If they don't know how to protect a rocket, then how...?
SPOILERS
The whole purpose of this frankly dopey mission is to capture a meteor intact and bring it back to Earth so they can discover what it is about its make-up that enables it to stand up against cosmic rays...which, it's said, cause objects in outer space to disintegrate. (It's claimed this is happening to the Moon, though it's never stated why the Earth would be exempt from this effect.) Anyway, finding this out, we're told, will enable us to launch rockets so that they can safely travel through space and return to Earth.
Okay, forget for the moment that cosmic rays do not cause objects to disintegrate -- in or out of space. As has been noted, cosmic rays are passing through you as you're reading this, and you aren't disintegrating. (Presumably.) The entire "scientific" premise of this film is completely false.
But by the movie's own internal "logic", how can they send men up in rockets to discover a way to safely bring the rockets back, when the point of their going in the first place is to find out how to return in one piece? The rocket they brought down at the start of the picture explodes into pieces and the steel it was made of shatters when given a slight hit. Why wouldn't this happen to the manned rockets? That little tidbit is never explained. (The men are also shown film -- actual film -- of two mice who survived a trip into space. Forget the manned rockets. How come the moused rocket didn't disintegrate?)
A slight catch-22, or maybe a practical joke the men find out about once they're aloft?