Inside the Tech of SpaceX's Homegrown Rocket Engine 82
An anonymous reader writes with this excerpt from a look at the engine behind SpaceX's Falcon rocket, the Merlin: "The rockstar of SpaceX may be Elon Musk, but the lead man behind the fire power is Tom Mueller. He is the Vice President of Propulsion Development and founding employee at SpaceX. Musk sought Mueller out in 2001 when Musk decided to build his own rockets instead of buying some from the Russians. Musk caught wind of a rocket engine Mueller built in his garage and 'apparently had a religious experience' once he saw it. If you didn't know, Elon Musk used $100 million of his Paypal money to start SpaceX. That money was used to build the Merlin engine Mueller had designed. The Merlin engine is the first new American booster engine in ten years and only the second in the last 25 years."
One of these Days Alice... (Score:5, Funny)
One of these days...
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Eventually we'll get back to the moon someday, and who knows what [facebook.com] we might find up there?
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That aliens watched us visit the moon and in 1975 left us a marker there underneath one of the Apollo Landers with the knowledge required build FTL communications.
All we have to do is go back and get it.
Well, malware alerts, for one thing... (Score:2)
I got a malware alert from the office trying TFA's link.
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What the hell reflects gamma-rays anyway? Neutronium?
A black hole's event horizon, from the inside? Kind of impractical for a nozzle, though.
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the secret is to bang the atoms together, guys (Score:2)
There's nothing "cheap" about antimatter.
Maybe for you filthy savages that are still trapped on planet Dirt.
You've got a 3.8 x 10^26 Watt fusion reactor, why don't you fucking use it?
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Mod parent up; // already posted in thread, so I can't.
We'd already be mining the moons of Saturn if atomic drives hadn't been scuttled.
Re:the secret is to bang the atoms together, guys (Score:4, Insightful)
Your endorsement falls flat when looked at in context. You are talking about atomic drives: hot gasses or ion propulsion from a fission reactor. The parent was talking about harnessing the power of the sun. Grandparent was talking about the difficulties in creating antimatter. Y'all need to get on the same page!
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Controlled fusion power has not really been practical. There is certainly some program with project like ITER [wikipedia.org] where a whole bunch of money is being poured into that kind of research (a total waste from my viewpoint, but some physics research may happen in spite of all of that money dumped down that rat hole).
Some other much more promising approaches include the Polywell [wikipedia.org] and Focus Fusion [wikipedia.org] concepts that seem to have some real theoretical potential, but none of these devices have been able to work out all of t
Re:Yet another firecracker (Score:5, Interesting)
I'm surprised you're so down on tokamak research which has actually produced large quantities of energy in tests (22MJ thermal in 1.5 seconds from the JET run in 1997, for example) while describing the con-artists like Polywell and Focus (zero joules in several years of funding and self-promotion) as "promising". At least you're not carrying a (fusion) torch for Fleischman and Pons.
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(22MJ thermal in 1.5 seconds from the JET run in 1997, for example)
22MJ/15 years gives an average power output of only 46 milliwatts.
Not a very impressive power station.
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It's a scientific instrument, not a power station.
That's what I was pointing out, for the benefit of those among us who might think that 22MJ somehow indicates any kind of significant progress towards an economically viable fusion power station.
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What a con man Robert Bussard was! He only spent most of his life working for NASA and the Atomic Energy Commission. Clearly he didn't know what he was doing, and only tried to make huge amounts of money from the government. Which is why he died broke and still looking for funding for his project. Weird how even after he died, the US navy picked the project up and is still working on it - with regular reviews by independent physicists.
The Polywell has taken something like 20M USD in its entire history, whe
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Intelligent folks often do crazy things outside their own specialist fields. Newton, the author of the Principia among other great works was an alchemist in his spare time, "studying" strange Kabbalistic nonsense. Linus Pauling went all weird in his later days too, the list goes on and on.
