edkyle99 - 13/7/2006 12:56 PMQuoteJim - 13/7/2006 10:28 AMQuoteedkyle99 - 13/7/2006 11:04 AMI don't breath until wheels stop on the runway. Fair to mention, by the way, that liquid boosters fail more often than solids. Just look at the recent GSLV failure from India, for one example. GSLV has a powerful solid booster core with four strap-on liquid boosters. The solid worked fine. One of the liquids failed. There have been three launch failures this year so far, in 31 attempts. All of the failures involved liquid propulsion systems. Last year there were three failures in 55 attempts. All of the failures were liquids. Three of the four failures in 2004 were liquids. The solid rocket failure (Shavit) involved a failed stage separation. Etc. - Ed Kylethe liquied failures are surivable. The rest of the world is not a good database. Spacex and India are not in the same population as the US and Russia wrt spacelaunchIf we only look at US launch vehicles since 1980 (including all shuttle launches), there have been 605 by my count with 36 launch vehicle failures. Of these, I can only identify four that were clearly solid rocket motor failures: STS-51L, Delta 241, Titan 4 K-11, and Titan 34D-9. I count at least nine that were clearly liquid propulsion system failures: AC-62, AC-70, AC-71, AC-74, Atlas 19F, Delta 178, Delta 269, Titan 34D-7, and Titan 34D-3. There may have been others, as a few of the DoD launches are listed cryptically as "failed to orbit" on my list. - Ed Kyle
Jim - 13/7/2006 10:28 AMQuoteedkyle99 - 13/7/2006 11:04 AMI don't breath until wheels stop on the runway. Fair to mention, by the way, that liquid boosters fail more often than solids. Just look at the recent GSLV failure from India, for one example. GSLV has a powerful solid booster core with four strap-on liquid boosters. The solid worked fine. One of the liquids failed. There have been three launch failures this year so far, in 31 attempts. All of the failures involved liquid propulsion systems. Last year there were three failures in 55 attempts. All of the failures were liquids. Three of the four failures in 2004 were liquids. The solid rocket failure (Shavit) involved a failed stage separation. Etc. - Ed Kylethe liquied failures are surivable. The rest of the world is not a good database. Spacex and India are not in the same population as the US and Russia wrt spacelaunch
edkyle99 - 13/7/2006 11:04 AMI don't breath until wheels stop on the runway. Fair to mention, by the way, that liquid boosters fail more often than solids. Just look at the recent GSLV failure from India, for one example. GSLV has a powerful solid booster core with four strap-on liquid boosters. The solid worked fine. One of the liquids failed. There have been three launch failures this year so far, in 31 attempts. All of the failures involved liquid propulsion systems. Last year there were three failures in 55 attempts. All of the failures were liquids. Three of the four failures in 2004 were liquids. The solid rocket failure (Shavit) involved a failed stage separation. Etc. - Ed Kyle
zinfab - 13/7/2006 1:07 PMWould this group agree that the ATK solid rocket boosters are the most reliable rockets currently available?If we switch to EELV, will they cut the size/mass of the CEV EVEN MORE, or redesign them to carry more (MORE development costs)?
Jim - 13/7/2006 12:01 PMIt was a successful launch and the mission was completed as far as a launch vehicle. And that is the official ruling.
rumble - 13/7/2006 10:11 AMHow serious is this "chatter?" Based on what I understand (which could be incorrect), I would assume a kerosene 1st stage (RD-180) for the core stage would need a beefy second stage. The current plan for the 2nd stage/EDS doesn't seem to be this.Could an RD-180 based 1st stage truly be a replacement for the capability of the RS-68 CaLV core stage, or would other vehicle changes be necessary to accompany this?
edkyle99 - 13/7/2006 1:15 PMQuoteJim - 13/7/2006 12:01 PMIt was a successful launch and the mission was completed as far as a launch vehicle. And that is the official ruling.Official ruling? There are officials? :-)Whatever it was "ruled", it didn't look like a good launch to me. - Ed Kyle
Jim - 13/7/2006 1:18 PMQuoteedkyle99 - 13/7/2006 1:15 PMQuoteJim - 13/7/2006 12:01 PMIt was a successful launch and the mission was completed as far as a launch vehicle. And that is the official ruling.Official ruling? There are officials? :-)Whatever it was "ruled", it didn't look like a good launch to me. - Ed KyleStuff comes off every launch vehicle.
bad_astra - 13/7/2006 12:31 PMEd, if the columbia stack had been a sidemounted cargo pod a-la Polyus, the payload would have survived, therefore it was a good launch.
