brettvs@blake.u.washington.edu (Brett Vansteenwyk) (11/11/90)
Not long ago it was noted that the first of Endeavour's engines had arrived at KSC. Some mention was made that these engines were "new and improved". I was hoping that more would be said to elaborate on this, but I will go ahead and pound out a few questions... [1].Are these new engines useable in the older shuttles? It would seem important considering the considerable swapping of engines and their parts that seems to go on in the refurbishment process. [2].Are these engines part of a more "mature" system? In other words, has there been a batch of changes made to the manufacture/design of these "new" engines that will improve their servicability and ease of refurbishment? [3].(Slight rehash from [2]). While the SSME's have not been a particular saftety problem (in hindsight, at least relative to the SRB's), their turn- around launch to launch has been a nightmare for costs--so much of each engine needs to be rebuilt. This seems to stem from the fact that this design pushed the envelope for efficiency and thrust to weight ratio. This engine has been in use for almost 10 years, and it would seem that it could be classified as a "mature" system by now--a learning curve with subsequent reduction in refurbishment costs as well as a more reliable engine. Is there evidence to indicate that this has happened? If not so far, will these new engines allow hope for that to happen in the future? [4].Whenever I see any discussion about new launcher development, I never, or almost never see any suggestion to using the SSME's, nor do I see any indication of an engine derived from SSME technology. The tendency is to discuss systems originating 25 or even 30 years back. I am assuming that the SSME was the most recent major engine development. Has all the time and talent spent to make the SSME work been wasted on what is now considered an evolutionary dead-end? While it may seem disconcerting, it seems where the evidence is pointing. [5].If not the evolutionary dead-end as postulated in [4], could there be an SSME derivative for an expendable launcher, or a restartable version for purposes similar to the Saturn 3rd stage system? (All in all, is it meaningful to think of derivatives of this technology since this is the newest technology by far?) Just some random thoughts. --Brett Van Steenwyk
henry@zoo.toronto.edu (Henry Spencer) (11/14/90)
In article <10948@milton.u.washington.edu> brettvs@blake.u.washington.edu (Brett Vansteenwyk) writes: >Not long ago it was noted that the first of Endeavour's engines had arrived >at KSC. Some mention was made that these engines were "new and improved". Don't read too much into this. There has been no major design change, just a bunch of small incremental improvements. >[1].Are these new engines useable in the older shuttles? ... Yes. >[2].Are these engines part of a more "mature" system? In other words, has >there been a batch of changes made to the manufacture/design of these "new" >engines that will improve their servicability and ease of refurbishment? That's the hope. Considering the magnitude of the failure to meet the original targets in these areas, there is room for a lot of improvement. >This engine has been in use for almost 10 years, and it would seem >that it could be classified as a "mature" system by now--a learning curve >with subsequent reduction in refurbishment costs as well as a more reliable >engine. Is there evidence to indicate that this has happened? ... Well, maybe some. The thing you learn from the learning curve in this case is really "these things will never be wonderful without major redesign". >[4].Whenever I see any discussion about new launcher development, I never, >or almost never see any suggestion to using the SSME's, nor do I see any >indication of an engine derived from SSME technology. The tendency is >to discuss systems originating 25 or even 30 years back. I am assuming >that the SSME was the most recent major engine development. Has all the >time and talent spent to make the SSME work been wasted on what is now >considered an evolutionary dead-end? ... Very nearly. The Japanese decided to adopt a similar approach (although a from-scratch design) for their H-2 booster, and are now regretting it. Most everyone else proposing new launchers wants to use less ambitious and more dependable engines, either old ones or new developments. The SSME concept wasn't bad in principle, and maybe it is the wave of the future if you're patient enough, but making it work well seems to be exceedingly difficult today. Certainly the SSME itself shows no signs of ever becoming particularly cheap. >[5].If not the evolutionary dead-end as postulated in [4], could there be >an SSME derivative for an expendable launcher... The definitive Shuttle C proposal wanted to use life-expired shuttle engines in an expendable launcher. The Hughes/Boeing Jarvis proposal also used expendable SSMEs, after they tried very hard to come up with a viable scheme for reviving the F-1 and J-2 and couldn't make it work. The SSME is just too expensive to be a good expendable engine, though. -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry
dlbres10@pc.usl.edu (Fraering Philip) (11/14/90)
In article <1990Nov13.190528.5893@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
HS>in an expendable launcher. The Hughes/Boeing Jarvis proposal also used
HS>expendable SSMEs, after they tried very hard to come up with a viable
HS>scheme for reviving the F-1 and J-2 and couldn't make it work. The SSME
HS>is just too expensive to be a good expendable engine, though.
?
I was under the impression that the reason Jarvis was not built,
in either 'incarnation,' was because of political reasons. After all,
isn't the shuttle the most capable vehicle ever built?
