GIGANTIC Aviation Week story, Pentagon has been flying 2-stage orbital spaceplane throughout 1990s |
GIGANTIC Aviation Week story, Pentagon has been flying 2-stage orbital spaceplane throughout 1990s |
Guest_BruceMoomaw_* |
Mar 6 2006, 02:24 AM
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#1
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Guests |
It may even have been manned:
http://www.aviationnow.com/avnow/news/chan...ws/030606p1.xml My God, what a story -- if it's even partially true. And, judging from this article, they are absolutely certain they have proof (along with proof that the thing, although it works, has recently been mothballed as not cost-effective). It's important to keep in mind, though, that this thing is NOT a workable prototype of the originally planned 2-stage winged Space Shuttle. The second stage -- the spaceplane that actually achieved orbit -- was relatively small and probably very inefficient as a cargo carrier; its advantage lay in allowing the US to get a military reconaissance (or weapons) satellite into orbit surreptitiously, with no advance warning of the launch going to other countries. Even at that, as I say, AW reports that the thing has been recently canned as not worth its (doubtless huge) black-budget expense. |
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Guest_BruceMoomaw_* |
Mar 6 2006, 10:53 PM
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#2
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Guests |
Fortunately the Soviet Union doesn't exist any longer, and even when it did I don't think they would have started a nuclear war every time a smallish missile or sounding rocket was launched anywhere in the World. Whoa, horsey. Russia -- under Yeltsin -- damn near started one in Jan. 1995 after misinterpreting the launch of a Norwegian scientific sounding rocket, which was far smaller than this thing would be. (See the Nov. 1997 "Scientific American" for the grisly details.) And, as I understand it, there were some very close calls earlier, during the Soviet days -- and not just on the Soviet side. You couldn't use the Spaceplane to sneak up on Russia, or any other nation that had missile-launch warning satellites -- but does even China have those? I don't think so. However, even if we decided to use the Spaceplane against nations that did lack that ability, the US would have had to inform Russia about the existence of the thing, while demanding that Russia keep the information to itself -- which is decidedly shaky practically. Regarding some of your other points: (1) "Actually it just about would. It would cut the deltavee needed for LEO from 9.5-10 kms-1 to something like 8.5 kms-1. With an Isp of 450 s (similar to the Shuttle main engine or the X-33 aerospike engine) this would require a fuel fraction in the 80-85% range which is perfectly practical for a small single stage ELV with a recoverable Corona-style capsule. Whether it is practical for a spaceplane is perhaps more dubious." But what you're talking about is just the equivalent of a Pegasus-type launch for military purposes. Maybe worth doing (if you ignore the difficulties mentioned above about Russia detecting the launch and spilling the beans), but hardly revolutionary. (2) "Since the Dyna Soar was meant to be launched from the ground by a Titan III it seems to me a rather smaller booster would suffice. A 40,000 lb booster does sound a bit on the small side to reach orbit, but not absurdly so." But a Titan 2 was needed to put Gemini into orbit -- and Dyna-Soar weighed 1/3 more. Even given the initial boost from the XB-70 (which might substitute for the Titan 2's first stage, I suppose, since I haven't yet checked their comparative speeds and payload masses), you'd need a very large second stage -- surely weighing more than 20 tons. So: I remain in the position, at this point, of pooh-poohing my own earlier Electrifying Announcement. Pretty much the story of my life. |
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