Have you read the book "Ignition" by John Clark? It is a broad history of propellant behavior and lore from the Naval Air Rocket Test Station (NARTS) days. He deals with all the strange actors. Ozone was nothing to kid about. The only stable deal I read about was to mix it as a minor solute with oxygen difluoride. The raw stuff was just too touchy. Worse than nitroglycerine. (It will mix with liquid oxygen, stable at a low percentage. But the problem is that oxygen has a lower boiling point and will boil off faster. If the concentration rises above 30%, the mixture will stratify into ozone-poor and ozone-rich [90%] layers, and the high-ozone layer is unstable.)
Your interplanetary thrust / Isp split sounds reasonable. I'm more inclined toward nuclear thermal rocket propulsion. I'm fascinated with nuclear fission rockets, where the nuclear reactions are mingled with the propellant: much higher operational temperatures and specific impulse (about 4000 seconds), but problems with loss of unreacted fissionables. I diagnose the problem as there being too high a loading of fissionables in the thrust chamber, in order to maintain a critical mass. I think the critical neutron flux should be supplied mainly by a solid annular reactor, and only the consumable fissionable mass added to the propellant...but I hadn't gotten a Ph.D. in nuclear engineering. (That's retrospect. Part of not knowing what I needed to do in earlier life.) Sigh. But who knows what terrible mistakes my alternate life could have made? Not nice to second-guess God's plan.
Was Boeing interested in submarines at that point? Or did they just acquire the money? At one point in the 80s, Boeing was working on an oxygen-aluminum electric cell that worked on the oxygen dissolved in seawater, for submerged drone application (miniature unmanned submarine). The Navy never took it up...that I ever heard of. But 30% nuclear powerplant conversion efficiency is pretty good, considering most commercial nuke powerplants are maybe at 40%, and they are fine-tuned.
The trick to my Relativistic Electron Beam Engine Concept (REBEC) was obtaining a high momentum from an initial rest mass. To do the same trick with protons would require them to be accelerated to an energy of about 2 GeV. Difficult to do with massive equipment.
Not that. I hadn't been aware of it, but it seems a clever approach. Robert Zubrin is actually full of clever approaches.
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I got my inspiration from an approach that was briefed to us from Los Alamos, for interceptor propulsion. The interceptor would have a container of uranium-235 hexafluoride gas, and would be inserted into a small nuclear reactor which would pulse it with neutrons, starting a chain reaction in the UF6. The gas would heat up semi-instantly and be expelled out of a nozzle like a bottle rocket. And off it would go.
I like it!! I spent a little time with the Los Alamos folks on a couple of occasions.
Once, I was trying to put together something. At Wright Patterson they had one piece. But they said the other piece: No way, no how, defies the laws of physics. I went down to Los Alamos and they had the other piece sitting on a shelf gathering dust. But they said the other piece: No way, no how, defies the laws of physics. I said: Do you guys ever talk to each other???
They had another bright idea that was so "unspeakable" we couldn't mention it in our analysis, except through a euphemism. It did, however, give me an idea for a solid-propellant nuclear rocket concept. (It dawned on me that all nuclear rockets under consideration were single-use systems, so why not embrace the idea?)
I had a brush with Lawrence Livermore National Laboratory (which I always referred to as "Lawrence Liverwurst" just because it was clever) during industry consultations on the Brilliant Pebbles idea. (Actually, dating from the former DARPA Project Defender's BAllistic Missile Boost Intercept, BAMBI, concept.) We had Lowell Wood drop in on the discussion. Wood was supposedly Edward Teller's protege'. High security. "Airlock" entrance.
Interesting. I like NTP to get things moving, then switching to Ion. NTP is usually liquid hydrogen, but I was thinking about liquid water. I haven’t sorted out the proton acceleration challenge. But, as I always told people who said it was too hard or impossible: You just need to be more creative. Guaranteed discussion win and it is true. This is fun. I haven’t gotten into the weeds in a long time. Add this to your pondering: A train like ship where the propellant “cars” are launched into orbit and attached to the crewed spacecraft with the propulsion system.
I never got around to a PHD. I helped my friend get his. Gave him my organizational leadership methodology that worked for small teams to the largest organization. I usually fixed the problems the PHDs didn’t know they had.
