Didn't know about the finger joke, but had one turn handling a double-base (nitrocellulose-nitroglycerine) rocket propellant grain. Absolutely foul smell. We had to wear scuff pads on our shoe soles made of copper sponge, wired to contacts on our calfs, so we were always at ground potential to avoid static sparking. The handling room was equipped with blowout panels in case there was a light-off. Absent that, I calculated that the gas flow out the door would have been over 100 mph. Serious business.
What you describe for an idea was an invention disclosure that I came up with in the 1980s: using a small nuclear reactor to heat up propellants not to expel directly, but to amp up the effective specific impulse upon combustion. The problem was how to get Centaur-level performance out of a stage that could fit into the payload bay of the Space Shuttle. The hydrogen tank was the problem. Too big. And going pure nuclear wouldn't help because the required hydrogen tank was still too large. I was just looking at heating up (e.g.) hydrazine and nitrogen tetroxide to injection temperatures several hundred degrees hotter than normal. It looked like it could work, and it packaged fairly densely. Reactor power was about a tenth that of a pure nuke. I think I anticipated NASA's LANTR concept by about 7 years.
As for high Isp, both methane and ammonia have been considered as nuclear thermal engine propellants. The trick there is to heat them high enough to dissociate them into hydrogen and methylene (CH2) or nitrogen, arriving at a lower molecular weight. LANTR would have added oxygen in the nozzle for supersonic combustion. I think they may have been concerned about the reactivity of hot oxygen as well. If that splits into single oxygen atoms, they are terribly reactive. In Dr. Robert Bussard's text on nuclear rocket engines, he points out that one can gain a significant boost in Isp by running a nuclear thermal engine at max temperature and lower chamber pressure, so the hydrogen is dissociated into separate atoms.
When I was in my teens, I was convinced that a way to go was to create monatomic hydrogen and let it react by recombination. I recall the performance numbers were equivalent to a nuclear thermal rocket engine. Easy enough to make: just run hydrogen through an electric arc. Power supply? I speculated a compact nuclear -electric generator. So, the advantage? Separation of the reactor design problem from the direct thrust chamber environment, and no fallout problem from terrestrial operation. (I figured out the benefit later. At the time, it was just a cool idea.)
Great discussion. Great minds think alike. In college I proposed two types of propulsion. The first is similar with monatomic hydrogen, except that I accelerated protons to near the speed of light. Working to maximize the MV. The other one was a matter/anti-matter propulsion. I laid out the potential production from CERN, etc. It wasn’t very long before they started collecting antimatter.
You may be right. Another invention disclosure was my effort to arrive at a propulsion system that would enable interstellar travel on a culturally feasible timeframe. I took Alpha Centauri as a target distance and 100 years as a maximum feasible time that an organization could cohere and persist to receive data from an interstellar probe. Then it came down to estimating the Isp needed for a reaction propulsion system. Without going into what peyote dreams got me there, I arrived at the use of Birkeland Rays, streams of million-electron-volt electrons, using relativity to give them relativistic momentum far in excess of their subrelativistic levels. MeV electrons are fairly easily made. As a suitable propellant source for electrons, I selected lithium. Hydrogen and helium would be low-density cryogens, not good candidates for a long-duration mission. Lithium had 3 electrons to offer when fully ionized, and the positive nuclei could be dumped overboard in a conventional ion engine. The net result was an Isp of about a million seconds.
But, at the end, I realized the dismal problem of all high-Isp systems: the deadweight of the power supply system...as power scales with the square of the exhaust velocity. This is why satellite ion propulsion systems are not operated at the highest Isp they are capable of performing: the reduction in propellant mass is more than overcome by the increase in power system mass.
I am scared shitless about antimatter. No containment system can be perfect, and a containment failure would be catastrophic for anything beyond specimen level. I don't want to be around when bright young fellows think they can make it by the gram. It is for similar reasons that I have never been seduced by the use of liquid ozone as an oxidizer (though I will admit to wondering how far one can cheat). Great gain in performance...but it is likely to detonate if you look at it the wrong way. Or the right way. Equal opportunity group suicide complex.
O3 sounds like fun to me. If I were younger, I would ride that candle.
Imagine if we could stabilize triatomic hydrogen in liquid form and combine it stabilized O3 in liquid form. That would be wild.
For humans interplanetary travel, I was pondering a high mass flow rate from orbit for the initial speed jump, followed by an ion engine.
The nuke power is a weight challenge. I was working with some folks on a small nuclear power plant for a diesel submarine conversion for the Navy, especially the Seals. But Boeing snatched that and the funding dried up. The key was a thermal electric conversion of 30%. Double the best I could find before them.
Ion engine: Accelerating electrons is easier, but my idea was to accelerate protons for the mass advantage.
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.