Just because Bussard was a smart guy in one field doesn't mean Polywell or focus fusion will work; the "and then a miracle occurs" stage is a big hurdle to pass. I class it in the "carburettor that runs on water" family
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Bussard was a nuclear physicist. This was not outside his field, it WAS his field. He worked on Tokamaks long before he began his adventures into electrostatic (electrodynamic? polywell is weird) fusion.
I don't 'believe' that Polywell will work. I think it's worth investigating, and the US navy is doing so. I am satisfied. They will decide if it works or not, and I will accept their conclusion. I am NOT a nuclear physicist, and do not pretend to be one.
But I have read enough, from Bussard and others, to dou
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Did you also know that plasma containment is getting better *faster* than Moore's law? In the last 20 years there has been a increase in containment of something like well over a million (can't be bothered looking it up). Also did you know that the ITER crowed
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That's fine. I didn't say 'defund ITER,' the materials science and plasma research IS valuable. What you said was 'defund Polywell and focus fusion' when they are taking a tiny portion of the funding pie. And like you said, if you kill those, it's not like ITER is going to see its budget increase.
I would appreciate it if you would focus on arguments instead of insulting the dead guy. Buzzard? Really?
I have read a bit about those experimental and theoretical results. Bussard & co seemd to think that they
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You called him Buzzard. That's a heck of a typo if you were not trying to be insulting. Saying it's against the theory and experiment is fine, and I gave you my reply to that.
Polywell has had several reviews, though we don't know the specifics. If I remember correctly, the project is only funded on a year-to-year basis, so the navy must think they're on to _something_. I wish that the results were public! Then we'd actually have something to argue over.
I'm a little bit surprised that you consider General Fu
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"Dabbled in Perpetual Motion a bit? Almost got it a couple of times?"
-- Professor Harold Hill, "The Music Man"
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Quoting the JT-60 [wikipedia.org] wiki page:
During deuterium (D–D fuel) plasma experiments in 1998 plasma conditions were achieved which would, if the D–D fuel were replaced with a 1:1 mix of deuterium and tritium (D–T fuel), have exceeded break-even—the point where the power produced by the fusion reactions equals the power supplied to operate the machine. JT-60 does not have the facilities to handle tritium; currently only the JET tokamak in the United Kingdom has such facilities. In fusion te
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Oh, one other comment about the JET test. It produced a pretty high peak output power, yes. But what was the percentage of input power? According to Wikipedia, it was about 65% of input. The reaction was nowhere near ignition.
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All of that energy after pouring how many billion dollars into the project? It sounds real impressive when you are talking megajoules, but that figure is only 6 kilowatt-hours if you turned it into more familiar power units that ordinary people use every day.
I would also say that Polywell and Focus have produced some energy... and in terms of a dollar per dollar rate of return it is pretty much equivalent. Fusion energy research is really going nowhere fast regardless of what technology you are talking ab
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Tokamaks have produced fusion energy -- the single run on JET produced a significant amount of energy (22MJ) for a macroscopic period (over a second) with a Q (energy return) of 0.65, and that's with a tokamak that was never designed to produce high Qs in the first place -- JET was and still is a research tool, limited to short bursts of plasma heating and magnetic confinement.
What's the best Q-factor result from Polywell fusion at the moment? I can't easily find figures on numbers from experimental hardw
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Also, any news on a gamma radiation reflector, a possible prerequisite to a propulsion with gamma rays from "cheaper" antimatter?
Prereq to a lot of weird stuff, including certain .mil toys you probably won't like very much. Probably would make an interesting hard sci fi novel.
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Prereq to a lot of weird stuff, including certain .mil toys you probably won't like very much. Probably would make an interesting hard sci fi novel.
I suspect you're referring to "Footfall" by Larry Niven & Jerry Pournelle.
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Antimatter does not need gamma ray reflectors. When a proton and and a antiproton combine you get Pions. Not gamma rays. About 1/3 is each of the pi+,pi- and pi0. The pi0 does almost immediately decay into gammas and there goes about 1/3 of the energy. But the pi+ and pi- live for long enough and are moving pretty close to the speed of light. Since they ar
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Do they make a pion-pion sound?
