It's likely Rhea (the Saturnian moon), which technically has oxygen, but certainly not enough to breathe. Or prevent your bodily fluids from (literally) boiling off.
In any case, 'explosive decompression' (to the body) in a vacuum is a complete myth that is sadly widely perpetuated in fiction.
(It's just 1 atm of pressure difference. The human body can handle that, no problem. Structurally, that is. Asphyxiation, dehydration and freezing/overheating to death is another problem entirely.)
What gets you is the rapid transition between differing atmospheric pressures. Going from 1 atmosphere to 0 atmosphere is not that great a leap, but if your suit was pressurized with 10 atmospheres for some reason, then you'd be in trouble.
And it doesn't have to be space. When you think about it, the blast wave from an explosive device is really just compressed air hitting you very fast. And then before you know it, the blast wave is gone, and things quickly return to normal. You go from one extreme to another in less than a second, and your body is like a rubber band the whole time, being snapped back and forth.
What gets you is the rapid transition between differing atmospheric pressures. Going from 1 atmosphere to 0 atmosphere is not that great a leap, but if your suit was pressurized with 10 atmospheres for some reason, then you'd be in trouble.
Why on earth in space do you need 10 atms of pressure in a space suit? It's not like you're underwater where you need that much pressure to counteract ambient pressure (for breathing and, if necessary, to keep water out of a diving chamber). There's no benefit at all. Instead there's a significantly higher risk of the suit rupturing, and a bunch of side effects associated with breathing higher pressure gases that would require finicky gas mixes and reduced operating time/workloads to compensate. You'd also waste far more oxygen with the increased pressure.
IIRC current space suits are pressurized to ~0.3 atm because the respiratory gas mix is mostly oxygen (so the partial pressure of O2 in the suit is actually higher than on earth at sea level).
Why on earth in space do you need 10 atms of pressure in a space suit? It's not like you're underwater where you need that much pressure to counteract ambient pressure (for breathing and, if necessary, to keep water out of a diving chamber). There's no benefit at all. Instead there's a significantly higher risk of the suit rupturing, and a bunch of side effects associated with breathing higher pressure gases that would require finicky gas mixes and reduced operating time/workloads to compensate. You'd also waste far more oxygen with the increased pressure.
IIRC current space suits are pressurized to ~0.3 atm because the respiratory gas mix is mostly oxygen (so the partial pressure of O2 in the suit is actually higher than on earth at sea level).
Well, you're not wrong, but I was attempting to convey how explosive decompression works. One atmosphere's worth of difference isn't going to hurt you very much. Your body can withstand and otherwise adjust pretty quickly.
It's when you're sitting at around 10 atmospheres where rapid decompression causes people to turn inside out. You generally won't ever experience 10 atmospheres (without getting blown up by something), unless you are as you pointed out underwater, either in a vehicle, a habitat, or even a suit.