Philhenry@zoo.toronto.edu (Henry Spencer) (11/14/90)
In article <DLBRES10.90Nov13163343@pc.usl.edu> dlbres10@pc.usl.edu (Fraering Philip) writes: >HS>in an expendable launcher. The Hughes/Boeing Jarvis proposal also used >HS>expendable SSMEs, after they tried very hard to come up with a viable >HS>scheme for reviving the F-1 and J-2 and couldn't make it work. The SSME >HS>is just too expensive to be a good expendable engine, though. > >I was under the impression that the reason Jarvis was not built, >in either 'incarnation,' was because of political reasons... Well, sort of. The fundamental problem was the lack of customers. Hughes/Boeing was perfectly happy to foot the development bill, given enough "launch customers" [pun unintentional] to justify it. But the government wasn't interested, in the end. A contributing factor, probably, was excessive reliance on shuttle technology that was under the political control of people who weren't keen on the idea. Even the original F-1/J-2 concept used tankage based on the shuttle ET. -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry
gregc@cimage.com (Greg Cronau) (11/14/90)
In article <1990Nov13.190528.5893@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: > >The definitive Shuttle C proposal wanted to use life-expired shuttle engines >in an expendable launcher. The Hughes/Boeing Jarvis proposal also used >expendable SSMEs, after they tried very hard to come up with a viable >scheme for reviving the F-1 and J-2 and couldn't make it work. The SSME >is just too expensive to be a good expendable engine, though. I can understand why reviving the Saturn program would be damn near impossible, but what problems were encountered with reviving just the F-1 engine program? gregc@cimage.com
henry@zoo.toronto.edu (Henry Spencer) (11/15/90)
In article <1990Nov14.071003.24567@cimage.com> gregc@dgsi.UUCP (Greg Cronau/10000) writes: >>... The Hughes/Boeing Jarvis proposal also used >>expendable SSMEs, after they tried very hard to come up with a viable >>scheme for reviving the F-1 and J-2 and couldn't make it work... > >I can understand why reviving the Saturn program would be damn near impossible, >but what problems were encountered with reviving just the F-1 engine program? Basically, a subset of the problems with reviving the Saturn. The hardware was long out of production and quite a bit of tooling and knowledge about production processes and operations had gotten lost. It would have required extensive re-engineering and re-testing to produce flight-qualified engines. (Some people may not realize just how difficult it is to duplicate a modern high-tech product without full manufacturing data. The problem is not that you can't figure out what shape the turbopump blades (for example) should be, but that it's very hard to reverse-engineer the exact heat-treatment process used to make them durable enough. Especially if the subcontractor who made them has gone out of business and all records have been lost.) People who were involved tell me that Boeing tried *very* hard to use the old engine designs, to avoid the SSMEs and SRBs, but just could not come up with a plan that looked economically viable. -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry
megazone@wpi.WPI.EDU (MEGAZONE 23) (11/15/90)
In article <1990Nov14.071003.24567@cimage.com> gregc@dgsi.UUCP (Greg Cronau/10000) writes: >In article <1990Nov13.190528.5893@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >>The definitive Shuttle C proposal wanted to use life-expired shuttle engines What is the status of the Shuttle-C program now? >I can understand why reviving the Saturn program would be damn near impossible, >but what problems were encountered with reviving just the F-1 engine program? I heard that NASA 'lost' the plans to the F1 and that the private companies that are interested in the engine are going through the long a tiring process of reverse engineering one. Seems the plans were lost during the early stage of shuttle development, around the time officials were looking at dumb boosters again. hmmmm. ############################################################################### # "Calling Garland operator 7G," EVE Email megazone@wpi.wpi.edu # # MEGAZONE, aka DAYTONA, aka BRIAN BIKOWICZ Bitnet Use a gateway. Sorry. # ###############################################################################
henry@zoo.toronto.edu (Henry Spencer) (11/16/90)
In article <1990Nov15.024856.24199@wpi.WPI.EDU> megazone@wpi.WPI.EDU (MEGAZONE 23) writes: >>>The definitive Shuttle C proposal wanted to use life-expired shuttle engines > >What is the status of the Shuttle-C program now? Stalled, pending funding. It doesn't help that a whole lot of irrelevancies got loaded in on top of the basic Shuttle C design in the funding plan. It would almost make you think that somebody didn't want it to succeed... -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry
gwh@monsoon.Berkeley.EDU (George William Herbert) (11/16/90)
