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101 RD-180 engines for $1 billion. Thats $10 million per engine, built at the snail-like rate of 10 per year.
Are these engines more complex than gas turbine helo engines? Are the tolerances more exacting than for the engines used on commercial airliners?
In other words, if we purchased 100 RD-180s per year (or 1000) rather than 10 shouldn't the price actually fall once production lines start treating these things like commodities?
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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Hey, thats only about $5 million less then the RS-68 each
Actually yeah, I think they are probobly quite a bit more complex and delicate then a helecopter engine. For instance, the thing has to be able to handle the low temperatures of LOX and the turbines in the turbopump have to handle the much denser liquids instead of gasses. Much higher exhaust temperatures, preferably as high as possible, and extreme internal pressures. The 180 uses dual combustion chaimbers because the Russians couldn't figure out how to keep a single-chaimber engine that size from exploding.
If you expanded your production line by ten times, I doubt that would reduce the cost much, since it would require about ten times the reasources to make them being that rocket engines are very labor intensive. Besides, what do you need that many medium booster engines for? The worth of multiple medium lift launches is clearly pretty dubious without some non-payload guidence method and improve orbital construction capacity. An HLLV rocket would need a bigger engine too.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Don't forget the lesson of MER.
Building Spirit and Opportunity side by side meant they got two rovers for very little more than the price of one. The workers would install a part on one rover and then turn 180 degrees and install an identical part on the other.
Even hand made items are very much cheaper if made on an assembly line. Put RD-180s or RS-68s on parallel assembly lines. Workers walk between the lines and build 4 or 6 engines doing each task 4 or 6 times in rapid succession.
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My brother got in big trouble at his first ever computer job.
His consulting firm was hired to assemble hardware and install software on several hundred PCs for a Fortune 500 company and this was his first assignment in the field.
He was working 3rd shift and one night started opening the PC shipping boxes and setting the computers on a nearby work bench. After he plugged one in and while it was powering up, he opened another box and began unpackingd the power cables etc. . . before turning that one on.
Then, once a half dozen computers were running, he began installing the software. As one install program was running, he stepped over 2 feet and began another software install. Then another, and another.
A co-worker arrived and got very angry saying it was a violation of procedure to start a second software installation before the first was complete. You were supposed to either watch the screen as the program installed or go get coffee, but NOT start a 2nd installation.
:;):
Long story short, in one night he set a company record for successful assembly and install operations, with NO faults or flaws and the next morning his supervisor said to never, ever do that again. They had bid the job as needing two months and finishing in 10 days would just look bad.
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IMHO, this is why building 10x as many engines would lower costs, which means finding new demand is the key.
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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Yup sounds very familiar Bwhite with regards to manufacturing as a whole.
But I think Pratt an Whitney is also making that same engine here in the states if I recall correctly. I am sure that even if done efficiently it will still cost more only simply because of the higher labor costs involved since that is a unionized shop.
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No Bill, the bennefits of economies of scale varies from industry to industry, where in some fields it would have no bennefit at all. In the case of rocket engine construction, or anything that is highly labor intensive generally speaking (e.g. rocket engine construction) and not easily automated then the bennefits will be negligible.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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No Bill, the bennefits of economies of scale varies from industry to industry, where in some fields it would have no bennefit at all. In the case of rocket engine construction, or anything that is highly labor intensive generally speaking (e.g. rocket engine construction) and not easily automated then the bennefits will be negligible.
Building two MER rovers cost only slightly more than building one.
At a live presentation I attended on the project (in December 2003 before they landed) one of the rover team members commented on how easy it was to install a part on Spirit and then spin around 180 degrees and install the same part on Opportunity.
Building two MER rovers simultaneously took about 105% of the time needed to build just one.
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Option B - sacrifice a few percentage points of performance for vastly lower cost. Brian Feeney of the da Vicni X-prize team has spoken about using a $7,000 valve from the petroleum industry that weighed a few pounds more than the $70,000 custom made valve from the aerospace industry.
If this is done creatively, net cost per pound to LEO will go down even if abstract perfomance suffers.
Today, given the lack of demand, some industry studies suggest that a lower cost to LEO will merely reduce the total amount society spends on launch servcies rather than increasing the number of launches. If lower prices will not increase launch rates, there is no incentive not to sell the $70,000 valve.
Edited By BWhite on 1101744312
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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The trouble is Bill that you just can't do that. The amount of energy available from a given mass of fuel will limit the empty weight of the rocket to a small portion of the fuel weight. If you use heavier parts, either you severely sacrifice the already thin mass margins and so you have to make your rocket much bigger, which makes it more expensive and less reliable for the same payload.
