Corrected entry: When Mars' two moons are shown in the scene after he eats the cooked sausages, they are both shown as spheres like our own moon, a "best guess" by the background painter. We now know from NASA photos that they are actually both jagged and irregular shaped moons.
Rlvlk
19th Nov 2007
Correction: Mariner 9 took the first close up shots of Mars' moons in 1971. The movie was made in 1964 using the best available data at the time; as such, this cannot be considered a mistake, unless you're seriously suggesting that they should have gone back, years later, and reshot the relevant scenes to take the new data into account.
Rlvlk