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Industrial Secrets in Rocket Design
In article ,
TangoMan wrote: How much is rocket design a standardized engineering discipline? Classical, conventional rocket design is pretty close to being standardized. (Although "ossified" might be a better word...) What I'm trying to grasp is whether the Atlas, Delta, Arianne, Zenit, etc have any design characteristics that stump their competitors to such a degree that they can't be duplicated... Generally not. Competitors might wonder about details, about whether (say) Zenit had found a particularly good way of addressing some specific issue, but not about how it could be addressed at all. The closest anybody comes to a real stumper is "how do the Russians make pump turbines stand up to oxidizer-rich preburner exhausts?", and while oxidizer-rich preburners were quite a surprise, once Western engineers were convinced that the idea should be taken seriously, they started having ideas about how it might be done. Do any of these rockets have breakthrough engineering that is unique to only their design or are they all whittling at the edges to gain minute efficiencies and they barely differ from each other in overall efficiency? Pretty much the latter. Breakthrough engineering is generally a gamble, and the political environment for large rockets in recent decades has strongly discouraged gambling. This is not to say that there aren't large advances to be had, only that the orthodox NASA-industrial complex is unlikely to produce them. Their big priority is to minimize the risk of embarrassing failures. (The original idea of X-planes was partly to try things out on a scale where failures would not be too embarrassing, so that unorthodox ideas could be evaluated in flight... but of late, while X-planes still have some latitude, NASA has been insisting that X-rockets must not fail. That was what killed X-34: NASA insisted on major new precautions against the slightest possibility of failure, but refused to pay the extra costs.) -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
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Industrial Secrets in Rocket Design
"Henry Spencer" wrote:
In article , TangoMan wrote: How much is rocket design a standardized engineering discipline? Classical, conventional rocket design is pretty close to being standardized. (Although "ossified" might be a better word...) This jogged my memory about something I'd been thinking about recently. Everyone knows how expensive the Shuttle is. Compared to other rockets the cost per kg of payload is several times higher. But that's being somewhat unfair to the Shuttle, in terms of evaluating how well the system does what it does (though, of course, it is quite fair to compare what you can use). As I've said more than once the Shuttle stack wastes a lot of mass with the orbiter, transforming a heavy lift launch on the scale of the Saturn V into something on the scale of the Titan IV. But think about it in terms of just putting mass into orbit. The Shuttle system deliver about 4x as much "useful" mass to orbit as its cargo payload, so it's cost per kg to orbit is thus about 4x higher than what it really ought to be. With an OSP or Apollo launch (for example) they'd count the capsule as part of the payload, though for the Shuttle they don't. Anywho, look at it that way and you see something which, I think, is pretty disturbing. The Shuttle's cost figures are in the *same* range as for other launchers except a small handful of very cheap launchers (like Soyuz). So, really, vehicles like the Atlas V aren't that much of an improvement in cost over the Shuttle, behind the scenes it's still more or less the same stuff going on and the same costs. Certainly it's good to avoid that payload waste but I think it's more than a little unsettling that despite a whole new generation of launch vehicles, things haven't budged much. |
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