Liquid hydrogen, the best fuel in the universe at the moment, has a mass ratio of somewhere below 10%. So, for every pound dry you add to the rocket (steel valve vs. titanium?), you have to add nine pounds of fuel in order to keep the same payload capacity. Thats not counting the extra tank weight or air resistance. Its not a linear relationship, its closer to exponential.
So there is a good engineering reason to keep dry weight as low as possible and to squeeze every last percent of performance out as you can, since small improvements will make a big difference in payload and vehicle size.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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The 180 uses dual combustion chaimbers because the Russians couldn't figure out how to keep a single-chaimber engine that size from exploding.
No. The Russians do make large, single chamber engines. The RD-0120 is just as large as SSME. The purpose for using two combustion chambers is to balance pressure in such a way that it increases specific impulse. The RD-701 engine uses cryogenic LOX/LH2 in its second mode of operation, when it isn't using 3 propellants, and it gets 460 seconds Isp in vacuum. That's only 1% higher than the 455 seconds of SSME, but it is the only engine with higher Isp than SSME. That's the result of blending the best of American technology (stolen by spies) and the best of Russian technology in a single engine. The Russian improvement is two combustion chambers with a single pump. Understand now?
The trouble is Bill that you just can't do that.
Actually you can. You do have to be careful of the issues you raise, but simple technology can reduce cost. I'll give you another example. In the 1970s a German company called OTRAG developed a low cost launch vehicle. It used industrial chemical pipes for propellant tanks, industrial chemical valves for propellant valves, Volkswagen windshield wiper motors to operate fuel valves, distributed microelectronics embedded in solid epoxy instead of a 1970s minicomputer the size of a refrigerator, nested stages one inside the other instead of stacked vertically, used differential thrust instead of gimbals to steer, and fuel was diesel fuel and nitric acid. It required baffles in the combustion chamber to damp oscillations in combustion chamber pressure, but it worked. Not a man-rated vehicle, but worked for satellites. The African country they launched from was politically unstable, so the project died due to politics. A low-tech big-dumb-booster may not have the highest payload mass fraction, but cost per pound to orbit is important, not mass on the launch pad.
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The trouble is Bill that you just can't do that. The amount of energy available from a given mass of fuel will limit the empty weight of the rocket to a small portion of the fuel weight. If you use heavier parts, either you severely sacrifice the already thin mass margins and so you have to make your rocket much bigger, which makes it more expensive and less reliable for the same payload.
Liquid hydrogen, the best fuel in the universe at the moment, has a mass ratio of somewhere below 10%. So, for every pound dry you add to the rocket (steel valve vs. titanium?), you have to add nine pounds of fuel in order to keep the same payload capacity. Thats not counting the extra tank weight or air resistance. Its not a linear relationship, its closer to exponential.
So there is a good engineering reason to keep dry weight as low as possible and to squeeze every last percent of performance out as you can, since small improvements will make a big difference in payload and vehicle size.
Form follows function. What are you lifting to LEO, and why?
As a general rule, if launches are rare, lighter is almost always better. If launches stop being rare, the equations change.
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If steel forces you below a useful payload mass, then titanium is the only choice. Otherwise, accepting a lower payload will reduce launch costs as measured by net per pound in LEO.
5500 pounds in LEO at $4200 per pound using titanium or 4800 pounds in LEO at $3700 per pound. Which is better?
Depends on your purpose. The answer is not always the same.
Suppose a steel valve weighs 30 pounds and costs $7,000. Titanium weighs 15 pounds and costs $70,000. To use steel reduces the net payload by 15 pounds and saves $63,000. If payload is worth more than $4,200 per pound, use titanium and carry an addditional 15 pounds to orbit. If payload is worth less than $4,200 per pound, use steel and lift 15 fewer pounds.
Lift 5485 instead of 5500 and save $63,000.
If its titanium at 10 pounds and $70,000 versus steel at 60 pounds and $20,000 the break point is $1000 per pound.
In the era of high launch costs, weight savings is essential.
As cost to LEO falls, however, there comes a point where buying two inexpensive "inefficient" rockets will place more mass in LEO for less money than 1 efficient rocket.
Edited By BWhite on 1101754527
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The RD-701 engine uses cryogenic LOX/LH2 in its second mode of operation, when it isn't using 3 propellants, and it gets 460 seconds Isp in vacuum. That's only 1% higher than the 455 seconds of SSME, but it is the only engine with higher Isp than SSME.
There are a lot of engines with higher Isp than the SSME. If you look at the latest generation of upper stage engines: MB-60: 467s, MB-35: 467s, Vinci: 467s, RL-60: 465s, RL-10b2: 465s. The SSME has good performance for a big lower stage engine, but there are lots of upper stage engines that can beat it.
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