gandalf@pro-canaveral.cts.com (Ken Hollis) (11/30/90)
Greetings and Salutations: >From: henry@zoo.toronto.edu (Henry Spencer) >>... because they COULD be made complex. Computer systems & control >... Complexity for complexity's sake is a bug, not a feature. >Its only function is to keep lots of engineers and technicians employed, >which drives costs up and up and up. ...and when Canada starts contributing to the Space program, we will be HAPPY to hear your opinion on cost effectiveness... >>Pratt & Whitney Turbopumps : Longer life expectancy between changeouts, > >...The P&W turbopumps, at the moment, are a prototyping exercise only. > There is no commitment to *ever* use them as flight hardware. There are plans for the incorporation into flight hardware, of course contingent on the acceptance testing schedules at John C. Stennis Space Center (SSC) for ?Early 1991? on ME0213. I don't think ANYBODY would commit to a part on the promise that it would work, especially NASA. >>Large throat MCC (Main Combustion Chamber) > >Recent progress on this is essentially zero. And again, there is *no* >commitment to ever use it for flight hardware; it is being treated as The Large Throat has been hotfired on engine 0208 (Development Engine) for 310 Seconds. This modification lowers turbine temps, pump discharge pressure & preburner chamber pressure to allow normal 109% operation ( or higher). It takes years for modifications to get approved, you don't want to rush something through & screw something else up. > >Sorry, I don't give credit for a capability that is not being used because >of fears that it is unsafe. They don't run the SSMEs at 109% any more. On the test stands at SSC, engines ME2010 & ME2014 went through a full Performance Certification Cycle. The wear on the components was more than expected, while not dangerous, and was not considered to be an effective (or particularly good) use of the engines. the engines downgraded back to 104% nominal usage. While you are correct that the engines are not run during a nominal flight at 109%, the flight engines are still tested with short bursts of up to 113% - 117%. Development engines are hotfired at 111%. If you look up the abort scenarios, there is a requirement for the engines to run at 109% for an RTLS. >-- >"I'm not sure it's possible | Henry Spencer at U of Toronto Zoology >to explain how X works." | henry@zoo.toronto.edu utzoo!henry > I consider this to be "work" and "progress", but since you didn't define the above, I am sure you will decide for yourself... Ken Hollis ProLine: gandalf@pro-canaveral Internet: gandalf@pro-canaveral.cts.com UUCP: crash!pro-canaveral!gandalf
francis@cs.ua.oz.au (Francis Vaughan) (11/30/90)
This discussion about redesign of parts of the SSMEs makes me rather curious about a few things. So far we have seen a new engine controller, new turbo pumps, and a new main combustion chamber. I strikes me probably rather naively, that we are seeing a large part of the effort needed to redesign any engine. How different in effort has the upgrading of the SSME been compared to that almost holy grail of discussion, the retooling for an F-1 engine? It just seems that, if one was to start with the premise that an F-1 mark 2 was the target very similar ideas and engineering would be used. We know all of the BASIC design of the F-1. I.E. we know exactly what dimensions all of the parts are, and in particular, how to fit togther subassembies. Surely there exists broad engineering specifications for the F-1 even if the blueprints and tooling is lost. Things like pressures, flowrates, enough to understand how a subassembly should work if not enough to duplicate the subassembly. Just imagine that instead of building a new set of turbopumps for the SSME we had the same design brief for the F-1? I suspect that it would be a similar task. There is no necessity to understand incredibly detailed and arcne knowledge about how the rest of the engine was fabricated, just more global knowledge about how the engine works and how the subsystems fit. Same goes for the combustion chamber, engine controller, and the remainder. Remember we have a proven overall design. We know that the F-1 worked. In principle the old F-1 plus new turbopumps would fly, same after a new cumbustion chamber etc. Suddenly we have a new improved MANUFACTURABLE F-1. What is left? Naively again it seems that what is left is: plumbimg, bell, startup bits, and vectoring bits. These I can't help feeling are not as scary as building the turbopumps. I can't help feeling that the effort expended on upgrades to the SSME would have got us half way to an F-1 Mk II. If such an engine were produced it could replace the SRBs on the shuttle, with the money for the advanced SRB going into the design of the rest of the new booster. It could also have been used as the basis of a new big unmanned rocket that people keep clamoring for. Its not that I am advacating the this is what we should do, rather lament that it might have been. The money has already been spent. Probably not enough pork in the right barrels anyway. I will admit that I have a soft spot for the F-1 (I still have a set of big photos I took at KSC of one on my wall). It is an awsome bit of engineering. Its not that its big, rather that when one looks closely at it it just seems to small. All that force directed through such a relatively small structure. (I have said before that a kerosene/LOX engine would still look fantastic when launched too :-) Francis Vaughan.
hwt@bwdlh490.BNR.CA (Henry Troup) (12/01/90)
In article <5973@crash.cts.com>, gandalf@pro-canaveral.cts.com (Ken Hollis) writes: |>...and when Canada starts contributing to the Space program, we will be HAPPY |>to hear your opinion on cost effectiveness... Can we have the arms back, then? Henry Troup - BNR owns but does not share my opinions | The .signature is the P.O. Box 3511, Stn. C. Ottawa, Ontario, Canada K1Y 4H7| lowest form of humour uunet!bnrgate!hwt%bwdlh490 HWT@BNR.CA +1 613-765-2337 |
henry@zoo.toronto.edu (Henry Spencer) (12/01/90)
In article <5973@crash.cts.com> gandalf@pro-canaveral.cts.com (Ken Hollis) writes: >...and when Canada starts contributing to the Space program, we will be HAPPY >to hear your opinion on cost effectiveness... That's good to hear, since Canada has been contributing -- in modest ways -- to the US space program ever since Project Mercury. If you don't know how, I suggest you do some reading, which you might find educational. :-) >>...The P&W turbopumps, at the moment, are a prototyping exercise only. >> There is no commitment to *ever* use them as flight hardware. > >There are plans for the incorporation into flight hardware... Assuming they test out all right, when are they first scheduled to fly? My understanding is that they aren't. If they test out all right, then NASA will *think* about the possibility of flying them someday. Ditto for the large-throat chamber. There is no specific schedule or commitment. At least one review board -- I think it was the NRC panel -- has openly criticized NASA for this "maybe someday" attitude to important upgrades. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry
keithley@applelink.apple.com (Craig Keithley) (12/01/90)
In article <5973@crash.cts.com> gandalf@pro-canaveral.cts.com (Ken Hollis) writes: > >... Complexity for complexity's sake is a bug, not a feature. > >Its only function is to keep lots of engineers and technicians employed, > >which drives costs up and up and up. > > ...and when Canada starts contributing to the Space program, we will be ^^^ Please speak for yourself. I enjoy Henry's comments and insights about the space program. And the fact he is (or isn't) Canadian has absolutely nothing to do with his ability to express opinions about damn near anything. Craig Keithley, Apple Computer keithley@applelink.apple.com ITS NOT MY FAULT! [standard disclaimers apply!]
mae@vygr.Eng.Sun.COM (Mike Ekberg, Sun {DSGG.DGDO.Mid-Range Graphics.Egret(GS)} MS 8-04) (12/01/90)
I am sort of curious on the criteria NASA uses to determine
if an upgrade is worth doing. I naively assume this is "merely"
an exercise in the cost of research/development/test vs. the
long run cost savings.
So they would need estimates for things like the useful life
of a shuttle (ohoh, that's a touchy one {:->), depreciation,
test costs, research costs, price of pork barrels, etc.
--
# mike (sun!mae), M/S 8-04
"The people are the water, the army are the fish" Mao Tse-tung