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OSP: reliability and survivability
In deciding whether or not to fund NASA's proposed Orbital Space Plane
- a "space taxi" dedicated to crew transport, in contrast to the current "space truck" - Congressional mavens are making a faulty assumption. That is that because OSP will be launched on unproven Delta and Atlas-family rockets, it will be fundamentally no more reliable than the Shuttle. Because OSP will be costly, it follows that it makes more sense to upgrade the Shuttle than to build a new spacecraft. This is correct on its own narrow terms - rockets tend to explode at least 1% of the time, despite the best efforts of engineers. However, putting the OSP on top of the launch stack makes it an inherently survivable vehicle; rockets can drag the plane clear of a fireball, and launch debris won't fall onto the vehicle. The OSP becomes its own ejector seat. The shuttle, in contrast, can be made more reliable but is inherently unsurvivable. The Challenger and Columbia incidents only became disasters because of the Orbiter's placement to one side of the launch stack. One way round this is to build a B-1B type Crew Escape Module into the middeck, but this would involve a partial rebuild of the three remaining Orbiters. No. Don't upgrade the Shuttle beyond the measures suggested in the Gehman report. Let's put all our energies into building a reliable, survivable replacement. Fly the Shuttle only as many times as are needed to complete the Station, then - ASAP - put these dinosaurs into mothballs. Time for a change. Edwin Kite undergraduate Cambridge University, UK |
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reliability and survivability
"Edwin Kite" wrote in message om... In deciding whether or not to fund NASA's proposed Orbital Space Plane - a "space taxi" dedicated to crew transport, in contrast to the current "space truck" - Congressional mavens are making a faulty assumption. That is that because OSP will be launched on unproven Delta and Atlas-family rockets, it will be fundamentally no more reliable than the Shuttle. Because OSP will be costly, it follows that it makes more sense to upgrade the Shuttle than to build a new spacecraft. This is correct on its own narrow terms - rockets tend to explode at least 1% of the time, despite the best efforts of engineers. However, putting the OSP on top of the launch stack makes it an inherently survivable vehicle; rockets can drag the plane clear of a fireball, and launch debris won't fall onto the vehicle. The OSP becomes its own ejector seat. The shuttle, in contrast, can be made more reliable but is inherently unsurvivable. The Challenger and Columbia incidents only became disasters because of the Orbiter's placement to one side of the launch stack. One way round this is to build a B-1B type Crew Escape Module into the middeck, but this would involve a partial rebuild of the three remaining Orbiters. No. Don't upgrade the Shuttle beyond the measures suggested in the Gehman report. Let's put all our energies into building a reliable, survivable replacement. Fly the Shuttle only as many times as are needed to complete the Station, then - ASAP - put these dinosaurs into mothballs. Time for a change. You guys just don't get it, do you? All technical and engineering analysis will say that the Shuttle is generally safe and logically speaking it makes more sense to keep the Shuttle flying for as long as needed. However, politicians and the U.S. public aren't on the same frequency with engineers. Their call for a Shuttle replacement is purely based on the *subjective* feeling that the Shuttle is unsafe and is tainted. Yet, these are the people that decide wether the Shuttle will be replaced or not. Conclusion: the Shuttle will be replaced with a decade. As soon as the OSP is flying, I'll bet you that NASA will present a plan to take the remaining Shuttles out of service. |
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reliability and survivability
Ultimate Buu wrote:
You guys just don't get it, do you? All technical and engineering analysis will say that the Shuttle is generally safe and logically speaking it makes more sense to keep the Shuttle flying for as long as needed. I do not agree to this statement. There are several flaws in the shuttle system,making it unsafe, which could only be solved by a complete redesign. (Eg. Tank isolation, hydrogen fuel lines which leak every few launches) However, politicians and the U.S. public aren't on the same frequency with engineers. Their call for a Shuttle replacement is purely based on the subjective feeling that the Shuttle is unsafe and is tainted. Yet, these are the people that decide wether the Shuttle will be replaced or not. Conclusion: the Shuttle will be replaced with a decade. As soon as the OSP is flying, I'll bet you that NASA will present a plan to take the remaining Shuttles out of service. Do you really think NASA will be able to build OSP, or any other manned craft? Considering their performance in the last two decades, I really doubt OSP will succeed, rather than being scrapped midway because of cost overruns and underperformance. The US should put the remaining shuttles into museums, maybe after some last missions like launching ISS-parts which cannot be done otherwise. However, the shuttle was a try at building a low cost manned launcher which did not succeed, and rather than fix what cannot be fixed the US should build one or more successors incorporating the lessons learned. Robert Kitzmueller |
