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I have a question: NASA plans to start development of a Shuttle replacement (second generation RLV) sometime around 2010 so that it will be operational by 2020. Originally it was planned to begin development of such a vehicle in 2006 after years of technology development and paper studies (SLI) and to have it operational by 2012. Now they say the OSP will be developed first. SLI has largely been scrapped and what remains is now called the NGLT (Next Generation Launch Technology) program and it's becoming more and more of a joint NASA/DoD program. So far so good. Now my question: Contained within that NGLT program are so called "third generation RLV efforts" and NASA seems determined to have a HTHL scramjet spaceplane as its third generation RLV. There are plans to fly the X-43B in 2010. This craft will be the first one to be powered by a combined cycle engine and will pave the way, according to NASA, for a "Large-Scale Reusable Demonstrator Vehicle" (first flight in 2016) which will finally lead to an operational third generation RLV in 2025. Why then do we need a second generation RLV (probably a "conventional", i.e. rocket powered TSTO design) which would be operational just five years earlier? Surely NASA will not retire its second generation RLV, which will have cost billions to develop, after just five years of service to replace it with a new third generation RLV??? Keep in mind that the Shuttle ('first generation RLV') is currently planned to remain in service until 2022 (!) And where is the money for two multibillion dollar development programs (second and third generation RLV) going to come from???
NASA must develop a coherent longterm strategy for developing a Shuttle replacement within the next 15 years and stop making new plans (that don't make any sense) and revising the whole program again and again so that nothing gets ever build!
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NASA has no "coherent" RLV strategy. And, IMHO, NASA should have NO RLV strategy. Any RLV whose general design is dictated by NASA will be doomed to failure. If the Air Force and NASA get together to specify a vehicle, it will turn into another Shuttle debacle.
I think that NASA's answer will come, indirectly, from the X-Prize. Teams like Cosmopolis, DaVinci, Canadian Arrow, Star Chaser, Burt Rutan, Armadillo, and X-Cor all have tremendous potential. I feel that if any of these firms can tap into the suborbital space tourism market, an orbital spacecraft will certainly be developed. I also have optimism that the industry is looking at developing their own RLVs. A Boeing official once said that Delta IV would be Boeing's last RLV. A third route is DARPA, whose projects like RASCAL are inspiring the impossible.
Right now, NASA is struggling with scramjets and trying to determine whether they are worth NASA's time. Once the X-43 flies, you will see NASA's plans firm up. But I still think that NASA should stick to research and let the industry build and operate the vehicle.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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AA: what do you think of Bristol's design? I think its a fairly conservative design with strong potential.
And what do you think about SCs capsule, the Nova 2/Thunderbird, that they just revealed?
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I think Bristol's design philosophy is sound, but I think their performance estimates are optimistic. The Ascender will be hampered by the jets and the runway takeoff (bigger wings + jets = higher weight + lower performance.) Hydrogen fuel is also a negative because much of it will boil off while the Ascender is under jet power (look at the figures for oxidizer boil-off during the X-15's flight to release altitude; you'll see what I mean.) The Spacecab and Spacebus follow-ons are a bit optimistic about the speeds they will achieve using turbojet engines.
Starchaser is following a conservative design philosphy that will make them a contender for the X-Prize (they've already finished most of their testing,) but it's commercial prospects will probably be limited. I just don't think that people will enjoy being squashed in a capsule for their brief spaceflight.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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Bill Sweetman has a pretty good article in Popular Science about the rise and fall of the Space Launch Initiative.
What we've seen from NASA over the past decade is a history of mismanagement, with X-33, X-34, X-38, and SLI being the prime examples. Sweetman focuses on NASA's stringient requirements for cost and safety on the shuttle.
NASA has said that it wants a factor of ten reduction in the cost of operating its new spacecraft. Yet it would still be agreeable if we could get a factor of four, or even a factor of two, when you're spending three billion annually on the current shuttle. Further, it is unreasonable to expect 10,000 launches without vehicle failure when the chances of failure in the previous vehicle were 1 in 56.5. It is more reasonable to design the spacecraft that gives the crew multiple means of escaping disaster--in both the ascent and descent stages. Crew survivability, not vehicle survivability, should be the deciding factor.
I also suspect that SLI was scaled back under pressure from Boeing and Lockheed Martin. When looking at their SLI designs, it was clear that they hadn't put in as much thought as Northrop-Grumman/OSC. And I suspect its because the SLI booster would be a direct competitor with their Delta IV and Atlas V, and if it were developed it would end their chances of recouping their original investment in the expendable rockets.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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topic fixed....
Its funny how we still are wrestling with the reusability question a decade plus later....
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