In article <1990Nov15.173318.7370@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >>What is the status of the Shuttle-C program now? > >Stalled, pending funding. It doesn't help that a whole lot of irrelevancies >got loaded in on top of the basic Shuttle C design in the funding plan. It >would almost make you think that somebody didn't want it to succeed... Various people are doing work on it. Even Martin Marietta is working on one (the four-engine 100-ton to LEO shuttle Z). But, it isn't getting funding. Despite being a great way to put Freedom up in one chunk 8-) [well, with the current design tossout, maybe not, ...] == George William Herbert == **There are only two truly infinite things,** == JOAT for Hire: Anything, == * the universe and stupidity. And I am * =======Anywhere, My Price======= * unsure about the universe. -A.Einstein * == gwh@ocf.berkeley.edu == ********************************************* == ucbvax!ocf!gwh == The OCF Gang: Making Tomorrow's Mistakes Today
brettvs@blake.u.washington.edu (Brett Vansteenwyk) (11/16/90)
My impression was (especially from reading Feynman's book) that the SSMEs were virtually rebuilt after each launch--the component parts going into a system of inspection and repair such that when a given engine was rebuilt, many of the pieces in the new build came from other engines that were also in the rebuild process at the time--the original engine's parts by and large would not find one another again, except for statistical chance. It seemed that each engine was disassembled into some pretty small pieces, where they could be inspected, repaired, etc., and that the rebuild was as involved as building a new engine. Cracked turbine blades were a big item here. Anyway, this is what I referred to as the "enormous refurbishment cost". If this sort of undertaking is no longer as extensive as I have described, then it would seem that these engines have come quite a way, and would be quite happy to hear of it. I am curious as to how much of a design difficulty it is to have an engine operate (well or otherwise) at both sea level and in the vacuum (just a matter of ambient pressure or much more?). If this is a heavy constraint, why light the SSMEs at sea level at all when it would seem that you could replace that thrust (1/6 or so of the total) by adding another booster and then lighting them high up at, say, the booster separation? I realize that there is a certain reluctance to tacking on an SRB, but if LRBs get developed, could this become a viable option? By the way, I remember that there is some consideration (or ongoing effort) to adapting the RL-10 to operate at sea level. Is this a good example of this sort of design "difficulty"? [Really random question] Aside from the weight consideration, how close do automobile turbochargers come to the operating conditions of their counterparts (with a stretch of the imagination) in some of the lower performance rocket engines? --Brett Van Steenwyk
tohall@mars.lerc.nasa.gov (Dave Hall (Sverdrup)) (11/17/90)
In article <1990Nov14.071003.24567@cimage.com>, gregc@cimage.com (Greg Cronau) writes... > >I can understand why reviving the Saturn program would be damn near impossible, >but what problems were encountered with reviving just the F-1 engine program? In addition to lost documentation and tooling costs, two areas I am aware of are: 1) Air pollution. The F-1 burns LOX and kerosene, producing a smoky hydrocarbon exhaust. Not popular with environmentalists, especially in S. California where the Rocketdyne test labs are located. 2) F-1 production test facilities were located in the San Fernando valley (turbopumps at Rocketdyne/Santa Susana) and Edwards AFB (full-up engine tests). These facilities are way past the inactive stage - they have been either torn down or become completely derelict. You are talking 100's of millions of dollars (IMHO) to refurbish them.
henry@zoo.toronto.edu (Henry Spencer) (11/17/90)
In article <11236@milton.u.washington.edu> brettvs@blake.u.washington.edu (Brett Vansteenwyk) writes: >I am curious as to how much of a design difficulty it is to have an engine >operate (well or otherwise) at both sea level and in the vacuum ... It's not an enormously big deal, but it is a nuisance. Ignoring some details, one gets maximum thrust out of a given exhaust stream if it exits the nozzle at roughly ambient pressure. This means that a nozzle optimized for high altitude will be a good bit longer than a sea-level nozzle, to give the gas more expansion. An underexpanded nozzle, with the gas exiting at higher than ambient, results in some loss of thrust. A badly overexpanded nozzle causes the gas flow to break away from the nozzle wall before reaching the end, which causes all manner of nasty turbulence and problems of various kinds. The SSME nozzles are in fact mildly overexpanded for use at sea level, for the sake of performance at high altitude, but not enough to cause major trouble. Multiple stages, with upper stages ignited only at high altitude, offer somewhat of a way out of this. The first stage is still a compromise, because it finishes its burn in much thinner air than it started in, but the upper stages can use fairly uncompromised high-altitude nozzles. People have explored more devious schemes, like variable-length nozzles, but no real use has been made of them yet. >... If this is a heavy constraint, why light >the SSMEs at sea level at all ... One very important practical reason is that the #1 time for engine trouble is at ignition. Lighting the SSMEs on the pad means that the more benign kinds of engine failures simply cause a pad abort. There may also have been some hope that gimballing the SSMEs would suffice for control, and the SRBs wouldn't need gimballed nozzles, although in fact that didn't pan out. >By the way, I remember that there is some consideration (or ongoing effort) >to adapting the RL-10 to operate at sea level. Is this a good example of >this sort of design "difficulty"? In principle, all you need is a shorter nozzle, although you have to think about things like the effect on the cooling system. There may be some issues in ignition, too. -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry
