New Molecule Could Lead To Better Rocket Fuel 121
MithrandirAgain writes "Trinitramid is the name of the new molecule that may be a component in future rocket fuel. This fuel could be 20 to 30 percent more efficient in comparison with the best rocket fuels available today, according to researchers (abstract). The discovery was made at the Royal Institute of Technology (KTH) in Sweden. 'A rule of thumb is that for every ten-percent increase in efficiency for rocket fuel, the payload of the rocket can double. What's more, the molecule consists only of nitrogen and oxygen, which would make the rocket fuel environmentally friendly. This is more than can be said of today's solid rocket fuels, which entail the emission of the equivalent of 550 tons of concentrated hydrochloric acid for each launch of the space shuttle,' says Tore Brinck, professor of physical chemistry at KTH."
Premature Celebration (Score:5, Informative)
From TFA:
"It remains to be seen how stable the molecule is in a solid form," says Tore Brinck.
And until then, this is a premature press release to be criticising the shape shuttle solid rockets.
Someone must need to re-up on their grant.
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Yes, I would have to agree that they're jumping the boat a tad. A long ways to go to fill up a rocket.
But the name is way cool. Kudos to the marketing team!
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Most modern solid-fuel rockets use pretty much the same fuel as the shuttle SRBs. It's cheap, stable and reliable but it does produce a lot of goop and the ISP could be better. If this stuff is stable it might make an excellent replacement for ammonium perchlorate oxidizer.
Shuttle SRBs are neither cheap nor reliable (Score:5, Interesting)
Most modern solid-fuel rockets use pretty much the same fuel as the shuttle SRBs. It's cheap, stable and reliable but it does produce a lot of goop and the ISP could be better. If this stuff is stable it might make an excellent replacement for ammonium perchlorate oxidizer.
Shuttle SRBs are more expensive and less reliable than equivalent liquid boosters. This is the main reason why SpaceX is only using liquid engines in the Falcon-9. ULA uses solid boosters for extra thrust on the Atlas V, but these solids are cheaper and more reliable than Shuttle SRBs. In addition, based on recent conference papers, I think they want to get away from solids in their next generation of rockets.
So why is NASA planning on using boosters based on the lower performing, more expensive, and less reliable Shuttle SRBs in their new Heavy lift rocket? This is because the Utah Congressional delegation is lobbying heavily for the company that makes the SRBs. The Utah senators inserted text into the continuing resolution that NASA is currently operating under that they claim prevents NASA from even doing trade studies to consider any alternatives to using the Shuttle SRBs.
Solids might have made sense in the 60s, but with current technology they are no longer needed except in a few specialized applications for robotic planetary exploration spacecraft.
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It is not so much building a stockpile as it is keeping the manufacturing infrastructure in place to minimize disruption if they need new SRBs manufactured on relatively short notice. For the same reason they continuously build aircraft carriers and submarines instead of doing a big batch and then stopping. If they stopped, the delay in restarting production would be significant.
It is not enough to have the design and manufacturing plans. You need the workers and specialized infrastructure as well.
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Now at this point you might speculate that the SRB's are esential to
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Hey now, don't forget the Saturn V rocket either. That mother could haul some mail. With an awesome service record to boot.
Re:Hydrochloric acid? (Score:4, Informative)
in small words the shuttle has 2 systems pushing it into orbit
1 the huge tank thing and the jets on the tail of the shuttle
2 those skinny rockets on either side of the huge tank thing
the huge one is hydrogen/oxygen the others are a solid rocket booster (btw thats where the name SRB comes from)
the SRB is just like a model rocket only bigger LOTS BIGGER and this is the fuel being replaced
(note for actual rocket scientists this is the post-it(tm) version so the details are a bit fuzzy)
Re:Hydrochloric acid? (Score:4, Insightful)
In even smaller words: Nothing you said addresses the parent posts questions.
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In even smaller words: Nothing you said addresses the parent posts questions.
C'mon, the answer is there, hard to miss. It's not like it's rocket science!
