Rocketship X-M (1950, also known as Expedition Moon and originally as Rocketship Expedition Moon) is billed as “the first outer space adventure of the post-World War II era”.
It’ about a Moon expedition that, through a series of unforeseen events, instead travels to Mars. Once there, its crew discovers the remnants of a Martian civilization that was destroyed long ago by atomic war and has now reverted to barbarism.
It stars Lloyd Bridges, Osa Massen, John Emery, Noah Beery, Jr., Hugh O’Brian and Morris Ankrum. It was produced and directed by Kurt Neumann.