See How it will Happen in Your Lifetime! the bold teaser states . . . Conquest of Space, the 1955 movie produced by George Pal. The plot depicts a voyage to Mars, pulling from all science and technology of the day to be as realistic as possible.
As stated on Wikipedia, "Conquest of Space was based on The Conquest of Space, a non-fiction 1949 book illustrated by Chesley Bonestell and written by Willy Ley. Bonestell is noted for his photorealistic paintings of views from outer space, and worked on the space background art for the movie. The film also incorporated material from Wernher von Braun's 1952 book The Mars Project. The two books are straight popular science, with no story line.
The entire movie revolves around the struggle to endure the long trip, and the struggle to survive on Mars until a return to Earth was possible, with the underlying theme questioning whether mankind has the right to explore the heavens, or is he setting out as an invader to worlds not his own.
Directed by: Byron Haskin
Produced by: George Pal
Starring: Walter Brooke, Eric Fleming, Mickey Shaughnessy
Distributed by: Paramount Pictures
Release date: April 20, 1955 (U.S. release)