You would be better off with ammonia. If you heated water to dissociation, the average molecular weight would be 12 compared to hydrogen at 2. If a hydrogen engine were to get 1000 sec Isp (round number), the steam engine would get ~408 sec. No better than chemical propulsion. If you heated ammonia to dissociation, the average molecular weight would be 8.5, and the nuclear engine would get ~485 sec, a slight improvement. The number of hydrogen molecules is crucial. One might suppose that methane would be better yet, but the problem is that it might dissociate to methylene (CH2) and hydrogen. I don't know if CH is willing to be a standalone molecule. And you can't run a reactor hot enough to vaporize pure carbon. This all focuses on the huge penalty for a long trip of trying to store liquid hydrogen, for whatever purpose.
When I was in university, I had the three degrees behind me and the only place left was a Ph.D.---which was regarded as an academic path---or to get out into industry. Industry was where I wanted to go, and I did...and met plenty of Ph.D.s! But I got along with them just fine and did good work. One of my inspirations about this was a grad school professor who ran a department research lab. He had never finished his Ph.D. on account of contracting polio. But it didn't stop him from doing the work! He generally had a brilliant idea on a weekly basis.
The hydrogen accelerates easier, but somehow I was looking to increase the M with decreasing the V too much. More thinking required. But hydrogen for now. They seemed to be pretty locked in on Methane. Just had a question from a friend on how best to get methane on Mars. Turns out that a couple of my friends have links to Duffy. I gave him the UofC idea as the best option so far.
Airlock. Been there.
I like the latest in air breathing, solid fuel, throttleable missiles. Something to ponder for space. Solid fuel and liquid oxidizer. Some thought has been done on this. Had an interesting thought, but probably more likely to go big, bada, boom.
I think I've lost the thread of your meaning. Are you thinking back to a relativistic hydrogen ion? Easier than what? It is over 1800 times more massive than an electron, so it won't be easier to accelerate. If you mean hydrogen for a nuclear thermal rocket, it's all about the molecular weight of the working fluid: lower means higher velocity, given a fixed temperature. Reactors can operate only within the temperature capability of the reactor components. Robert Bussard pointed out that, even within that limit, you can squeeze more performance out by lowering the chamber pressure, allowing the hydrogen to dissociate, dropping the molecular weight to 1, thereby increasing Isp by 40%.
The scheme for methane on Mars is (1) find water from occult Martian ice, (2) get carbon dioxide from compression and separation of the Martian atmosphere, then (3) use a thermochemical process to go CO2 + 2 H2O => CH4 + 2 O2. So, you get a stoichiometric mixture of methane and oxygen, which would need to be purified and liquified. This needs a power source, of course, probably a nuclear reactor. Good luck with solar cells. I'm not comfortable with it. Too many ways for it not to work just right, and not working just right being a stoplight. (The Russians had a different approach. Just burn magnesium with CO2 and go. This is why I like the Russians.)
When I started at Boeing, we were working rocket-ramjet missile designs. It was a solid-fuel ramjet with an annular fuel grain that had a solid rocket propellant grain cast down the middle, and an extra nozzle with a higher expansion ratio (narrower throat) than the ramjet nozzle. The rocket would light off and accelerate the missile to ramjet cruise speed, burn out, eject the rocket nozzle out of the ramjet nozzle, and the ramjet would light off from the rocket propellant residual combustion. Then the missile would go into a steep climb, reaching an altitude of very little air. The ramjet would blow out from lack of sufficient oxygen and the missile would conduct a ballistic trajectory. On re-entry, the air stagnation temperature would re-ignite the ramjet fuel and it would proceed to target. We were proposing that for the never-pursued ASALM missile.
During the SDI years, I had interactions with the guys at Atlantic Research. They were working on high performance hybrid rockets, typically a metal hydride in a binder and hydrogen peroxide as the oxidizer (exothermic source of oxygen and water for a working fluid). With beryllium hydride and HTP, it could realize 450-500 seconds Isp, non-cryogenic, and high density. Other combinations were for kinetic kill vehicles. The Air Force laboratories were separated into liquid and solid branches, but no one wanted to "own" hybrids, so they were ignored. The path not traveled. I later spent a lot of time looking at burning metals with HTP, or carbon-based fuels that had triple bonds to jack up the combustion heat. My current fave is dicyanoacetylene, C4N2, with 3 triple bonds. Or other hydrocarbons with cyano groups. One can imagine some ferocious compounds. But how to make them?