edkyle99 - 13/7/2006 2:45 PMQuoteJim - 13/7/2006 1:18 PMQuoteedkyle99 - 13/7/2006 1:15 PMQuoteJim - 13/7/2006 12:01 PMIt was a successful launch and the mission was completed as far as a launch vehicle. And that is the official ruling.Official ruling? There are officials? :-)Whatever it was "ruled", it didn't look like a good launch to me. - Ed KyleStuff comes off every launch vehicle.The orbiter is the part fo the LV and it performed its part of launch (SSME's, avionics) . Any payload that would have deployed form the shuttle, would have done so and with success. The orbiter failed as a reentry vehicle because it's TPS wasn't robust enough (a design flaw). Foam coming off the ET is not flaw, it is happens with all vehicle that use foam. NASA and the USAF classify it as a entry failureI look at the issue from an insurance adjustor's point of view. A successful launch is one that delivers a payload, *unscathed*, to the contracted orbit. The shuttle launch stack successfully delivered its orbiter "payload" to the proper orbit, but it was most certainly not unscathed. STS-107 delivered damaged goods (the orbiter Columbia with a fatal hole in its wing's leading edge) to orbit. If this were a commerical type launch, with one company owning the launch vehicle and another owning the orbiter (as payload), an adjustor would ascribe the failure to the launch vehicle, and a claim would be promptly filed. - Ed Kyle
edkyle99 - 13/7/2006 2:50 PMQuotebad_astra - 13/7/2006 12:31 PMEd, if the columbia stack had been a sidemounted cargo pod a-la Polyus, the payload would have survived, therefore it was a good launch.STS-107/Columbia was not Energia/Polyus. Two different animals. - Ed Kyle
hyper_snyper - 13/7/2006 3:35 AMI think the SRBs were one of the main drivers to the architecture we have today. Whether thats a good thing or bad thing I don't know. If you're going to have a RS-68 first stage you might as well just mod a Delta IV to do the job, IMO.
Jim - 13/7/2006 9:13 PMThe orbiter is the part fo the LV and it performed its part of launch (SSME's, avionics). It isn't the payload. Any payload that would have deployed form the shuttle, would have done so and with success. The orbiter failed as a reentry vehicle because it's TPS wasn't robust enough (a design flaw). Foam coming off the ET is not flaw, it is happens with all vehicle that use foam, trying to fix it is a crutch (that's why there will always be post flight inspections). the orbiter wasn't properly designed for the flight environment Harsh as it sounds this was a reuse issue.NASA and the USAF classify it as a entry failure
Jim - 13/7/2006 2:13 PMQuoteedkyle99 - 13/7/2006 2:45 PMI look at the issue from an insurance adjustor's point of view. A successful launch is one that delivers a payload, *unscathed*, to the contracted orbit. The shuttle launch stack successfully delivered its orbiter "payload" to the proper orbit, but it was most certainly not unscathed. STS-107 delivered damaged goods (the orbiter Columbia with a fatal hole in its wing's leading edge) to orbit. If this were a commerical type launch, with one company owning the launch vehicle and another owning the orbiter (as payload), an adjustor would ascribe the failure to the launch vehicle, and a claim would be promptly filed. - Ed KyleThe orbiter is the part fo the LV and it performed its part of launch (SSME's, avionics). It isn't the payload. Any payload that would have deployed form the shuttle, would have done so and with success. The orbiter failed as a reentry vehicle because it's TPS wasn't robust enough (a design flaw). Foam coming off the ET is not flaw, it is happens with all vehicle that use foam, trying to fix it is a crutch (that's why there will always be post flight inspections). the orbiter wasn't properly designed for the flight environment Harsh as it sounds this was a reuse issue.NASA and the USAF classify it as a entry failure
edkyle99 - 13/7/2006 2:45 PMI look at the issue from an insurance adjustor's point of view. A successful launch is one that delivers a payload, *unscathed*, to the contracted orbit. The shuttle launch stack successfully delivered its orbiter "payload" to the proper orbit, but it was most certainly not unscathed. STS-107 delivered damaged goods (the orbiter Columbia with a fatal hole in its wing's leading edge) to orbit. If this were a commerical type launch, with one company owning the launch vehicle and another owning the orbiter (as payload), an adjustor would ascribe the failure to the launch vehicle, and a claim would be promptly filed. - Ed Kyle
yinzer - 13/7/2006 10:03 PMThe lack of graceful emergency thrust termination can give higher LOC numbers with very detailed modeling - it makes aborts much more dynamic events. The numbers are small enough that it's hard to make any sort of statistical judgement, and the probabilistic risk assessments made to date for the shuttle have all been wildly optimistic.In any case, according to NASA Watch, MSFC is considering going to the RD-180 for the CaLV core stage. And as long as they're doing that, they might as well go to a 2 RD-180 core stage for the CLV. If they call it Atlas Phase 2 there's already a bunch of paperwork and promotional material available. NASA Watch also says that there's consideration of dumping the CLV for an EELV because the CLV is having trouble lifting the CEV and is costing way more than was expected.
Avron - 13/7/2006 11:21 PMSolids vs "mature liquid systems" ( LOX driven systems - assumption)... lets up the statistical numbers... if x is the number of STS flights, then 2x is the number of SRB's used in the real world, but in the same time there are 3X SSME in these flights, with one failure to one SRB failure... based on this for US based manrated LV's in the last quarter century.. Clearly the "mature liquid systems" are ahead of the game.. and if you add in the time of operation, under flight load conditions... SRB just don't come close in that numbers game...its all MTFB.. reliability numbers are as a WAG an order of magnitude higher...