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#1
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an idea for your ridicule
Hi sci.space.tech
It seems that nuclear power is useless for booster applications and it has forever been religated to upperstages. Propellant temperature is constrained to what a solid core reactor can tolerate and this temperature is certainly not breakthrough. I can see how a material that could withstand temperatures above 5500 k would revolutionize rocket propulsion systems practically overnight.. Not going to happen, anytime soon, if ever. NTR is only interesting when using pure H2 as a propellant. H2 or better yet, just H, has the smallest molecular weight of all propellants. Power is ironically (to me) a reason why an NTR is impractical as a booster. Although it has better gas milage than a chemical rocket, it doesn't have the power push it's own gas. In other words, power to weight ratio is a big issue. Hows a few extra gigawatts sound? Sounds like a really heavy reactor! Chemical rocket efficency has theoretically peaked with the SSME. My question now boiled down is: Would preheating the H2, to break it down to H, before it enters the combustion chamber improve a chemical rocket's "gas milage"/exhast velocity? |
#2
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an idea for your ridicule
In article ,
aSkeptic wrote: Would preheating the H2, to break it down to H, before it enters the combustion chamber improve a chemical rocket's "gas milage"/exhast velocity? If you could do that... yes, very considerably. You could forget the oxidizer, and just let the H recombine to H2 -- an *IMMENSELY* energetic reaction, which would not only make most other chemical rockets obsolete, but would eliminate all interest in solid-core nuclear-thermal rockets. Nothing short of gas-core nuclear could compete. Trouble is, all that energy has to *come* from somewhere. As you might guess from the above, you need extremely high temperatures to break down H2 to H. This isn't some little add-on to the propulsion system; it *becomes* the propulsion system. Practical interest in such approaches centers on finding a way to stabilize H, so you can invest all that energy on the ground, and release it in flight without having to carry the powerplant along. Unfortunately, nobody has yet found any workable stabilizing technique. -- MOST launched 30 June; science observations running | Henry Spencer since Oct; first surprises seen; papers pending. | |
#3
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an idea for your ridicule
ractical interest in such approaches centers on finding a way to
stabilize H, so you can invest all that energy on the ground, and release it in flight without having to carry the powerplant along. Unfortunately, nobody has yet found any workable stabilizing technique. -- MOST launched 30 June; science observations running | Henry Spencer since Oct; first surprises seen; papers pending. | could you trap a solitary H atom inside something like a buckyball? take care Blll |
#4
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an idea for your ridicule
BllFs6 wrote:
could you trap a solitary H atom inside something like a buckyball? You might be able to, but... (1) the energy/mass now sucks, and (2) the buckyball+H is a molecular radical, and they will react with each other. Paul |
#6
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an idea for your ridicule
In article ,
BllFs6 wrote: ...centers on finding a way to stabilize H, so you can invest all that energy on the ground, and release it in flight without having to carry the powerplant along. Unfortunately, nobody has yet found any workable stabilizing technique. could you trap a solitary H atom inside something like a buckyball? Such approaches have been suggested -- although I'm not sure it was recent enough for buckyballs in particular to be mentioned -- but they wouldn't make very good rocket fuels, alas. The whole point of H is the enormous energy *per unit mass*; if it takes a buckyball (mass = 720) to contain each H (mass = 1), that just doesn't work out very well. -- MOST launched 30 June; science observations running | Henry Spencer since Oct; first surprises seen; papers pending. | |
#7
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an idea for your ridicule
Thanks for your insight, Henry.
I think what I proposed is way too severe. Making H2 into H H is impractical and fantastic. The silly idea I have is using something like NERVA to preheat one or both components of a chemical bipropellant. Dissociation would be interesting, but what I'm getting at is.. uh.. Ok heres annother wild example. Yes this is probably one of the dumbest/impractical ideas you'll find here.. The combustion temperature of the SSME is around 4000 K (if memory serves). Could a greater combustion temperature be achieved by heating both components (O2/H2) to say 2000 K before they are burned? Or would the burn still be close to 4000 K as they are now? (Henry Spencer) wrote in message ... In article , aSkeptic wrote: Would preheating the H2, to break it down to H, before it enters the combustion chamber improve a chemical rocket's "gas milage"/exhast velocity? If you could do that... yes, very considerably. You could forget the oxidizer, and just let the H recombine to H2 -- an *IMMENSELY* energetic reaction, which would not only make most other chemical rockets obsolete, but would eliminate all interest in solid-core nuclear-thermal rockets. Nothing short of gas-core nuclear could compete. Trouble is, all that energy has to *come* from somewhere. As you might guess from the above, you need extremely high temperatures to break down H2 to H. This isn't some little add-on to the propulsion system; it *becomes* the propulsion system. Practical interest in such approaches centers on finding a way to stabilize H, so you can invest all that energy on the ground, and release it in flight without having to carry the powerplant along. Unfortunately, nobody has yet found any workable stabilizing technique. |
#8
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an idea for your ridicule
Lets see now, carbon has an atomic weight of 12. We have 60 of them in a
buckyball, and it will be storing 1 hydrogen atom. That may work as far as stabilizing the H but Im not to sure it would be of any help in a propulsion system for use in space : ). Mike In article , (BllFs6) wrote: ractical interest in such approaches centers on finding a way to stabilize H, so you can invest all that energy on the ground, and release it in flight without having to carry the powerplant along. Unfortunately, nobody has yet found any workable stabilizing technique. -- MOST launched 30 June; science observations running | Henry Spencer since Oct; first surprises seen; papers pending. | could you trap a solitary H atom inside something like a buckyball? take care Blll |
#9
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an idea for your ridicule
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#10
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an idea for your ridicule
Magnetic confinment? Then again, the energy density of a plasma is probably
pretty low. Uzytkownik "Henry Spencer" napisal w wiadomosci ... In article , aSkeptic wrote: Would preheating the H2, to break it down to H, before it enters the combustion chamber improve a chemical rocket's "gas milage"/exhast velocity? If you could do that... yes, very considerably. You could forget the oxidizer, and just let the H recombine to H2 -- an *IMMENSELY* energetic reaction, which would not only make most other chemical rockets obsolete, but would eliminate all interest in solid-core nuclear-thermal rockets. Nothing short of gas-core nuclear could compete. Trouble is, all that energy has to *come* from somewhere. As you might guess from the above, you need extremely high temperatures to break down H2 to H. This isn't some little add-on to the propulsion system; it *becomes* the propulsion system. Practical interest in such approaches centers on finding a way to stabilize H, so you can invest all that energy on the ground, and release it in flight without having to carry the powerplant along. Unfortunately, nobody has yet found any workable stabilizing technique. -- MOST launched 30 June; science observations running | Henry Spencer since Oct; first surprises seen; papers pending. | |
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