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Re:Hydrochloric acid? (Score:5, Informative)
This is a potential replacement for the fuel used in the solid rocket boosters, not the main engines.
While the main engine burn LH2 and LOX, emitting nothing but steam, the SRBs burn a rubbery mix of ammonium perchlorate, powdered aluminum and a polymer binder. They emit a pretty nasty exhaust stream, containing hydrogen chloride and aluminum oxide, among many other compounds.
Re:Hydrochloric acid? (Score:4, Informative)
LH2/LOX engines will perform better than this new compound no matter what. The only way to get better performance than LH2/LOX (for a chemical rocket) is to change the oxidizer.... maybe liquid ozone... or Fluorine. Fluorine is the best oxidizer you can get. Problem is that it tends to oxidize its container and then oxidize you.... nasty, nasty stuff.
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No doubt that these improved solid rockets would still be inferior to LH2/LOX liquids, but still a significant improvement to current solid rocket technology. Solids have the advantage of storability and simplicity of construction/low cost. They will continue to have wide application for the foreseeable future.
If you are interested in reading some stories about really exotic fuels/oxidizers, check out the book "Ignition!" by John D. Clark. Chlorine Trifluoride, anyone?
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Chlorine Trifluoride, anyone?
Chlorine trifluoride [wikipedia.org] is the worst chemical I have ever heard of. Does anybody know something more corrosive and hazardous?
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Can anyone explain this? I thought the space shuttle lifted off on hydrogen and oxygen. If the fuel is hydrogen and oxygen, the hydrochloric acid doesn't come from the fuel. What am I missing here? How would replacing hydrogen and oxygen with a new fuel that contains a new molecule be more environmentally friendly? How do we know that the properties of this molecule and the exhaust caused by it don't cause more environmental trouble than the exhaust of hydrogen and oxygen? Has anyone tested it?
Two Solid Rocket Boosters (SRBs) help get the shuttle off the pad (and a joint failure in one of these destroyed the Challenger, killing seven astronauts). The SRBs burn synthetic rubber as fuel and ammonium perchlorate is the oxidizer. When ammonium perchlorate burns the chlorine emerges as HCl.
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20-30% more efficient solid rocket fuel (Score:5, Informative)
The key part being "solid". Solid rocket fuels are notoriously inefficient compared to liquid fuels.
From the sounds of this stuff, assuming that 20-30% is closer to 30% than to 20%, we're talking roughly 75% as efficient as Hydrogen, and somewhat less efficient still than kerosene...
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> Solid rocket fuels are notoriously inefficient compared to liquid fuels.
They are also notoriously simple and inexpensive.
Re:20-30% more efficient solid rocket fuel (Score:4, Informative)
They are also notoriously simple and inexpensive.
The LOX/LH2 in the shuttle's external tank costs far less than the two SRBs on the side. It's the liquid-fuelled engines that are expensive, if you throw them away after each flight.
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So far, recycling equipment has been a fool's errand.
The great experiment in reusable space craft turned out to be a massive money hole, holding back space exploration to a large extent.
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The great experiment in reusable space craft turned out to be a massive money hole
Oh? Has anyone actually tried that experiment yet?
And no, Shuttle doesn't count: the external tanks are thrown away, the SRB's are more crash'n'salvage than reusable (take a look at what actually gets reused), and the Orbiter undergoes a major overhaul after every mission.
There have been experimental prototypes of reusable vehicles. DC-X for example, which demonstrated successful intact launch-abort capability as well as ra
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I think that was exactly the parents point. Shuttle was initially sold as reusable platform that will be oh so cheap once you'll average the initial cost over the projected lifetime.
Didn't turn out that way.
New molecule? (Score:5, Funny)
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Probably. But so far we couldn't find that past component of it, maybe in the future we will.
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Since we have over 150,000 years experience with tylium, the human race doesn't need that thiotimoline crap.
Solid rockets (Score:2)
Are best confined to July 4th and November 5th.
