space. So he wants a handpicked crew for the exploration of the moon.
But the authorities on earth are shooting for bigger game. Kind of unrealistically they decide to forget the moon and aim for Mars. Brooke is in command and his eventual crew is his own son Captain Eric Fleming, Sgts. Mickey Shaughnessy, Benson Fong, and Phil Foster. In this future world no blacks or women are on the space station. The presence of the latter might well have cured at least some of the problems the guys were having.
On the way there Brooke develops some space problems of his own as he gets downright metaphysical, wondering if God meant for us to leave the planet earth that He bequeathed as a domain for man. Those issues cause all kinds of problems for the rest of the Mars expedition that are the basis for the plot of the film.
Conquest Of Space is imaginative but also intelligent. No hostile Mars creatures are found at least not in the corner of Mars they land. It was a realistic assessment of man surviving in a hostile environment and one of the better science fiction films of the Fifties.