I wonder if there's ever been done research into "hot" electrolysis? It wouldn't be too hard to have a superheated cell in space, since all you'd have to do is anodize it black and leave it in sunlight...
Mike Free > On Thu, 20 Feb 2003, Michael Wallis wrote: > > So they planned to launch water (likely on the shuttle) crack it in > > LEO and use it as fuel to get to the Moon? > > It was suggested. In particular, if you're flying a bunch of shuttle > flights (to the same orbit) which are volume-limited for some reason, > topping up the mass with something well-behaved like water could be > essentially free. This suggestion has come up repeatedly over the years; > the SEI-related study is just the one I happened to know about. > > They didn't *plan* to do this; they studied it briefly and concluded that > it was too much trouble to be useful. > > I think one reason why the idea keeps coming up is that people don't have > a clear idea of the energy costs of electrolysis. If you really could > make all the fuel for the mission a day or two before launch, you could > dodge some of the annoying problems of in-space LH2 storage. *That* might > perhaps make it worthwhile. But of course, you can't, so you have to deal > with the storage issues *anyway*. That being the case, if you must use > LH2, just shipping it up from the ground is simpler. > > > > ...So perhaps 35MJ/kg, or about 10kW-hr/kg, if we're lucky. > > > > I don't remember it being that hard in high school chem class, but > > that was 25+ years ago. Ok. It's hard to crack water. > > In bulk. It's easy enough to demonstrate electrolysis with a couple of > batteries, but the production rate of that demonstration is very low -- > you get gas measured in milliliters, which means you're cracking an amount > of water measured in milligrams. (Oxygen gas at room conditions is very > roughly a kilogram per cubic meter, i.e. a milligram per milliliter, and > that's most of the mass of the cracked water.) > > Henry Spencer > [EMAIL PROTECTED] > _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
