Here is a link to the Board Report. It is rather large at 248 pages (10mB).
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Columbia Accident Investigation Board Report
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GregLocock
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If they'd given NASA a bit more money would it really have been spent on the Shuttle? Doubt it.
Cheers
Greg Locock
Cheers
Greg Locock
The idea of flying a spacecraft as if it were an airplane might be fundamentally flawed. All the other issues (wings, wing tiles, wheels, wheel wells, shirtsleeve cabin environment during re-entry....) are complexities emanating from this single feature. The Apollo and Soyuz designs, while less heroic in concept, had more design success and a better safety record. Perhaps we would have been better off forgetting the "right stuff" and just following Occam's Razor(entities must not be multiplied beyond what is necessary) in our continuing quest for space.
You're neglecting that both Apollo and Soyuz were even higher re-entry speed vehicles with parachute retrieval. The heat shield was likewise a critical portion of the vehicle, for which a failure would likewise have been fatal to the crew.
Additionally, the Shuttle weight is more than 20 times that of the Apollo. Definitely beyond parachute recovery capacity. And if not parachute recoverable, that leaves either powered descent, which is essentially impossible given the fuel required, or a semi-controlled glide.
Apollo was neither re-usuable nor did it have any payload capacity besides its 3-man crew.
Additionally, Apollo was not without its fatalities and accidents. BUT the shuttle fleet has flown about 8 times as many flights as Apollo, so relatively speaking, the accident record is not necessarily different.
TTFN
Additionally, the Shuttle weight is more than 20 times that of the Apollo. Definitely beyond parachute recovery capacity. And if not parachute recoverable, that leaves either powered descent, which is essentially impossible given the fuel required, or a semi-controlled glide.
Apollo was neither re-usuable nor did it have any payload capacity besides its 3-man crew.
Additionally, Apollo was not without its fatalities and accidents. BUT the shuttle fleet has flown about 8 times as many flights as Apollo, so relatively speaking, the accident record is not necessarily different.
TTFN
IRstuff,
Yes, I'm aware of your points. Still, the costs, slow orbiter redeployment, and accident history indicate that the shuttle concept may not have been the best solution for supporting orbital activities, given the state of technology in the early 1970s when it was selected over competing concepts.
By the way, I mentioned Soyuz and Apollo only in terms of Occam's razor (minimum as appropriate for the job), not as potential shuttle concepts. Nevertheless, reusable, upsized Apollo and Gemini variants were seriously considered, in combination with heavy lift rockets, as alternatives to a shuttle for orbital transportation.
Unfortunately for NASA, calling the shuttle re-useable has turned out to be quite a stretch, since post-flight refurbishment and launch costs are said to be several hundred million dollars each. You may remember that the shuttle vehicle was initially sold as a low cost launcher that could be rapidly turned around in two weeks at most and do each mission for a maximum of $30 million. Inflation accounts for some of the difference, but not a factor of 10 or so.
The shuttle was originally supposed to be much smaller, but in order to drum up support in Washington, NASA got the Air Force to agree to use the shuttle instead of their own planned launch platforms (upgraded missiles). It was the Air Force payload weight and size requirements that made the shuttle so large; and its single-orbit-launch-and-return-to-Vandenberg mission that required delta wings. In the end, the Air Force went back to its missiles for most of its launches anyway, leaving NASA with a behemoth it hadn't initially wanted.
So the shuttle, impressive as it is (and it most certainly is), is based on a design concept created by an unusual degree of political compromise and squeezed by budget compromises over a period of 12 years. It's a wonder that it has done so well. The delta-winged concept has operational advantages, though not used, but the tiles, booster rockets, and huge external fuel tank have been true Achilles’ heels. The report cited in the first post of this thread lists other issues, such as the lack of crew protection and escape capabilities, in Chapter 10.
Yes, I'm aware of your points. Still, the costs, slow orbiter redeployment, and accident history indicate that the shuttle concept may not have been the best solution for supporting orbital activities, given the state of technology in the early 1970s when it was selected over competing concepts.
By the way, I mentioned Soyuz and Apollo only in terms of Occam's razor (minimum as appropriate for the job), not as potential shuttle concepts. Nevertheless, reusable, upsized Apollo and Gemini variants were seriously considered, in combination with heavy lift rockets, as alternatives to a shuttle for orbital transportation.
Unfortunately for NASA, calling the shuttle re-useable has turned out to be quite a stretch, since post-flight refurbishment and launch costs are said to be several hundred million dollars each. You may remember that the shuttle vehicle was initially sold as a low cost launcher that could be rapidly turned around in two weeks at most and do each mission for a maximum of $30 million. Inflation accounts for some of the difference, but not a factor of 10 or so.
The shuttle was originally supposed to be much smaller, but in order to drum up support in Washington, NASA got the Air Force to agree to use the shuttle instead of their own planned launch platforms (upgraded missiles). It was the Air Force payload weight and size requirements that made the shuttle so large; and its single-orbit-launch-and-return-to-Vandenberg mission that required delta wings. In the end, the Air Force went back to its missiles for most of its launches anyway, leaving NASA with a behemoth it hadn't initially wanted.
So the shuttle, impressive as it is (and it most certainly is), is based on a design concept created by an unusual degree of political compromise and squeezed by budget compromises over a period of 12 years. It's a wonder that it has done so well. The delta-winged concept has operational advantages, though not used, but the tiles, booster rockets, and huge external fuel tank have been true Achilles’ heels. The report cited in the first post of this thread lists other issues, such as the lack of crew protection and escape capabilities, in Chapter 10.
Actually, the number ONE reason tile refurbishment cost was and is so high is that NASA dropped the ball on the tiling concept. The existing tiling concept results in completely individual tiles, individually serialized, whereas, there are tiling designs that would have allowed the majority of the tiles to be identical and therefore substantially cheaper.
The fact that the Shuttle is political compromise is irrelevant, as political desires have been the hallmark of space development since Mercury. The sole political purpose of the space program was the Soviets
TTFN
The fact that the Shuttle is political compromise is irrelevant, as political desires have been the hallmark of space development since Mercury. The sole political purpose of the space program was the Soviets
TTFN
IRstuff,
I agree with your assessment of the tiles. I wondered from the first day I read about them why anyone would use such a complex, expensive, error prone scheme for heat shielding. The use of an advanced ablative coating was also considered in the shuttle design, and I am not sure why the serialized tiles were selected instead. Perhaps the tiles were considered more "reuseable".
Yes, politics always plays a role in government programs, but usually high level politics involves the programmatic aspects of a procurement (whether it is needed at all, number of units purchased, schedule, funding, deployment process, etc.) The hardware design is usually left to the procuring agencies to work out internally. And, yes, there are plenty of politics within those agencies, as well.
A good example is the current infighting over how to procure a new tanker fleet for the Air Force. The politics are about whether to buy or lease or some combination of both. They are not arguing at the OMB/Air Force top levels over whether the tankers should have straight vs. delta wings. On the other hand, the shuttle wrangling took such design issues all the way to the top.
That's why I stated that the shuttle design concepts were compromised by an unusual degree of political influence; and it is clear that the Columbia accident investigation report considers this issue to be relevant.
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