iiitsh@cybaswan.UUCP (Steve Hosgood) (11/19/90)
>>but what problems were encountered with reviving just the F-1 engine program? > >In addition to lost documentation and tooling costs, two areas I am aware of >are: > For that matter, why would anyone want to revive the F1? OK, so maybe it should never have been scrapped, but if the US suddenly needed a big F1 type engine, they could just go and buy one off the Russians - or the ESA if the former option is still too unpalateable to the powers-that-be in the US... It would be better to look ahead - not back. And in future, don't scrap known technology just because you want to move ahead. Someone (Henry probably) once pointed out that the existing shuttle could be massively improved (and lightened) by use of newer computers, newer engines etc etc. When asked though, NASA insisted on only more of what it already had - even for building Endeavour. *That* is not the way forward. Steve | WALES: "Land of Song iiitsh@pyr.swan.ac.uk | and Rugby^H^H^H^H^H ..or in Britain, where we drive on the other side:| Ice Hockey" iiitsh@uk.ac.swan.pyr |
nak@cbnews.att.com (Neil A. Kirby) (11/19/90)
In article <1990Nov16.175907.18177@eagle.lerc.nasa.gov>, tohall@mars.lerc.nasa.gov (Dave Hall (Sverdrup)) writes: > > 2) F-1 production test facilities were located in the San Fernando valley > (turbopumps at Rocketdyne/Santa Susana) and Edwards AFB (full-up > engine tests). These > facilities are way past the inactive stage - they have been either torn > down or become completely derelict. You are talking 100's of millions of > dollars (IMHO) to refurbish them. Out of curiousity, would the test area at Stennis Space Center (in Mississippi) be able to do some of the testing? Stennis tests every SSME, and the test stands for the Saturn V stack elements are still there. Neil Kirby ...att!archie!nak
john@newave.UUCP (John A. Weeks III) (11/20/90)
In <1990Nov16.175907.18177@eagle.lerc.nasa.gov> tohall@mars.lerc.nasa.gov: > In <1990Nov14.071003.24567@cimage.com>, gregc@cimage.com (Greg Cronau): > > I can understand why reviving the Saturn program would be damn near > > impossible, but what problems were encountered with reviving just the > > F-1 engine program? > 2) F-1 production test facilities were located in the San Fernando valley > (turbopumps at Rocketdyne/Santa Susana) and Edwards AFB (full-up engine > tests). These facilities are way past the inactive stage - they have been > either torn down or become completely derelict. On a related note, I recently toured the NASA Stines Center in Mississippi where NASA tests & certifies the shuttle engines. The buildings that housed the test facilities for the Saturn engines are still there, but they have long since been converted for other uses. The second stage test building now houses a rather deep water tank that is used to test sensors used in ocean research. The only thing that appears to be left from Saturn and Apollo are some blast staines on the concrete. -john- -- =============================================================================== John A. Weeks III (612) 942-6969 john@newave.mn.org NeWave Communications ...uunet!rosevax!bungia!wd0gol!newave!john ===============================================================================
loren@dweasel.llnl.gov (Loren Petrich) (11/20/90)
In article <2154@cybaswan.UUCP> iiitsh@cybaswan.UUCP (Steve Hosgood) writes: > >Someone (Henry probably) once pointed out that the existing shuttle could >be massively improved (and lightened) by use of newer computers, >newer engines etc etc. When asked though, NASA insisted on only more >of what it already had - even for building Endeavour. > >*That* is not the way forward. True, but this is equipment that has to work EXTREMELY reliably, all because of the people on board. So that's why NASA has stuck to its older, clumsier hardware. I guess that's why unmanned spacecraft will still be necessary -- there is less to lose with failure. I know someone elsewhere in LLNL who knows of a Lab project that is to be sent up on a Pegasus rocket. To LEO, a Pegasus can send up about 500 kg, if I remember correctly. Furthermore, there is only a six-month wait for the Pegasus, as opposed to a three-year wait for the Shuttle. He also told me that, because it was unmanned, they could design it closer to performance limits. Thus, they could use 1/2 burst pressure in one place, as opposed to 1/5 burst pressure for a Shuttle payload. Currently, with about $6m per Pegasus and 500 kg to LEO, it works out to $1200 per kilo -- more than competitive with the Shuttle. $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ Loren Petrich, the Master Blaster: loren@sunlight.llnl.gov Since this nodename is not widely known, you may have to try: loren%sunlight.llnl.gov@star.stanford.edu