The big drawback is that once they're lit you have no control, you can't turn them off, or even throttle them down.
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The big drawback is that once they're lit you have no control, you can't turn them off, or even throttle them down.
Something I've always wondered, if one of the shuttle's SRBs fails to lit and the other one starts up, what happens?
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A quick google search and voilà!
More advanced solid rocket motors can not only be throttled but also be extinguished and then re-ignited by controlling the nozzle geometry or through the use of vent ports.
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Funny, a different article on wikipedia (Space Shuttle Abort Modes) claims that: "The SRBs cannot be turned off once ignited, and afterwards the shuttle is committed to take off. "
Wikipedia is contradicting itself? Noooooooooo!! *headasplode*
Re:Solid rockets (Score:5, Insightful)
> Wikipedia is contradicting itself?
No. There are extinguishable solid-fuel rockets. The shuttle SRBs are not among them.
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Restricting the nozzle of a solid rocket usually causes it to explode, so maybe you could "throttle" it by opening the nozzle, to reduce the burn rate. You might even be able to get it to blow itself out that way, I suppose.
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The spacecraft is clamped down until all engines are up to full power.
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That's true of the main engines, but not the solids. The explosive bolts holding the shuttle to the pad are fired before the SRBs are lit.
Re:Solid rockets (Score:4, Informative)
And the hold-down bolts are designed so that the thrust from the SRB would cause them to stretch and break loose, even if the pyrotechnic fasteners never fired.
To answer the original question, a launch where only one SRB fired would be an unsurvivable disaster. The asymmetric thrust would cause the shuttle to cartwheel into either the launch tower or the surrounding area.
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Thank you for the correction.
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The big drawback is that once they're lit you have no control, you can't turn them off, or even throttle them down.
Something I've always wondered, if one of the shuttle's SRBs fails to lit and the other one starts up, what happens?
Even though you can't turn off the booster you can detach it and use the range safety device to self destruct it. Have a look at "Space Shuttle Abort Modes" on Wikipedia.
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I recall there being a Range Safety system [wikipedia.org] that can be fired to split the SRB open, releasing the pressure. Odds are the RSO wouldn't be able to fire the charges in the 100 mS it takes to exceed load limits due to an asymmetrical SRB firing.
Re:Solid rockets (Score:4, Insightful)
Odds are the RSO wouldn't be able to fire the charges in the 100 mS it takes to exceed load limits due to an asymmetrical SRB firing.
Doesn't really matter, because everyone dies either way: the shuttle will crash and burn if it's on the pad with one SRB missing. All you have to do is ensure you destroy the SRB before it goes flying off across Florida and crashes into a bus full of nuns and orphans on their way to Disneyland.
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You mean Disneyworld [go.com]. It's the guys at Vandenberg [wikipedia.org] that have to avoid the nuns and orphans on their way to Disneyland [go.com] (still no picnic).
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Something I've always wondered, if one of the shuttle's SRBs fails to lit and the other one starts up, what happens?
Everyone dies. And the launch pad is probably destroyed.
This is why the SRBs have multiple (three I think) independent igniters so that only an extremely unlikely failure could make them not ignite.
Re:Solid rockets - Real Answer (Score:1)
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Yeah, basically. However SRMs are incredibly reliable in terms of lighting off. They are crap in many other respects, but I can't think of an instance where a vehicle launched from a pad like the shuttle had an ignition failure in an SRB.
Basically the drill is at T - 6 the SSMEs start. At that point it is still possible to abort. Once all 3 SSMEs are running at full power the clock hits 0, something like 6 pyro igniters in each SRM fires them up, and then maybe 500ms later the hold down bolts blow.
As for ra
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Yeah. Apparently a couple millimeter wide crack is ENOUGH, lol. Those SRMs were an abomination. Just seeing them even considering SRMs for Constellation was enough to tell me it would never fly. They really are NOT safe.
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The big drawback is that once they're lit you have no control, you can't turn them off, or even throttle them down.
