ROCKETSHIP X M 1950 (NAVARRE)

Early, but well made sci-fi about the first expidition to the moon which, after a mishap in flight turns out to be a trip to Mars. Once there the astronauts find a lost race of violent people who live like cavemen after an atomic war.
Great pulp sci-fi with John Emery as the leader of the expidition along with Lloyd Bridges, Hugh O'Brian, Noah Beery, Jr and Osa Massen. Morris Ankrum leads things back on earth. Good movie and good fun for sci-fi fans. Still holds up reasonably well today and far more entertaining than anything at the movies in the last 6 years.
One interesting side note, it is the leading lady who makes the fatal mistake at the end of the film. it's the only one I have ever seen that ends that way.