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reliability and survivability
Ultimate Buu wrote:
You guys just don't get it, do you? All technical and engineering analysis will say that the Shuttle is generally safe and logically speaking it makes more sense to keep the Shuttle flying for as long as needed. The flat failure of any *economic* analysis to support the shuttle is the problem. Engineering analysis is a strictly secondary problem. However, politicians and the U.S. public aren't on the same frequency with engineers. Their call for a Shuttle replacement is purely based on the *subjective* feeling that the Shuttle is unsafe and is tainted. Seeing as we've had two LOO/LOC accidents in 113 flights, it seems to me there is pretty *objective* reason to doubt the safety of the shuttle. Engineering analysis may show that if all the right measures are taken and all the right procedures are followed everything will be OK. No amount of analysis can guarantee that the procedures will in fact be followed, nor the measures taken. In fact, we have clear evidence based on experience to suggest that at least some procedures will not be followed. The logical conclusion is that the design must allow for the fact that the vehicle will be operated by humans as opposed to the flawless engineers assumed in NASA analyses. This requires serious redesign or outright replacement of the shuttle. .......Andrew -- -- Andrew Case | | |
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reliability and survivability
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reliability and survivability
LooseChanj wrote:
On or about 8 Sep 2003 22:10:01 GMT, Derek Lyons made the sensational claim that: Anyone who believes that we can engineer a vehicle of air, ground, sea, or space that will never suffer a LOC/LOV accident is living in a fantasy world. Engineering a vehicle that can't experience an LOC is easy. Just don't put people on it! That's fine, until you come to those times when people *are* the payload.... And if the vehicle (not to mention many inanimate payloads like satcoms, big space telescopes, or nuclear powered probes) is sufficently expensive and valuable, you want just about as much certainty of its ssuccessful flight and return, as if it *were* manned. Unmanned doesn't always equal expendable. |
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reliability and survivability
Andrew Case wrote:
The flat failure of any *economic* analysis to support the shuttle is the problem. Actually the original analysis supported the shuttle of course. Probably you meant *accurate* economic analysis :-) Gotta thank Tricky Dicky Nixon for this one. Check it out: http://www.spacedaily.com/news/shuttle-03p1.html Very, very rough summary: 'oh yeah, we lied to congress big time, there was no way we could or would launch 52 times per year which is what is needed to make the Shuttle cost-effective, but Nixon knew that and knowingly signed off on it anyway. p.s. didn't we mention how fragile the leading edges are? Oops, I'm sure we must have.' Lovely. ......Andrew |
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reliability and survivability
Ian Woollard wrote:
http://www.spacedaily.com/news/shuttle-03p1.html Very, very rough summary: Rougher summary; There is no evidence to cite this individuals claims. Rough, but true, statement: The journalistic and editorial standards of Space Daily are low at best. D. -- The STS-107 Columbia Loss FAQ can be found at the following URLs: Text-Only Version: http://www.io.com/~o_m/columbia_loss_faq.html Enhanced HTML Version: http://www.io.com/~o_m/columbia_loss_faq_x.html Corrections, comments, and additions should be e-mailed to , as well as posted to sci.space.history and sci.space.shuttle for discussion. |
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OSP: reliability and survivability
On 6 Sep 2003 13:55:04 GMT, in a place far, far away,
(Edwin Kite) made the phosphor on my monitor glow in such a way as to indicate that: In deciding whether or not to fund NASA's proposed Orbital Space Plane - a "space taxi" dedicated to crew transport, in contrast to the current "space truck" - Congressional mavens are making a faulty assumption. That is that because OSP will be launched on unproven Delta and Atlas-family rockets, it will be fundamentally no more reliable than the Shuttle. While this is true, the theory is not that OSP will be more reliable, but that it will be safer (i.e., provide a better chance of crew survival). Because OSP will be costly, it follows that it makes more sense to upgrade the Shuttle than to build a new spacecraft. Actually, neither makes economic sense. This is correct on its own narrow terms - rockets tend to explode at least 1% of the time, despite the best efforts of engineers. Expendable rockets do. We've no experience base with reusables, other than Shuttle, which has never exploded... -- simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole) interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org "Extraordinary launch vehicles require extraordinary markets..." Swap the first . and @ and throw out the ".trash" to email me. Here's my email address for autospammers: |
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