Something I've always wondered, if one of the shuttle's SRBs fails to lit and the other one starts up, what happens?
At that point, you're fucked...
Redeeculous (Score:5, Informative)
Rocket fuel was a big research area in the 1950's. Dozens of very good chemists spent a whole load (hundreds of millions of 1950-size dollars) trying to make better rocket fuels.
( One of them wrote a informative and funny book about that time and place ).
The short summary is: Yes, you can make higher oomph rocket fuels and oxidizers with more oxygen in them.
But a lot of the formulas are impractical as:
(0) They were already discovered years ago, and discarded, but chemists don't like to write up their failures, and researchers don't like to read old moldy research summaries anyway.
(1) They're waaay too expensive to make, even for military uses.
(2) They are highly toxic, even more toxic than the widely-used hydrazines, which can kill you in several interesting ways.
(3) They're so unstable, you have to keep them under impossible conditions, like no sound, no vibrations, no light, and under a part per million of crud in the perfectly-smooth and unscratched nickel-plated tanks.
(4) They can't be stored for more than a day or so before the fuel or oxidizer starts decomposing itself or the tank walls.
(5) Too many of the researchers were vaporized while handling the stuff. Literally. Truly. Completely. That tends to make it hard to find substitute researchers to continue working with the same stuff.
(6) For military applications, you need a fuel that can be handled by raw recruits, stored for many months, be pumped quickly into not always totally clean rocket tanks, kept in those loaded rockets for days to months, and tolerate wide temperature swings. These requirements alone disqualify a large percentage of really zippy fuels and oxidizers.
The odds are pretty high against this "new" compound being all that new, or it passing the basic requirements for fuel or oxidizer.
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(3) They're so unstable, you have to keep them under impossible conditions, like no sound, no vibrations, no light, and under a part per million of crud in the perfectly-smooth and unscratched nickel-plated tanks.
If you manage to create these conditions, I'm sure a lot of husbands will pay good money to have their wifes stored under such conditions during their PMS days.
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Re:Redeeculous (Score:4, Informative)
Ignition!: An informal history of liquid rocket propellants
John D Clark, Rutgers University Press, 1972, ISBN-10: 0813507251
If your dad worked in oxidizers, he likely knows of this book.
http://www.amazon.com/Ignition-informal-history-liquid-propellants/dp/0813507251
Amazing book, some of the funniest science stories I have seen published (destroyer parts and bats!, boron!, etc...) - Any scientist would appreciate this.
Sadly, it is out of print, and copies run up to $200. I got it from my university library and scanned the whole thing.
You can order reprints from online sources.
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Re:Redeeculous (Score:4, Informative)
FWIW
http://thepiratebay.org/torrent/4822749/Ignition__An_informal_history_of_liquid_rocket_propellants [thepiratebay.org]
Re:Redeeculous (Score:4, Interesting)
(2) They are highly toxic, even more toxic than the widely-used hydrazines, which can kill you in several interesting ways.
(3) They're so unstable, you have to keep them under impossible conditions
That reminds me of a hazmat situation [tobaccodocuments.org] involving pentaborane [wikipedia.org] that happened in the 80's near me. One of my best friends as exposed, died and was resuscitated several times. He suffered organ damage and lost many of his early memories.
See also: http://www.scribd.com/doc/15062569/Pentaborane-Taming-the-Dragonpdf [scribd.com]
Re:Redeeculous (Score:5, Informative)
Agreed. If you want really high specific impulse fuel, then mono-atomic hydrogen, or possibly metallic hydrogen have fantastic theoretical performance. Atomic hydrogen can be easily produced (as a very low density gas), the "only" problem is stabilising it as a liquid or solid.
In reality the problem with launching to orbit is cost, and that cost is NOT dominated by fuel. As a rough estimate a saturn V used 1 million gallons of kerosine ($5M), to put 200K pounds in orbit. That is ~$25/pound. Whatever is the driving cost in space travel, it is not the cost of the fuel.
