Just had this crazy idea...

[Sidoz11]

I was just watching Apollo 13 and when they mentioned the 'constellation urine' it kinda looked like rcs, so couldn't (in theory) an astronauts urine be used to power a spacecraft?

[Nuke]

urine is mostly water. you are better off reclaiming it for life support. but i suppose you could use it in a propellant for some kind of thermal engine.

[Acemcbean]

Theroretically, yes. In reality, DO IT FOR SCIENCE!

[TheDarkStar]

Just about anything can be used as RCS, as long as you can eject it from the ship.

[Bacterius]

"Okay guys, time for the burn."

"Oh, man, finally!" *unzips*

[KASASpace]

Perhaps you could take the water out (via distillation) and then use the remaining waste?

Quick Question: Isn't some ammonia in urine? Not a large amount, a very minute amount.

[Redrobin]

"Okay guys, time for the burn."

"Oh, man, finally!" *unzips*

ಠ_ಠ That can be very weird...

[Rokker]

Technically yes, to any extent that would make a difference, no.

[architeuthis]

It's ok, we're all a little crazy sometimes: witness a late 80's NASA plan to use a resistojet with electrolyzed waste water propellant for orbit keeping and attitude control for the future Space Station Freedom of the 1990's. Really low thrust, but the isp isn't half bad:)

Edited April 20, 2014 by architeuthis

[Rokker]

It's ok, we're all a little crazy sometimes: witness a late 80's NASA plan to use a resistojet with electrolyzed waste water propellant for orbit keeping and attitude control for the future Space Station Freedom of the 1990's. Really low thrust, but the isp isn't half bad:)

That isnt crazy, that is logical and possible. Straight up pissing out of the space craft is relatively crazy.

[Sidoz11]

What if it entered a machine like one of those jetwashers, which would make it high powered which would surely be even better

[kiwi1960]

No one here reads Sci-Fi?

I read a book once where this spaceship had an accident, all that was left was the cabin where some of the survivors were and a large container of water.... the passed close to a moon, turned the tap on, pointed a "phaser" at the water tank and got it to boil... the escaping liquid water gas moved them closer to the moon and they were rescued....

Any liquid could be used as an RCS with only one requirement.... that you could heat it up enough to make it expand so the escaping vapour would be under pressure... enough to actually move the space craft... there may not be any weight in space, but the space craft will still have mass.... if you stepped outside the capsule, and squirted water from a water pistol... well, it would be like pissing in the wind (pun intended) and nothing much would happen...

The other alternative to heating it would be to add something like caustic soda so you can make a gas.... but then you'd probably need a ton of caustic soda to make enough gas for any space mission....

The same problem with any other reactive substance ...

the best option would always be heat... you not only have the sun to provide that, but could generate power form solar panels to heat the water....

and urine would work just as well as water... except ET may not be too happy about it.