How does a scuba diver’s oxygen tank last for ~1 hour but an astronaut’s lasts ~6-8 hours when both tanks are around the same size?

Question

How does a scuba diver’s oxygen tank last for ~1 hour but an astronaut’s lasts ~6-8 hours when both tanks are around the same size?

In: Technology

Answer 1

I haven’t seen a comment addressing the fact that astronaut suits usually supply an air pressure of 4.3PSIA. That a vacuum. Atmospheric pressure is 14.7PSIA or 0PSIG. The astronaut doesn’t need much pressure because the little osmosis that occurs in the lungs is enough from the oxygen concentration.