Didn't know about the finger joke, but had one turn handling a double-base (nitrocellulose-nitroglycerine) rocket propellant grain. Absolutely foul smell. We had to wear scuff pads on our shoe soles made of copper sponge, wired to contacts on our calfs, so we were always at ground potential to avoid static sparking. The handling room was equipped with blowout panels in case there was a light-off. Absent that, I calculated that the gas flow out the door would have been over 100 mph. Serious business.
What you describe for an idea was an invention disclosure that I came up with in the 1980s: using a small nuclear reactor to heat up propellants not to expel directly, but to amp up the effective specific impulse upon combustion. The problem was how to get Centaur-level performance out of a stage that could fit into the payload bay of the Space Shuttle. The hydrogen tank was the problem. Too big. And going pure nuclear wouldn't help because the required hydrogen tank was still too large. I was just looking at heating up (e.g.) hydrazine and nitrogen tetroxide to injection temperatures several hundred degrees hotter than normal. It looked like it could work, and it packaged fairly densely. Reactor power was about a tenth that of a pure nuke. I think I anticipated NASA's LANTR concept by about 7 years.
As for high Isp, both methane and ammonia have been considered as nuclear thermal engine propellants. The trick there is to heat them high enough to dissociate them into hydrogen and methylene (CH2) or nitrogen, arriving at a lower molecular weight. LANTR would have added oxygen in the nozzle for supersonic combustion. I think they may have been concerned about the reactivity of hot oxygen as well. If that splits into single oxygen atoms, they are terribly reactive. In Dr. Robert Bussard's text on nuclear rocket engines, he points out that one can gain a significant boost in Isp by running a nuclear thermal engine at max temperature and lower chamber pressure, so the hydrogen is dissociated into separate atoms.
When I was in my teens, I was convinced that a way to go was to create monatomic hydrogen and let it react by recombination. I recall the performance numbers were equivalent to a nuclear thermal rocket engine. Easy enough to make: just run hydrogen through an electric arc. Power supply? I speculated a compact nuclear -electric generator. So, the advantage? Separation of the reactor design problem from the direct thrust chamber environment, and no fallout problem from terrestrial operation. (I figured out the benefit later. At the time, it was just a cool idea.)
Great discussion. Great minds think alike. In college I proposed two types of propulsion. The first is similar with monatomic hydrogen, except that I accelerated protons to near the speed of light. Working to maximize the MV. The other one was a matter/anti-matter propulsion. I laid out the potential production from CERN, etc. It wasn’t very long before they started collecting antimatter.
You may be right. Another invention disclosure was my effort to arrive at a propulsion system that would enable interstellar travel on a culturally feasible timeframe. I took Alpha Centauri as a target distance and 100 years as a maximum feasible time that an organization could cohere and persist to receive data from an interstellar probe. Then it came down to estimating the Isp needed for a reaction propulsion system. Without going into what peyote dreams got me there, I arrived at the use of Birkeland Rays, streams of million-electron-volt electrons, using relativity to give them relativistic momentum far in excess of their subrelativistic levels. MeV electrons are fairly easily made. As a suitable propellant source for electrons, I selected lithium. Hydrogen and helium would be low-density cryogens, not good candidates for a long-duration mission. Lithium had 3 electrons to offer when fully ionized, and the positive nuclei could be dumped overboard in a conventional ion engine. The net result was an Isp of about a million seconds.
But, at the end, I realized the dismal problem of all high-Isp systems: the deadweight of the power supply system...as power scales with the square of the exhaust velocity. This is why satellite ion propulsion systems are not operated at the highest Isp they are capable of performing: the reduction in propellant mass is more than overcome by the increase in power system mass.
I am scared shitless about antimatter. No containment system can be perfect, and a containment failure would be catastrophic for anything beyond specimen level. I don't want to be around when bright young fellows think they can make it by the gram. It is for similar reasons that I have never been seduced by the use of liquid ozone as an oxidizer (though I will admit to wondering how far one can cheat). Great gain in performance...but it is likely to detonate if you look at it the wrong way. Or the right way. Equal opportunity group suicide complex.
O3 sounds like fun to me. If I were younger, I would ride that candle.
Imagine if we could stabilize triatomic hydrogen in liquid form and combine it stabilized O3 in liquid form. That would be wild.
For humans interplanetary travel, I was pondering a high mass flow rate from orbit for the initial speed jump, followed by an ion engine.
The nuke power is a weight challenge. I was working with some folks on a small nuclear power plant for a diesel submarine conversion for the Navy, especially the Seals. But Boeing snatched that and the funding dried up. The key was a thermal electric conversion of 30%. Double the best I could find before them.
Ion engine: Accelerating electrons is easier, but my idea was to accelerate protons for the mass advantage.
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.