Sorry, I mean humans can't breathe pure oxygen at atmospheric pressure. That's when it reaches toxic blood levels, because the lungs end up absorbing too much of it. Since breathing is based on CO2, you won't stop breathing just because you have too much O2, and you'll die.
The two examples you show operate at either below atmospheric pressure or in a situation where the extra oxygen is needed because of a deficiency in the person's ability to take in oxygen.
With the oxygen toxicity at too high pressures I agree. But you've got some weird understanding of the breathing reflex. Yes, breathing is based on CO2, in the sense that high concentrations of it
cause you to breathe. The way you describe it, it looks as if it were the other way around, that is low concentrations of CO2 caused you to breathe(or high concentrations caused you to cease breathing), which doesn't make sense.
I wouldn't rule out a chinese landing on the moon, but I severely doubt that they'd actually go to mars before the political will disappears.
But it could for example prompt the Americans to rejuvenate their own space program and send people to Mars themselves.
God I hope not. Mars has very little of value compared to the moon or asteroid capture. It's only good for politicians looking for filler to make speeches. Anybody else remember Bush's plan to go to Mars?
There's always the value of making people feel good about themselves. I've no idea what magnitude of an investment would going to Mars entail, but let's assume it'd be like 1% of the whole US budget for twenty years - incidentally it's the percentage of one's taxes that one can opt to give to a charity rather than the budget in this funny country I live in - and that the only tax revenue is the income tax(for the sake of clarity). I would happily agree to pay 1% extra in taxes to see people go to Mars in my lifetime, and perhaps have my kids grow up in a world where it happened. Hell, I'd perhaps even pay as much as 5% more, and know that I'm getting something fun and inspiring out of it, instead of e.g.some war in Asia.
Oh, and if I can have the Chinese or the Americans do it without my taxes, all the better!