I have to ask...
...which crew member had to get married to a hairy alien in return for the oxygen generation unit?
The inhabitants of the International Space Station can breathe more easily this week, after a new oxygen generator was switched on. The new US-built machine will support the existing, but flaky, Russian Elektron generator, New Scientist reports. The new system was switched on on Wednesday, and by Thursday afternoon NASA said …
Does this mean that this generator could be used to fuel a Hydrogen car with just Water? It seems like that is the big issue involved; how to get Hydrogen stored safely up to the point it is burned.
Perhaps it takes more energy than it could produce in the engine? Or too big to fit into a car?
What Steve meant, by the way, is that it requires energy to run the Oxygen Generator, though as far as I can tell the Second Law doesn't come into it. The O2 generator probably has a theoretical limit to its efficiency, but I doubt that it is related to the amount of chemical energy stored in H2. Theoretically if the Generator was efficient enough it could use water as a sort of power amplifier - use a small battery to separate enough H2 to generate far more energy.
And that all is assuming that the Generator actually releases H2 as its O2 byproduct, which it doesn't necessarily have to do.
All in all, though, I suspect that NASA's gear is quite expensive and probably draws quite a lot of power for the amount of O2 it can process - humans require quite a bit less of that than a car would.