Destination Moon was a 1950 science fiction film, and one of the first hard science fiction movies, with only the 1929 German silent film Frau im Mond (Woman in the Moon) challenging it for the title of first serious space travel movie. It was produced by George Pal, directed by Irving Pichel, and stared John Archer, Warner Anderson, Tom Powers, and Dick Wesson.
Filmed in Technicolor, using the most modern filming techniques (including Puppetoons-based model rockets!), and with constant input from Robert A. Heinlein and a number of scientific experts, the movie, today, looks like crap. It is an excellent example of what film-makers in 1950 could do, but they really couldn't do much.
What they could do, and spent $592,000 doing well, was take a genre that was mostly based around finding and fighting monsters, and showed that it could be about science. Heinlein and his posse were obsessive about accuracy, to the point where the moon set is a painstakingly rendered recreation of Harpalus crater, with the Earth placed in the sky exactly as it would be if you were on the moon (Harpalus crater was selected not only so that the Earth would appear picturesquely just over the horizon, but also because it was in the northern latitude, and so the Earth would appear "right-side-up" as per the traditional classroom globe).
This level of scientific accuracy was attempted throughout. The rocket seat cushions were inflatable, and when the five Gs of acceleration hits during takeoff they were suddenly deflated as if crushed by the force; likewise, the actors had rubber make-up strips covering 'harnesses' over their faces; when the acceleration hit, their faces were stretched just as they would be during a real blast-off. A ridiculous amount of time and trouble was spent in making things float in zero-G; making the light on the moon harsh and one-directional, thus maintaining the lunar shadows; and making the rocket cockpit both realistic and filmable, resulting in a full scale cockpit on bi-directional gimbals, constructed so that each and every steel wall panel could be unbolted, allowing the camera to film the cockpit from any angle as needed.
This was intended to be an adventure film, but also an educational film. For many viewers, this would be their introduction to orbital mechanics, reaction mass, and perhaps even zero-G. One scene revolves around a crewman falling off the hull during repairs, and using an oxygen cylinder to propel himself back to the ship; this was a cunning solution, and as far as I can find, this first time this trick was depicted in the movies.
That said, it is worth emphasizing that all of this was done 11 years before the first human actually made it to space, and there were many uncertainties. Part of the research done for the film was trying to decide if stars would twinkle if seen in space; there were valid scientific theories either way. The surface of the moon was depicted as covered in desiccation cracks, as if the surface had been flooded and then dried; no one could say this wasn't accurate. Likewise, while the men floated realistically in space, they walked normally on the surface of the moon. Given the research and attention to detail in much of the film, this is jarring, but it was also being done 19 years before we'd actually get to the moon.
The movie business is cut-throat, and as the publicity for Destination Moon mounted, with nationwide radio ads, write-ups in most major publications, and public interest running high, Lippert Pictures zipped in with a competing film, Rocketship X-M. This was a cheap and quick film, with a $94,000 budget and filmed in just 18 days. The story also revolved around a moon-shot, but in this case the ship overshot the moon, and a few days later reached Mars, which was inhabited by humans that were apparently once very advanced, had a nuclear war, and now lived as cavemen. The film released 25 days before Destination Moon, and probably had only minimal impact on its profitability, and even less impact on the history of SF films.
Released on June 27, 1950, by January of 1952 Destination Moon was listed as the 88th top grossing film of 1950, with box office revenues of $1,300,000. However, it continued to remain a SF masterpiece for years, and has an estimated cumulative box office revenue of $5,000,000. For context, the run-away blockbuster hit that year was Samson and Delilah, with $11 million in revenues, with second place, Battleground coming in at $4,550,000.
The film was broadly based on Heinlein's 1947 novel Rocket Ship Galileo. However, after writing the screenplay, Heinlein then wrote a novella roughly based on the film to be used as part of the publicity blitz. This story was also entitled Destination Moon, and was published in Short Stories magazine. Rocket Ship Galileo was a fun book for kids; Destination Moon was a serious story for adults. At the time it was a good, solid piece of hard science fiction; today it's a bit boring. A large part of the story is taken up with the mechanics of spaceflight, which is now fairly familiar to most SF readers, and is also now quite dated. Likewise, the subplot of Communist saboteurs and the importance of getting an American military base on the moon did not age very well. This story has only been reprinted in Requiem, a collection of Heinlein's harder to find works published in 1992; it is not really worth the trouble of hunting down.