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What would a magnetic nozzle look like?
Ahh, nvm -- GIYF.
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New thing starts with one passionnate person. (Score:3, Insightful)
And not with a paid team working on a pay check.
Re:New thing starts with one passionnate person. (Score:4, Insightful)
Bullshit
Just off the top of my head: Teflon (dupont), the transistor (Bell Labs), the GUI (Xerox Parc), the blue LED (Nichia). The list goes on and on of things that have been major game changers that came from a group of smart people getting a paycheck putting their heads together or building on each other's work on something new.
That's not to say that there aren't impediments to innovation today, be it short sighted investors or patent issues, but a great deal of big innovations, if not many of the biggest in the last 100 years have come from academics on grants and guys on salaries. What seems to be special about SpaceX is that those are the guys that seem to be the focus in the company rather then much larger (less flat) companies that are mostly about managing management and pleasing investors.
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The list is endless
Simplify and add lightness (Score:5, Interesting)
No religious experience here (then again, never seen in person) but everything I've read is the Merlin series is all about Chapman's "simplify and add lightness" which a lot of the old time aerospace pioneers used to use before they became profit munching incumbent contractors.
Pintle injector for throttling, stability, and some wall cooling. Damn good idea.
Don't wanna run a completely isolated hydraulic system and include a zillion new single points of failure? Hmm how bout using the fuel as the hyd fluid. How bout pressurize the hydraulic "fluid" using the main turbopump. Damn good idea.
The vacuum model uses radiative cooling. I'm sure a fat cat modern contractor would try for regenerative just to boost the contract cost / profit, but they're the "simplify and add lightness" people so simple radiative. Hardly a new idea for vacuum nozzle cooling, but a damn good one anyway.
They also show great judgment in knowing their own limitations, they buy their turbopumps from a specialist. Things that need to be custom they do, things that can be COTS are COTS.
I hope they can stay on task with the whole "simplify and add lightness" thing. The X and XX sound a little more like something you'd see from the incumbents rather than startups. Unless they have secrets up their sleeves, which is certainly possible.
Maybe the standard /. car example is the Merlin is as minimal as can possibly be made that'll work, like a 60s muscle car engine or a race car engine, whereas the incumbents are more like a modern engine which is mostly an elaborate emissions control system, oh and with an engine bolted onto it almost as an afterthought.
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I think the incumbents are driven, to a certain extent, by NASA's desire to have the best possible, something that I'm sure the engineers and management at the contractors encourage. If you were a rocket engineer, would you want to work on just another engine from the 50s &60s, or something that pushes the state of the art of rocketry? (NASA has a legal and institutional mandate to do the latter, only)
the Shuttle Main Engine was described as probably the most sophisticated, highest performance rocket
Re:Simplify and add lightness (Score:5, Informative)
The engineers working on the shuttle engines were not necessarily trying to improve thrust; not trying to eke out an extra percent or two like a dragster or racecar mechanic would. They were just doing stuff like replacing a turbo pump with a different turbo pump that had half the moving parts, or changing the casting process so there were fewer welds; things that would make the engines lighter, more robust, and easier to manufacture.
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I always prefer removing heaviness instead of adding lightness...
Re:Simplify and add lightness (Score:5, Informative)
Not so much. You've eliminated the turbopump (trading that for a modest increase in fuel system complexity), but pretty much all the rest of the hydraulic system failure modes are still there.
A 'modern' contractor would probably use regenerative because it's a very efficient means of cooling, and modestly boosts engine performance by preheating the fluid (fuel or oxidizer) used for combustion.
One educated in the history of rocketry will know that regenerative cooling far predates the 'modern' contractor - and was chosen even when expensive and difficult. Someone intelligent would ponder on why that might be. Confronted with reality, the dogmatic simply ignores this and repeats his magic catchphrase like a cargo cultist.
