|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
reliability and survivability
Derek Lyons wrote: That's not an open and shut case. Both losses, while certainly chargeable to design, could have been avoided by reasonable operational procedures. in Challenger's case, yes- although the SRB design was flawed in regard to O-ring sealing, the avoidance of cold weather launches would probably have meant that no vehicle loss would have resulted from that design limitation; but the insulation shedding due to "popcorning" of the ET's insulation, and the shedding of the bipod rampsunder aerodynamic stress, as well as the flaw in the bolt catchers that were cited in the CAIB's report were basic design flaws that were waiting to claim an orbiter sooner or later- the bolt catchers should be an easy fix...but the insulation shedding is a basic and fundamental problem with the design strategy underlying the ET's construction, and might require considerable rethinking of its design and construction if the "zero-shedding" original requirement is to be met. Even small pieces of the insulation falling off were damaging the TPS on almost every flight. 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. It's not a matter of "never"... it's a matter of "how often". Pat |
#12
|
|||
|
|||
reliability and survivability
HAESSIG Frédéric Pierre Tamatoa wrote: Remember that Ariane V is supposed to be Man-rated ( triple redundancy ). Would you take a flight on it at this time? Not if they pop the champagne at lift-off....as opposed to orbital entry- I wouldn't...there is such a thing as "Asking For It". Pat |
#13
|
|||
|
|||
OSP: reliability and survivability
Earl Colby Pottinger wrote: What that means that you don't do what NASA does just because they did. As you already pointed out, if the ROTON used drop tanks then you drop them when you have to abort. If you use booster rockets make then hybrids or liquid fuel. But why assume that ROTON will use solids just because NASA does. As soon as you get away from the solid booster idea, the cost of design starts going way up, you have just moved into unknown (at least for the U.S.) territory. Pat |
#14
|
|||
|
|||
OSP: reliability and survivability
Pat Flannery :
Earl Colby Pottinger wrote: What that means that you don't do what NASA does just because they did. As you already pointed out, if the ROTON used drop tanks then you drop them when you have to abort. If you use booster rockets make then hybrids or liquid fuel. But why assume that ROTON will use solids just because NASA does. As soon as you get away from the solid booster idea, the cost of design starts going way up, you have just moved into unknown (at least for the U.S.) territory. I find that hard to believe, first the ROTON was already a large move away from standard US designs even after they oved to the Fastrac engine. Second, we don't need NASA-type super expensive junk as boosters, just something that develops lots of thrust. While I admit large hybrids may have hidden got-yous, what about pressure feeded peroxide rockets. Remember I mean boosters only! The ROTON people already had access to a working peroxide engine, they already made composite tanks. No regulator, fill the tanks two thirds and pressurize them, simple valves to turn them on, the ROTON does the steering and the boosters may or may not have a recovery system, your choice based on costs. Earl Colby Pottinger -- I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos, SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to the time? http://webhome.idirect.com/~earlcp |
#15
|
|||
|
|||
OSP: reliability and survivability
Earl Colby Pottinger wrote: I find that hard to believe, first the ROTON was already a large move away from standard US designs even after they oved to the Fastrac engine. Second, we don't need NASA-type super expensive junk as boosters, just something that develops lots of thrust. While I admit large hybrids may have hidden got-yous, what about pressure feeded peroxide rockets. Remember I mean boosters only! The ROTON people already had access to a working peroxide engine, they already made composite tanks. No regulator, fill the tanks two thirds and pressurize them, simple valves to turn them on, the ROTON does the steering and the boosters may or may not have a recovery system, your choice based on costs. Oddly, the hydrogen peroxide option occurred to me also after I wrote the last post; there would be at least three ways of going about it; each with their pluses and minuses: Simple catalytic decomposition of hydrogen peroxide into superheated steam and oxygen- this would be very easy to accomplish, and very reliable...but the ISP would suck, and the weight of the pressurized peroxide tank would make for a pretty inefficient design in regards to weight versus performance. but the weight of the tankage would still be quite high...although if ocean recovery of the spent boosters was intended, pressure fed hydrogen peroxide and a fuel- such as kerosene- which burns with the oxygen freed in the catalytic reactions the hydrogen peroxide decomposes; this would also be very simple and reliable, you would get a better ISP than the first option, their inherent toughness might be an advantage. A hydrogen peroxide/fuel driven engine using the hydrogen peroxide both as an oxidizer; and via its decomposition as a method of driving a turbopump for propellant feed- this is a more involved process, but has the advantage of a better ISP and lower booster weight in regards to its thrust- the technology was already proven by both the Germans during W.W. II with the Walter motor for the ME-163 Komet rocket fighter: http://www.walter-rockets.i12.com/hw/sitemap.htm and the British Gamma motor as used on the Black Arrow satellite launcher: http://members.aol.com/nicholashl/ukspace/htp/htp.htm the technology is fairly basic, and the high density of hydrogen peroxide in comparison to LOX makes for more compact tankage. It well be interesting to see how well the simple hybrid motor for Rutan's Spaceship One performs in actual operations, if it is reliable, such motors may combine the simplicity of solids with both a (somewhat inefficient) throttlable aspect- as well as safe in-flight shutdown via stopping the oxidizer flow. Pat |
