The Last 10 Days In The Space Shuttle's Bunker?, Atlantis apparently to be scrapped in 2008 Options

[Guest_BruceMoomaw_*]

http://dsc.discovery.com/news/briefs/20060...lantis_spa.html :

"Under orders to retire the shuttle fleet by 2010, NASA plans to cancel shuttle Atlantis' next scheduled overhaul and mothball the ship in 2008.

"Rather than becoming a museum piece, however, Atlantis will serve as a spare parts donor for sister ships Discovery and Endeavour to complete assembly of the International Space Station.

" 'People are already calling us and asking us can they display one of our orbiters in their museum after we're done. I'm not giving anybody anything until we're all agreed the station is complete and the shuttles' job is done,' shuttle program manager Wayne Hale told Kennedy Space Center employees during a televised address on Friday.

" 'We're going to keep (Atlantis) in as near flight-ready condition as we can without putting it through a (modification and overhaul) so we can use those parts,' Hale said.
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Jeffrey Bell has recently finished a piece for "SpaceDaily" proclaiming that the wholesale cancellation of other NASA projects in the FY 2007 budget to keep Shuttle and ISS going is actually just part of Michael Griffin's Machiavellian strategy to get both of the cancelled, by making it clear that they can be saved now only at the cost of a swarm of other projects (including Bush's lunar program) which are now more popular. Certainly that is the overwhelming message being conveyed, whether Griffin planned it that way or not -- I haven't seen a single newspaper editorial yet that favors retaining Shuttle at this point.

(Bell also claims to see other, subtler evidence of this strategy in Griffin's moves over the last few weeks -- and also signs that he definitely plans to throw ISS from the train as well, by just giving it to the Russians half-finished in a few years and paying off the ESA and Japan for their unlaunched space lab modules. These include the fact that he's cancelled work on the unmanned cargo variant of the Crew Exploration Vehicle that will be necessary to take up replacement Control Moment Gyros to the ISS after the Shuttle is no longer available.)

[Guest_BruceMoomaw_*]

An excellent case can be made that the basic concept of the Shuttle was disastrously dumb-ass from the very beginning -- and Robert Truax made it in his January 1999 "Aerospace America" article, "The Future of Earth-to-Orbit Propulsion" ( http://www.teamprincipia.com/space/eto1.php ), which has been one of my Holy Tracts ever since I read it. Truax's most important point is that putting wings on a reusable LEO vehicle -- as opposed to a 2-stage vehicle in which the first stage parachutes into the ocean, and the second stage may or not be reusable -- is a breathtakingly idiotic notion from the start. Wings cut the vehicle's orbital payload by 2/3 (Griffin himself has memorably described the Shuttle as "a 100-ton shroud for a 30-ton payload"); they require absolute stability during reentry (whereas a capsule virtually stabilizes itself); they make a crash during the final landing vastly more likely; and they tremendously complicate any manned abort-and-escape (to the point of making it frequently impossible, as on the current Shuttle). They make sense on a vehicle that spends all its time moving horizontally through the atmosphere -- NOT on one that goes up through and then comes down through the atmosphere as fast as it reasonably can.

Actually, to quote his entire list of condemnations:

"Many flawed design choices were made in arriving at the Shuttle's final configuration:

"(1) Wings and landing gear are the heaviest of all possible methods of recovery.

"(2) Parallel staging is less efficient than tandem. More importantly, it also prevents the upper-stage engine from being optimized for vacuum operation. [He details this at some length, pointing out that it's particularly true for hydrogen-fueled engines.]

"(3) Use of two boosters doubles the probability of catastrophic failure. Multiple main engines increase probability of catastrophic failure by a factor of three, even though they may reduce the probability of noncatastrophic failure.

"(4) Opting for segmented booster cases increases the probability of case failure by unnecessarily complicating case design. Monolithic cases were proposed but rejected because Thiokol, a Utah company with no access to water transportation, had to propose a take-apart design.

"(5) Putting a crew on the first flight requires a very high reliability based on ground tests alone. A more sensible procedure would have been to fly the vehicle unmanned for cargo missions until an adequate degree of reliability could be demonstrated, as was done with the Saturn V (the Soviets, incidentally, did fly their shuttle Buran, for the first and only time, without a crew).

"(6) Use of solid propellants in the boosters minimizes the savings that can be had through recovery and reuse. Pressure-fed liquid-propellant boosters, as initially recommended by NASA-Marshall, would have required little more than a wash-down and refueling before reuse. Solids require disassembly and return to the factory, along with replacement of many parts. The cost of solid propellants runs about $7/lb vs. an average of about 10 cents for liquids.

"(7) Throwing away the largest part of the system, the main fuel tank, adds about $50 million to the cost per flight.

"(8) People and cargo should never be mixed. Payloads to be transported to orbit, even for missions requiring a human presence, are 95% 'stuff' and at most only 5% 'meat.' The provisions and safety requirements for the latter cost an order of magnitude more than for the former. Mixing the two burdens cargo flights with the same elaborate safety measures required for people."
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Some of Truax's arguments are open to question -- in particular, his belief that rockets should not only be recovered in but also launched from the ocean, and his belief that pressure-fed stages are better than turbopumps. (He got five approving letters from engineers in the April issue of the magazine, but also one detailed critique of that particular idea by an engineer who had worked on pressure-fed boosters and found out the hard way that they must be heavy and thus inefficient.) It may also be workable and economically effective to use the same booster for people and cargo, provided that any manned capsule is equipped with an escape rocket (which by itself will massively increase the safety of any manned mission, without having to go through the phenomenal expense of man-rating the booster to the degree that's necessary for the Shuttle).

And he was saying all this, loudly, in the 1970s, proposing an alternative to Shuttle called "Sea Dragon" that would have had these traits.

[mcaplinger]

An excellent case can be made that the basic concept of the Shuttle was disastrously dumb-ass from the very beginning -- and Robert Truax made it in his January 1999 "Aerospace America" article...

Regardless of the merits of Truax's technical points, the first rule of aerospace is that paper studies like his Sea Dragon are worthless by themselves. Until you have actually built, tested, and flown a system multiple times, you are only extrapolating based on incomplete data how it will perform, how well, and how cost-effectively. Talk is cheap, and aerospace is riddled with large and embarrassing failures based on ideas that seemed great on paper.

There's no shortage of people who trash the Shuttle with 20-20 hindsight, but the engineers who designed and built it did the best job they could under the technical and budgetary constraints at the time, and it's quite an achievement in that light. Within the limits of statistical error, its failure rate matches pretty well with the original honest assessment of 1 in 100 flights. If you want higher reliability than that, you'd better be prepared to pay for it, in money or capability or something.