Have you read the book "Ignition" by John Clark? It is a broad history of propellant behavior and lore from the Naval Air Rocket Test Station (NARTS) days. He deals with all the strange actors. Ozone was nothing to kid about. The only stable deal I read about was to mix it as a minor solute with oxygen difluoride. The raw stuff was just too touchy. Worse than nitroglycerine. (It will mix with liquid oxygen, stable at a low percentage. But the problem is that oxygen has a lower boiling point and will boil off faster. If the concentration rises above 30%, the mixture will stratify into ozone-poor and ozone-rich [90%] layers, and the high-ozone layer is unstable.)
Your interplanetary thrust / Isp split sounds reasonable. I'm more inclined toward nuclear thermal rocket propulsion. I'm fascinated with nuclear fission rockets, where the nuclear reactions are mingled with the propellant: much higher operational temperatures and specific impulse (about 4000 seconds), but problems with loss of unreacted fissionables. I diagnose the problem as there being too high a loading of fissionables in the thrust chamber, in order to maintain a critical mass. I think the critical neutron flux should be supplied mainly by a solid annular reactor, and only the consumable fissionable mass added to the propellant...but I hadn't gotten a Ph.D. in nuclear engineering. (That's retrospect. Part of not knowing what I needed to do in earlier life.) Sigh. But who knows what terrible mistakes my alternate life could have made? Not nice to second-guess God's plan.
Was Boeing interested in submarines at that point? Or did they just acquire the money? At one point in the 80s, Boeing was working on an oxygen-aluminum electric cell that worked on the oxygen dissolved in seawater, for submerged drone application (miniature unmanned submarine). The Navy never took it up...that I ever heard of. But 30% nuclear powerplant conversion efficiency is pretty good, considering most commercial nuke powerplants are maybe at 40%, and they are fine-tuned.
The trick to my Relativistic Electron Beam Engine Concept (REBEC) was obtaining a high momentum from an initial rest mass. To do the same trick with protons would require them to be accelerated to an energy of about 2 GeV. Difficult to do with massive equipment.
Were you referring to an NSWR propulsion system? Interesting.
Not that. I hadn't been aware of it, but it seems a clever approach. Robert Zubrin is actually full of clever approaches.
| I got my inspiration from an approach that was briefed to us from Los Alamos, for interceptor propulsion. The interceptor would have a container of uranium-235 hexafluoride gas, and would be inserted into a small nuclear reactor which would pulse it with neutrons, starting a chain reaction in the UF6. The gas would heat up semi-instantly and be expelled out of a nozzle like a bottle rocket. And off it would go.
I like it!! I spent a little time with the Los Alamos folks on a couple of occasions.
Once, I was trying to put together something. At Wright Patterson they had one piece. But they said the other piece: No way, no how, defies the laws of physics. I went down to Los Alamos and they had the other piece sitting on a shelf gathering dust. But they said the other piece: No way, no how, defies the laws of physics. I said: Do you guys ever talk to each other???
They had another bright idea that was so "unspeakable" we couldn't mention it in our analysis, except through a euphemism. It did, however, give me an idea for a solid-propellant nuclear rocket concept. (It dawned on me that all nuclear rockets under consideration were single-use systems, so why not embrace the idea?)
I had a brush with Lawrence Livermore National Laboratory (which I always referred to as "Lawrence Liverwurst" just because it was clever) during industry consultations on the Brilliant Pebbles idea. (Actually, dating from the former DARPA Project Defender's BAllistic Missile Boost Intercept, BAMBI, concept.) We had Lowell Wood drop in on the discussion. Wood was supposedly Edward Teller's protege'. High security. "Airlock" entrance.
Interesting. I like NTP to get things moving, then switching to Ion. NTP is usually liquid hydrogen, but I was thinking about liquid water. I haven’t sorted out the proton acceleration challenge. But, as I always told people who said it was too hard or impossible: You just need to be more creative. Guaranteed discussion win and it is true. This is fun. I haven’t gotten into the weeds in a long time. Add this to your pondering: A train like ship where the propellant “cars” are launched into orbit and attached to the crewed spacecraft with the propulsion system.
I never got around to a PHD. I helped my friend get his. Gave him my organizational leadership methodology that worked for small teams to the largest organization. I usually fixed the problems the PHDs didn’t know they had.
