"Wet" Asteroids Could Supply Space Gas Stations

FleaPlus writes "Water ice was recently discovered on the large asteroid 24 Themis, and Space.com discusses proposals for producing fuel from asteroid ice. NASA and the President recently announced plans for robotic precursor missions to asteroids (and a human mission by 2025), as well as a funding boost for R&D to develop techniques like in-situ resource utilization. Since most of the mass of a beyond-Earth mission is fuel, refueling in orbit would be a huge mass- and cost-saver for space exploration (especially if fuel can be produced in space), but a large unknown is how to effectively extract water in an environment lacking gravity."

Comments

One step at a time..

[pablo_max]

I mean hell, the morons in Washington can't even decide if we should build any kind of space ship.

Extracting is the least of your problems

[pedestrian crossing]

the water could be broken down into its component parts (hydrogen and oxygen) to make rocket fuel, experts say.

Gee, sounds simple. Except that rockets generally run on -liquid- oxygen.

You are going to need one hell of an infrastructure to manufacture/store LOX, even more so for liquid hydrogen.

Theory and practice are pretty far apart on this idea, to the point where I would call it impractical.

Re:Extracting is the least of your problems

[MattskEE]

Gee, sounds simple. Except that rockets generally run on -liquid- oxygen.
You are going to need one hell of an infrastructure to manufacture/store LOX, even more so for liquid hydrogen.
Theory and practice are pretty far apart on this idea, to the point where I would call it impractical.

To get good fuel density they will generally want liquid fuel. But getting it to liquid is just an engineering problem. Space of course is rather cold, but there is no air for convection transfer, and few solid bodies for conduction transfer. Which ordinarily leaves just radiation, which mainly takes a very large size to be effective, so it's hard to dispose of a lot of heat at once.

But the ship is parked on top of a frozen asteroid. If I were them I would might use the deep frozen water ice to cool the extracted gases to get them closer to liquid. It simultaneously melts the ice for processing. Two birds, one stone. Getting the extracted gases the rest of the way to liquid might be hard and inefficient. The speed will be limited by the size of the radiator and solar cells. I suspect they would send up a fuel processor in advance of a mission needing the fuel. The speed of processing needed is dictated by the mission lead time.

A 1 sentence analysis is no substitute for an actual study of the engineering problems and mission tradeoffs by qualified individuals. It seems a bit brash to discard an idea that may be a great boon to future manned and unmanned exploration of our solar system.

Re:yes but...

[HBI]

I've known far more than my share of Swedes and Finns, from my mudding days, and they always had excellent English, both written and in person. Yes, accented slightly but quite excellent.

Re:Mostly laughable concept.

[Tekfactory]

The Mylar solar mirror could be aimed at Titanium Oxide solar assisted electrolysis, making that process even more efficient.

Water would be prefiltered using existing NASA water filtering technology in use on the ISS now.

But what really strikes me about AH's answer is even with his engineering challenges which are overcomeable, and horrible energy to fuel ratio guesstimates.

This Rocket fuel assembled in space 24/7 in the asteroid belt would likely still be cheaper than if we created the fuel on Earth, and flew it out to the asteroid belt on a rocket.

It costs me $10,000 per kilo to get something to LEO, ususally assuming 80% of the rocket's mass is fuel the rest is the vehicle istself and payload, so we have at least 4 to 1 efficiency loss, probably more. It costs more to more to boost it to GEO, you use a transfer orbit, maybe even a solar sail to get to the belt but you're still burning fuel to stop and maneuver when you get there. How many kilos of fuel have I burned to get 1 kilo of fuel to my fuel depot in the asteroid belt?

ANY Explorer will have to learn to use indigenous resources at some point to stay in the field longer, or permanenetly. We cannot continue to rely on fuel made and shipped from Earth for any serious missions beyond our own orbit.

Re:Mining Asteroids like Eve Online

[aquila.solo]

That only applies to solo flying, what if it will be a formation flight?

I see what you did there.