#16
|
|||
|
|||
Cheap boosters for reliability and survivability
Pat Flannery :
Earl Colby Pottinger wrote: I find that hard to believe, first the ROTON was already a large move away from standard US designs even after they moved to the Fastrac engine. Second, we don't need NASA-type super expensive junk as boosters, just something that develops lots of thrust. While I admit large hybrids may have hidden got-yous, what about pressure feeded peroxide rockets. Remember I mean boosters only! The ROTON people already had access to a working peroxide engine, they already made composite tanks. No regulator, just fill the tanks two thirds and pressurize them, simple valves to turn them on, the ROTON does the steering and the boosters may or may not have a recovery system, your choice based on costs. Oddly, the hydrogen peroxide option occurred to me also after I wrote the last post; there would be at least three ways of going about it; each with their pluses and minuses: Simple catalytic decomposition of hydrogen peroxide into superheated steam and oxygen - this would be very easy to accomplish, and very reliable...but the ISP would suck, and the weight of the pressurized peroxide tank would make for a pretty inefficient design in regards to weight versus performance. Remember John Carmack's work in boosting peroxide ISP. You can still keep it a simple mono-propellant that helps a lot. But the weight of the tankage would still be quite high...although if ocean recovery of the spent boosters was intended, pressure fed hydrogen peroxide and a fuel- such as kerosene- which burns with the oxygen freed in the catalytic reactions the hydrogen peroxide decomposes; this would also be very simple and reliable, you would get a better ISP than the first option, their inherent toughness might be an advantage. For ease of handling and cleanup, I prefer alcohol as the fuel. A hydrogen peroxide/fuel driven engine using the hydrogen peroxide both as an oxidizer; and via its decomposition as a method of driving a turbopump for propellant feed- this is a more involved process, but has the advantage of a better ISP and lower booster weight in regards to its thrust- the technology was already proven by both the Germans during W.W. II with the Walter motor for the ME-163 Komet rocket fighter: http://www.walter-rockets.i12.com/hw/sitemap.htm and the British Gamma motor as used on the Black Arrow satellite launcher: http://members.aol.com/nicholashl/ukspace/htp/htp.htm the technology is fairly basic, and the high density of hydrogen peroxide in comparison to LOX makes for more compact tankage. For a simple booster, I would prefer to stay away from turbopumps and stick to pressure feeded systems. It well be interesting to see how well the simple hybrid motor for Rutan's Spaceship One performs in actual operations, if it is reliable, such motors may combine the simplicity of solids with both a (somewhat inefficient) throttlable aspect- as well as safe in-flight shutdown via stopping the oxidizer flow. Pat Scaling up may be a problem, but yes, hybrids are also a good choice as you can turn them off easyly and fast. Earl Colby Pottinger -- I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos, SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to the time? http://webhome.idirect.com/~earlcp |
#17
|
|||
|
|||
OSP: reliability and survivability
Pat Flannery wrote: Whoops something went missing here... the mail program was acting flukey...it should have read: The second alternative would be to use the oxygen generated by the decomposition of the hydrogen peroxide but the weight of the tankage would still be quite high...although if ocean recovery of the spent boosters was intended, pressure fed hydrogen peroxide and a fuel- such as kerosene- which burns with the oxygen freed in the catalytic reactions of the hydrogen peroxide as it decomposes would also be very simple and reliable- you would get a better ISP than the first option, and the pressurized tankage's inherent toughness might be an advantage. A hydrogen peroxide/fuel driven engine using the hydrogen peroxide both as an oxidizer; and via its decomposition as a method of driving a turbopump for propellant feed- this is a more involved process, but has the advantage of a better ISP and lower booster weight in regards to its thrust- the technology was already proven by both the Germans during W.W. II with the Walter motor for the ME-163 Komet rocket fighter: http://www.walter-rockets.i12.com/hw/sitemap.htm and the British Gamma motor as used on the Black Arrow satellite launcher: http://members.aol.com/nicholashl/ukspace/htp/htp.htm the technology is fairly basic, and the high density of hydrogen peroxide in comparison to LOX makes for more compact tankage. It well be interesting to see how well the simple hybrid motor for Rutan's Spaceship One performs in actual operations, if it is reliable, such motors may combine the simplicity of solids with both a (somewhat inefficient) throttlable aspect- as well as safe in-flight shutdown via stopping the oxidizer flow. Pat |
#18
|
|||
|
|||
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. |
#19
|
|||
|
|||
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 |
#20
|
|||
|
|||
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. |
Thread Tools | |
Display Modes | |
|
|