---Joe Frisch
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> Whatever is the driving cost in space travel, it is not the cost of the fuel.
No, it's the cost of the rocket. And cryogenic turbopumps are very expensive.
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Awww, shucks. You beat me to it.
But ONC looks fun to a symmetry-phile, and TNA has a similar appeal.
I wonder what their co-polymer would look like? Hopefully, like a hole in the lab bench.
Hmmm, by analogy with Arsenic and Phosphorus, one might hope for a N4 entity. One might also hope that, since hydrazine is so well known as a substitute for water when washing skin too delicate to take DHMO, then analogously N4H
A long shot (Score:4, Interesting)
Then it is being speculated that (a) the synthesis can be scaled up to produce a few hundred tonnes in a cost-effective way, (b) the stuff is stable enough to not decompose explosively if you shake it too hard, and (c) can be burnt in a controlled way to make it suitable as a rocket fuel.
A long shot. Unfortunately, it seems to be necessary nowadays to speculate about far-fetched applications in fundamental research, since the fact that a new compound consisting of just 4 nitrogen and 6 oxygen atoms is synthesized that has never been seen before, is not considered to be interesting by itself.
Mythbusters? (Score:1)
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Screw Jamie and Adam, this myth needs more Kari Byron
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Suit yourself, but I'd rather screw Kari Byron. Speaking of myths...
No hydrogen = poor exhaust velocity (Score:5, Interesting)
By the rocket equation, mass fraction is determined by velocity and exhaust velocity is driven two things; the mass of the molecules being put out and the pressure/temperature of the combustion chamber. The latter is limited, as once you get to about 100 atmospheres and 3000K you start to run out of materials to make the combustion chamber out of. Thus, molecule mass is the real driving factor - which is why despite the truly horrific engineering problems it entails, liquid hydrogen is a highly valued rocket fuel.
In fact, because molecular mass is so important, H2/O2 rockets are run fuel rich, sacrificing some combustion efficiency in order to leave some unburned hydrogen in the exhaust and reduce its average molecular mass.
So it doesn't matter how much energy you can get out of this new compound. It will only spit out oxygen, nitrogen and nitrous oxides, all far more massive than the hydrogen and water vapour you get from rockets in use at the moment. Sure, breaking down this molecule in optimal conditions might yield enough energy that the reaction products would have more velocity than the exhaust of a H2/O2 rocket, but there is a reason chemists don't build rockets; these researchers aren't taking into account the kind of unobtanium combustion chamber walls you would need to utilise such an inferno.
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Many of the "rockets in use at the moment" use fuels other than hydrogen and oxygen and many are solid fuel.
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And none of those other fuels has better performance that H2/O2, so whats your point?
The are three reasons why other fuels get used at all:
1. Lack of technology to handle liquid hydrogen
2. Need for a rocket (or more usually a missile) to loiter
3. Additional acceleration during the launch phase
1 and 2 don't apply any more to new rocket development, since even Russia and China can now handle LH2 and have stopped directly deriving their launchers from missiles. With 3 chamber pressure and temperature are again
Re:No hydrogen = poor exhaust velocity (Score:5, Informative)
The solid/liquid decision and the choice of fuel is a complex engineering process involving much more than picking the one with the highest ISP.
BTW lithium-flourine-hydrogen tripropellent has an ISP of 542, versus 455 for hydrogen-oxygen. By your reasoning everyone should be using it, but in fact it has never been used.
Nitrogycerin mixed with nitrocellulose was used in the past, but theoretical ISP is not the only consideration. Which is my point.
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By the rocket equation, mass fraction is determined by velocity and exhaust velocity is driven two things; the mass of the molecules being put out and the pressure/temperature of the combustion chamber.
A rocket goes up because of the asymmetry between molecules being flung against the top of the reaction chamber while passing out the bottom. I know that the chaos in the chamber means that the best way to think about this is a pressure parameter rather than the direction of individual molecules. But I've always wanted to know whether you could make a rocket engine more efficient by using electromagnetic fields to orient the molecules in such a way that the chemical reactions are biased to have more reacti
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Ah OK, thanks.
