Well, I was wondering, as the title of the thread says, What kind of atmosphere is in the cargo bay of the space shuttle during launch? There’s no reason to put breathable air in there, and the gases would just add extra weight. Is it pumped to a vacuum, or something?
Well, thanks for everyone’s time,
Ranchoth
I am guessing they would just vent the air as they went up or something. There is no point inputting undue stress on he cargo hold by evacuating it.
Yes, the cargo hold is vented to the outside. There’s no reason not to put breathable air. Using any other gas is dangerous for ground crews working in/around the cargo hold.
Pumping it out would require the doors and other structure to be stronger, therefore heavier, to take the pressure differential. That would certainly add more weight than removing the atmosphere.
Pumps aren’t necessary.
The cargo doors aent’t perfect hermetic seals, so air seeps out during the transition of launch to orbit, and back in during
re-entry.