No, they sound more like something you'd see from someone who wants/needs a certain level of performance and has the budget to go after it rather than fitting together a solution on the cheap. The dogmatic may prefer they stick with his mantra, but SpaceX seems to be made of pragmatists rather than dogmatics.
Spot on. Which means it's horribly inefficient compared to more modern designs, along with being heavier, with less efficient lubrication and cooling, and lower performing. It's the engine of the classic car enthusiast and the biased who believe that everything was better in some imaginary golden age. To everyone else, it's a quaint anachronism.
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Re:Simplify and add lightness (Score:4, Insightful)
I'm not an expert on rockets, and don't know if your comment is true or hyperbole. But it seems that the more modern designs costs 2x or more what SpaceX does to get to LEO. [wikipedia.org] How can such a horribly inefficient design cost so much less to fly?
There is no such thing as universal efficiency. A device/design is efficient if it uses less of whatever you desire to conserve. A rocket that is more mass efficient or more fuel efficient may not be cost efficient.
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Inefficiency isn't necessarily related to cost (and the fuel costs for space launches are pretty much lost in the rounding errors anyhow), but efficiency *is* directly related to performance.
Re:Simplify and add lightness (Score:4, Interesting)
In general, the Merlin as a booster engine is far lighter and much cheaper than hydrolox booster engines (but much more inneficient). They are slightly lighter and much cheaper than typical russian kerolox booster engines (and slightly less efficient than them).
I wouldn't say the Merlin is horribly inefficient, more that it's focused on optimizing cost and thrust to weight ratio rather than ISP. There really hasn't been much in the way of American development of kerolox engines lately. Most people focus on hydrolox development or buy Russian kerolox.
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Quite the contrary - there's been considerable work related to a revived F-1, and both NASA and the USAF have been looking at new hydrocarbon engines in order to get away from the Russian RD-180.
Lawsuit Coming? (Score:3)
"Merlin" is an engine brand of Rolls-Royce, a V12 piston engine from the 30's onwards used in a wide variety of aircraft. I can imagine raised eyebrows in their offices, but would they actually sue? I hope not, that would show these lawsuit-happy Yanks what British class really is.
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"Merlin" is an engine brand of Rolls-Royce, a V12 piston engine from the 30's onwards used in a wide variety of aircraft. I can imagine raised eyebrows in their offices, but would they actually sue? I hope not, that would show these lawsuit-happy Yanks what British class really is.
It's a different market segment, so the trademark can't be enforced in that way in the USA.
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The Rolls Royce Merlin is famous indeed. It was the engine that won the Battle of Britain.
http://www.bombercommandmuseum.ca/s,93_2merlin.html [bombercommandmuseum.ca]
culled some of the best of NASA too (Score:3)
Rotary Rocket Engines (Score:4, Interesting)
Goddard wanted to build spinning engines which used the rotary pressure to increase thrust-to-fuel ratio; visible in his posthumous patents.
Some basic info at (follow the links):
http://www.halfwaytoanywhere.com/ [halfwaytoanywhere.com]
No Garage here (Score:5, Informative)
I suggest you to look up TRW and the Low Cost Pintle Engine (LCPE) on the internet. Guess who was head of liquid rocket propulsion development there back at the start of the century.....
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I suggest you to look up TRW and the Low Cost Pintle Engine (LCPE) on the internet. Guess who was head of liquid rocket propulsion development there back at the start of the century.....
http://en.wikipedia.org/wiki/TR-106 [wikipedia.org]
Falcon BFR? (Score:2)
I didn't know about this... I guess the Falcon Heavy is still not enough for a manned Mars mission so they're gonna build the Big Fucking Rocket.
Glad I actually RTFA
Not bad (Score:1)
They're not breaking any records or anything but not bad. The MerlinC engine is around 300 Isp (specific impulse, the engine efficiency for those who don't know). That's not blowing away the Space shuttles specs (~400 Isp) but it also doesn't cost $40 Million per engine or use Liquid Hydrogen.