You would be better off with ammonia. If you heated water to dissociation, the average molecular weight would be 12 compared to hydrogen at 2. If a hydrogen engine were to get 1000 sec Isp (round number), the steam engine would get ~408 sec. No better than chemical propulsion. If you heated ammonia to dissociation, the average molecular weight would be 8.5, and the nuclear engine would get ~485 sec, a slight improvement. The number of hydrogen molecules is crucial. One might suppose that methane would be better yet, but the problem is that it might dissociate to methylene (CH2) and hydrogen. I don't know if CH is willing to be a standalone molecule. And you can't run a reactor hot enough to vaporize pure carbon. This all focuses on the huge penalty for a long trip of trying to store liquid hydrogen, for whatever purpose.
When I was in university, I had the three degrees behind me and the only place left was a Ph.D.---which was regarded as an academic path---or to get out into industry. Industry was where I wanted to go, and I did...and met plenty of Ph.D.s! But I got along with them just fine and did good work. One of my inspirations about this was a grad school professor who ran a department research lab. He had never finished his Ph.D. on account of contracting polio. But it didn't stop him from doing the work! He generally had a brilliant idea on a weekly basis.
The hydrogen accelerates easier, but somehow I was looking to increase the M with decreasing the V too much. More thinking required. But hydrogen for now. They seemed to be pretty locked in on Methane. Just had a question from a friend on how best to get methane on Mars. Turns out that a couple of my friends have links to Duffy. I gave him the UofC idea as the best option so far.
Airlock. Been there.
I like the latest in air breathing, solid fuel, throttleable missiles. Something to ponder for space. Solid fuel and liquid oxidizer. Some thought has been done on this. Had an interesting thought, but probably more likely to go big, bada, boom.
I think I've lost the thread of your meaning. Are you thinking back to a relativistic hydrogen ion? Easier than what? It is over 1800 times more massive than an electron, so it won't be easier to accelerate. If you mean hydrogen for a nuclear thermal rocket, it's all about the molecular weight of the working fluid: lower means higher velocity, given a fixed temperature. Reactors can operate only within the temperature capability of the reactor components. Robert Bussard pointed out that, even within that limit, you can squeeze more performance out by lowering the chamber pressure, allowing the hydrogen to dissociate, dropping the molecular weight to 1, thereby increasing Isp by 40%.
The scheme for methane on Mars is (1) find water from occult Martian ice, (2) get carbon dioxide from compression and separation of the Martian atmosphere, then (3) use a thermochemical process to go CO2 + 2 H2O => CH4 + 2 O2. So, you get a stoichiometric mixture of methane and oxygen, which would need to be purified and liquified. This needs a power source, of course, probably a nuclear reactor. Good luck with solar cells. I'm not comfortable with it. Too many ways for it not to work just right, and not working just right being a stoplight. (The Russians had a different approach. Just burn magnesium with CO2 and go. This is why I like the Russians.)
When I started at Boeing, we were working rocket-ramjet missile designs. It was a solid-fuel ramjet with an annular fuel grain that had a solid rocket propellant grain cast down the middle, and an extra nozzle with a higher expansion ratio (narrower throat) than the ramjet nozzle. The rocket would light off and accelerate the missile to ramjet cruise speed, burn out, eject the rocket nozzle out of the ramjet nozzle, and the ramjet would light off from the rocket propellant residual combustion. Then the missile would go into a steep climb, reaching an altitude of very little air. The ramjet would blow out from lack of sufficient oxygen and the missile would conduct a ballistic trajectory. On re-entry, the air stagnation temperature would re-ignite the ramjet fuel and it would proceed to target. We were proposing that for the never-pursued ASALM missile.
During the SDI years, I had interactions with the guys at Atlantic Research. They were working on high performance hybrid rockets, typically a metal hydride in a binder and hydrogen peroxide as the oxidizer (exothermic source of oxygen and water for a working fluid). With beryllium hydride and HTP, it could realize 450-500 seconds Isp, non-cryogenic, and high density. Other combinations were for kinetic kill vehicles. The Air Force laboratories were separated into liquid and solid branches, but no one wanted to "own" hybrids, so they were ignored. The path not traveled. I later spent a lot of time looking at burning metals with HTP, or carbon-based fuels that had triple bonds to jack up the combustion heat. My current fave is dicyanoacetylene, C4N2, with 3 triple bonds. Or other hydrocarbons with cyano groups. One can imagine some ferocious compounds. But how to make them?