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?
For Mars:
He and his team have discovered a more efficient way of creating methane-based rocket fuel theoretically on the surface of Mars, which can make the return trip all more feasible.
Houlin Xin headshot
“Lots of engineering and research is needed before this can be fully implemented. But the results are very promising,” says UC Irvine’s Houlin Xin.
Credit: UC Irvine
The novel discovery comes in the form of a single-atom zinc catalyst that will synthesize the current two-step process into a single-step reaction using a more compact and portable device.
“The zinc is fundamentally a great catalyst,” Xin says. “It has time, selectivity and portability — a big plus for space travel.”
The process of creating methane-based fuel has been theorized before, initially by Elon Musk and Space X. It utilized a solar infrastructure to generate electricity, resulting in the electrolysis of carbon dioxide, which, when mixed with water from the ice found on Mars, produces methane.
This process, known as the Sabatier process, is used on the International Space Station to produce breathable oxygen from water.
The ramjet rocket was cool.
I really like the possible HTP combinations. I think there is a pony in there.
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?
First sentence: I was actually agreeing with you.
For Mars: He and his team have discovered a more efficient way of creating methane-based rocket fuel theoretically on the surface of Mars, which can make the return trip all more feasible.
Houlin Xin headshot “Lots of engineering and research is needed before this can be fully implemented. But the results are very promising,” says UC Irvine’s Houlin Xin. Credit: UC Irvine The novel discovery comes in the form of a single-atom zinc catalyst that will synthesize the current two-step process into a single-step reaction using a more compact and portable device.
“The zinc is fundamentally a great catalyst,” Xin says. “It has time, selectivity and portability — a big plus for space travel.”
The process of creating methane-based fuel has been theorized before, initially by Elon Musk and Space X. It utilized a solar infrastructure to generate electricity, resulting in the electrolysis of carbon dioxide, which, when mixed with water from the ice found on Mars, produces methane.
This process, known as the Sabatier process, is used on the International Space Station to produce breathable oxygen from water.
The ramjet rocket was cool.
I really like the possible HTP combinations. I think there is a pony in there.