I'm designing an environment suit for humans to wear while interacting with a benevolent alien species while in alien space. Here's my question:
How much solid oxygen (by mass and volume) it would take to allow for six hours of comfortable, low-stress breathing by an average-sized human?
These are the constraints that I'm working with:
The suit the humans are using needs to be closed at a microscopic level, to prevent cross-contamination. While human and alien life relies on the same fundamental structures, due to an ancient artificial panspermia, contact happened recently enough that neither side has an effective immune booster to protect them from the other's microbiology. Therefore I want a closed-circuit system, like a rebreather, to prevent exhaled oxygen from contaminating the alien atmosphere.
The environment suits can maintain one atmosphere of pressure against the human wearing them. One of the constraints on scuba divers is that being under more pressure reduces the amount of time that their air supply can sustain them, so assume that the suits can negate the normal differences in pressure their wearers will be exposed to.
I see that the unit of measurement for the pressure δ-phase (orange) oxygen forms at is gigapascals, but the aliens have the ability to store and generate energy on vast scales and with vast precision. However, I'll be happy with answers using any of the stages.
An answer that results in an oxygen pack capable of going off like a bomb when breached would be preferred.
Also if there's an easier way to supply breathable atmosphere for long periods than just condensing oxygen more, given the assumption of cheap, bulk, energy, then please let me know.
That's my first question here on worldbuilding. If I've made any mistakes with form, or if something needs to be clarified, let me know.