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Liquid Water Space Rocket

Pop it in the Microwave
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Rockets are nasty big dangerous things 'cos they contain lots of explosive gases, flamable liquids or exotic powders. You also need an oxidant (unless you're runnning mono-propellant like hydogen-peroxide, which can explode if it gets a speck of dust in it).

My idea is to fill the tanks with regualar H20 at STP - in other words, liquid water. Turn this into a fine mist and pass over a very hot (lets say 1500K) grid and you seperate it out to Hydrogen and Oxygen. Recombine at your nozzle and you've got a conventional H2 - 02 rocket, without the enormous inventory of explosives.

Only problem....how do you keep the grid at 1500K? You'd have to send the energy up from the ground. One can imagine using Lasers or Microwaves for this, though I wouldn't want to trivialise the Engineering, hence the posting on Halfbakery not the US Patent Office.

Gyro, Jul 15 2004

thrivals link as a link http://www.rexresea...meyerhy/meyerhy.htm
no char... [po, Oct 21 2004]

Put-Put boat http://www.nmia.com...-pop/aapt/crane.htm
Also called a Pop-Pop or Toc-Toc [ldischler, Oct 21 2004]

[link]






       I think Thermolysis is the word you are looking for, and it occurs at approx 3000C, if I remember correctly.
The energy for your system comes from the ground. There is no other source. It won't work very well. Sorry -.
Ling, Jul 15 2004
  

       It definitely does sound like a whole lot of energy would be going into a system . . . that is designed to . . . make energy easier . . . to garner . . .   

       I thought you were just going to say "fill it with water, cork it, and at the appropriate time let the pressure differential take care of the rest." KER-BONE!
contracts, Jul 15 2004
  

       Preheated, Larry Niven "Footfall" and others.
normzone, Jul 15 2004
  

       The energy required wouldn't be significantly different to a regular H2 - O2 rocket (though conversion efficiencies might complicate this)   

       It turns a problem of explosives handling into a a problem of wireless energy transmission. Shall I just fishbone this myself?   

       Thanks for the feedback. Google tells me thermolysis of H20 occurs at temperatures above approx 2200K (2500 deg C give or take a summers day) so maybe I have a materials science problem too.
Gyro, Jul 16 2004
  

       nitpicking... 2200K = 1900C give or take a summers day...
david_scothern, Jul 16 2004
  

       [Gyro], it was a good, solid attempt. Ten points!
contracts, Jul 16 2004
  

       Forgive me for being pedantic, but isn't liquid water, just water? Frozen being ice; that above boiling-point being steam? The liquid bit just seems a tad redundant.
silverstormer, Jul 16 2004
  

       This is a great idea, albeit baked. (U need 2 scroll down aways;) see: http://www.rexresearch.com/meyerhy/meyerhy.htm   

       Much too good for the little ppl's cars. You must buy our oil instead.
thrival, Jul 16 2004
  

       That link shows a process whereby water is broken down to H2 and oxygen, then burnt to give water and energy. Perpetuum mobile. Whatever your personal beliefs on its possibility or otherwise, it's solidly rejected by the 1/2B.
david_scothern, Jul 16 2004
  

       How about a foot-operated pump the introduces compressed air into the water. When you've built up enough pressure, just pop the cork out of the bottom and stand back. I had a toy like this when I was a kid.
cranford, Jul 16 2004
  

       because it won't get you go-ing fast enough, [crandford].
my-nep, Jul 16 2004
  

       Maybe if the astronauts leaned forward...
RayfordSteele, Jul 17 2004
  

       Hmmm - next idea is an IE plugin that converts Kelvin to Centigrade.
Gyro, Jul 20 2004
  

       Not quite rocketry, the put-put boat used a water jet for propulsion. The neat thing was there were no moving parts. See link.
ldischler, Jul 20 2004
  

       "...how do you keep the grid at 1500K?"
Solar energy? Nuclear energy?
  

       I would be so much simpler to just boil the water off. At a low pressure, that shouldn't need too much heat.   

       But, since weight is such a premium in space-flight maybe this is a goer, despite the energy concerns.   

       [looks at thrival's link. Interesting.]
st3f, Jul 20 2004
  

       If you're going to be pumping that much energy in from a ground station, it's better just to go with vaporized aluminum or copper as your propellant. And that is at least pre-heated in many different trial projects.
MechE, Jan 25 2009
  

       I like the idea these are the basic components...
--- a rocket requires mass to accelerate
--- heat can be transfered at a distance
  

       ...
madness, Jan 26 2009
  

       //The liquid bit just seems a tad redundant.// Liquid aqueous melted ice.
MaxwellBuchanan, Jan 26 2009
  

       The beauty of this is that immediately after the water is seperated by the high heat into H2 and O2, the high heat makes them ignite and combine into water. Once established the cycle should allow for infinite propulsion.
bungston, Jan 26 2009
  

       As [bungston] amusingly pointed out, there is no reason to expect the reaction to reverse, unless you take the trouble to cool the reactants first - using water, perhaps. Seriously though, in the divergent part of the nozzle, where heat is being converted to velocity, the reaction would reverse, and the chemical energy released would contribute to thrust.
spidermother, Jan 27 2009
  
      
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