I'm hung up on conservation of momentum issues, when it may not apply (inelastic collisions?).
The nozzle probably works in the same way that sail shape allows a boat to beat upwind, and a wing's angle of attack generates lift.
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By the rocket equation, mass fraction is determined by velocity and exhaust velocity is driven two things; the mass of the molecules being put out and the pressure/temperature of the combustion chamber. The latter is limited, as once you get to about 100 atmospheres and 3000K you start to run out of materials to make the combustion chamber out of. Thus, molecule mass is the real driving factor - which is why despite the truly horrific engineering problems it entails, liquid hydrogen is a highly valued rocket fuel.
In fact, because molecular mass is so important, H2/O2 rockets are run fuel rich, sacrificing some combustion efficiency in order to leave some unburned hydrogen in the exhaust and reduce its average molecular mass.
...
Similarly the Germans improved the performance of the alcohol-LOX fueled V2 by adding inert water to the alcohol. By reducing the average molecular weight of the exhaust it improved the thrust even though it reduced the energy in the fuel.
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Not sure that was the intention actually; the main reason was that 1940s engineering couldn't build a combustion chamber that could withstand the heat of reaction between pure alcohol and LOx, and diluting the alcohol lowered the temperature (The actual chamber they used on the V2 was a massive, seat-of-the-pants, fudge anyhow). Lowering the carbon content of the fuel will have improved Isp certainly, but I don't believe that is why they made the choice.
"Rockets, Missiles, and Men in Space" by Willy Ley, 1968, p. 598:
"The fuel of the V-2 was ordinary ethyl alcohol... to which enough water had been added to bring its strength down to 75 percent by volume. The reason for the addition of the water was the following: ... The combustion products of burning ethyl alcohol are CO2 and H2O, and of course the CO2 molecule is by far the heavier. By adding water to the alcohol the proportion of water molecules in the exhaust is increased and its molecular weight dep
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By the rocket equation, mass fraction is determined by velocity and exhaust velocity is driven two things; the mass of the molecules being put out and the pressure/temperature of the combustion chamber. The latter is limited, as once you get to about 100 atmospheres and 3000K you start to run out of materials to make the combustion chamber out of. Thus, molecule mass is the real driving factor - which is why despite the truly horrific engineering problems it entails, liquid hydrogen is a highly valued rocket fuel.
At one stage apparently, they looked at Hydogen + Flourine. Most exothermic binary reactiion known? Check. Satisfactorily low reaction mass? Check.
Of course, quite apart from the horrific problems of dealing with liquid Flourine, the issue of that light reaction mass product, and its somewhat unfriendly characteristics led to it being abandoned.
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Well, you know Flourine = resembling flowers!
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> My spell check appears to have achieved malevolent sentience.
So has mine, and it resides inside my head.
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They probably wouldn't need a warhead, just make sure there's enough unspent fuel remaining. The explosion conflagration? Don't know the yield of that but HF is pretty lethal in minute amounts.
Single-stage-to-orbit, reusable vehicles... (Score:1)
Pick your poison (Score:1)
Environmentally friendly? (Score:3)
" What's more, the molecule consists only of nitrogen and oxygen, which would make the rocket fuel environmentally friendly."
I'm not saying that the byproducts of combustion will be dangerous but just because it is composed of only nitrogen and oxygen does not automatically make it "environmentally friendly". One of the major components of smog also consists of only oxygen and nitrogen. It's nitrogen dioxide.
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No, but it makes it PR friendly.
Verry funny (Score:3)
Nitrous oxide is also made up of only Nitrogen and Oxygen. Would we want that mixed into the air we breath? The very thought has me ROTFLMAO.
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how does it compare to the other t-word propellant (Score:2)
Does it have the power of thiotimoline [wikipedia.org] ?
Environmentally friendly ??!!!?!?! (Score:2)