Space Platform by Murray Leinster

Nobody could have gone through the changes of emotion Joe had experienced that morning and remained quite matter-of-fact. Seeing a dead man who had more or less deliberately killed himself so that he wouldn't have to kill Joe -- for one -- had its effect. Knowing that it was certainly possible the man hadn't killed himself in time had another. Being checked over for radiation burns which would mean that he'd die quite comfortably within three or four days, and then learning that no burns existed, was something of an ordeal. And Sally -- of course her feelings shouldn't have been as vivid as his own, but the fact that she'd been scared for him held some significance. When, on top of all the rest, he went into the Space Platform for the first time, Joe was definitely keyed up.

But he talked technology. He examined the inner skin and its lining before going beyond the temporary entrance. The plating of the Platform was actually double. The outer layer was a meteor-bumper against which particles of cosmic dust would strike and explode without damage to the inner skin. They could even penetrate it without causing a leak of air. Inside the inner skin there was a layer of glass wool for heat insulation. Inside the glass wool was a layer of material serving exactly the function of the coating of a bulletproof gasoline tank. No meteor under a quarter-inch size could hope to make a puncture, even at the forty-five-mile-per-second speed that is the theoretical maximum for meteors. And if one did, the selfsealing stuff would stop the leak immediately. Joe could explain the protection of the metal skins. He did.