Path: utzoo!attcan!uunet!cs.utexas.edu!samsung!umich!sharkey!cfctech!teemc!fmeed1!cage From: cage@fmeed1.UUCP (Russ Cage) Newsgroups: sci.space Subject: Re: You Can't Expect a Space Station to be Cheap (if NASA builds it) Summary: Radley says some *very* interesting (and questionable) things. Message-ID: <8634@fmeed1.UUCP> Date: 2 Nov 90 18:27:27 GMT References: <6781@hub.ucsb.edu> <9010282110.AA00719@iti.org> <6930@hub.ucsb.edu> Reply-To: russ@m-net.ann-arbor.mi.us (Russ Cage) Organization: Ford Motor Co., Electronics Div., Dearborn, MI Lines: 174 First, pardon for the previous near-flame. In article <6930@hub.ucsb.edu> 3001crad@ucsbuxa.ucsb.edu (Charles Frank Radley) writes: >+Second of all, the LLNL contractors on this DO have a good track >+record in large aerospace systems. > >So do the Freedom contractors....... Then the question to be asked is, does this make a difference? Where are the actual decisions being made? To answer that, look at all the original proposals for the space station. They looked almost identical, regardless of contractor. NASA had already decided what the design would be, and thus what the "winning" design could look like; the contractors had no say. Given that the drive behind the design for Fred came from NASA and not Boeing, it stands to reason that Boeing's track record in aerospace systems will not assist in producing a working product; their ingenuity and know-how has been subordinated. It is not an engineering problem, it is a management problem. LLNL could probably produce just as good and cheap a product using Boeing as McD-D, again because of management philosophy. (But it would mean fewer bucks for Boeing. Then again, there is the possibility of repeat business if it was cheap enough; ESA might buy one, especially if it could go up on Ariane.) >Don't you think LLNL will go through similar cost increases as >reality starts to dawn, and the magnitude of the task is truly >appreciated ? "Reality dawning" assumes that some difficult-to-rectify mistakes have been made. Fred is going through this with the EVA problem. I think it is a bit presumptuous to assume that LLNL will make the same mistakes as today's NASA; they're more like Von Braun's NASA. >> Proposing untried NiH batteries which have no advantage over > >existing ones; >+ These batteries provide more power for less weight. This >+results in cost savings which most people think is an advantage. > >proposing untried amorphous silicon cells with > >dubious qualification prospects and admitting conventional >> cells woulBd be just as good and less risky; > >But the NiH and solar celss are not space qualified, and they >underestimate the qual costs, which could wipe out the saving. >And they may never pass qual. It could be a valid R & D program, >I simply object to LLNL trying to sell it as being cheap and off >the shelf. If LLNL has allowed enough extra in the launch-weight budgets for replacements, the premature deterioration of the batteries or solar panels would be dealt with by replacing them. The older, heavier, previously-qualified hardware could be used for such replacements. If replacement is not required, a newer, lighter, cheaper technology is qualified by default and at a cost savings. >No it is worse, if they fail and Freedom is cancelled, we waste >decades, it will take that long to rebuild a manned space >program. So put Fred on hold. It's certain that the time can be used to fix some of the nasty design problems (excessive EVA, etc.) which have surfaced. The more of these which are fixed before metal is bent, the better and cheaper the result will be if it turns out that it is indeed the better choice. >Oh come on, the Delta is an unmanned ELV, there are no manned >spacecraft designed to fly on delta. And developing a new >manned spacecraft is not cheap. Don't tell me that has been >factored into the cost too. Perhaps we should buy Soyuz's, they're certainly cheap and it is proven that useful work can be done with them. We don't need to mate them with a Delta, we can buy SL-4's. >But again, Titan is expensive, no cheaper than shuttle. Don't >tell me they have included costs of Titans in their plan. This >really is getting very far fetched. Allen quoted a number of an additional $500 million to use Titan IV instead of HL-Delta. Do you have a problem with this? (This number must have included several launches.) >Wrong again. Titan is no cheaper than Shuttle. Delta is too >small too launch the LLNL package, so requires a complete >redesign which cancels out the launch cost saving. Titan-IV >with the Centaur< costs as much as Shuttle. And if LLNL has designed to launch in one piece or several, they would not require a re-design to change launchers. (Allen: have they?) >A single Titan-IV launch gives you a tiny space station. More >like a MIR than a Freedom. MIR is a lot cheaper than LLNL. >The whole point of Freedom is its size and capability. LLNL gives >all that away. Mister Radley, it must have been explained to you that the LLNL station is INFLATABLE. It is not launched as a number of rigid tin cans, it ends up at a multiple of its original size. The final station is many times the volume of the payload fairing in which it is launched; this allows it to be sent up in one launch, with one launch risk. This is the big advantage over Fred. Why do you persist in ignoring this crucial distinction? (BTW, if we adopt an extremely conservative working strength of 7500 PSI for the Kevlar fibers and a density of 2 gm/cc, the weight of an entire 15 foot diameter by 60 foot long segment is only 7944 lbs for the walls, and the volume is only 64 cubic feet. I'm sure I have radically under-stated the strength of Kevlar; I assumed UTS of 30 KPSI and a safety factor of 4. This shows some of the potential for space and weight savings.) >I will not dispute those probabilities, other people arrive at >different numbers. The point of failure rate predictions like >that is as an inspiration to work on the causes and fix them. This is another curious statement, Allen. The man states that point-of-failure predictions are an inspiration to work on the cause. In this case, the cause is the unreliability of the launcher (Shuttle) and the dependence of the station's orbit on the launch schedule (too many slips and it re-enters). Despite this, it was Congress which told NASA to consider launchers other than Shuttle to assist with launching Freedom, rather than NASA or Boeing suggesting it to Congress. Mister Radley, are you sure you are doing your job properly? Are you prevented from doing so by the project management, or are these oversights and omissions the fault of the workers? Why haven't you considered using alternate launchers? >That is why the number was generated. You don't just close your >eyes and pray...! Reliability predictions are design tools, not >forecasts of doom. Again, an odd statement. It has been shown that another launch moratorium such as the one following Challenger would cause the re-entry of Fred, er, Freedom. Yet management has closed its eyes and prayed that this will not happen. Tell us, Charles, just what are NASA/Boeing planning to do to prevent the re-entry of Freedom in the case of the Shuttle being grounded again? > The point is you are not able to quote probabilities for LLNL >because there is no meaningful test data and hence no failure >rate data, so a responsible engineer has to assume high failure >rates until proven otherwise. For some reason which I do not >understand, you seem to assume the failure rates for LLNL will be >low. Despite a random coin failing to give me heads 50% of the time, I can rely on 10 tosses to give me at least 1 head with a 99.9% reliability. If 1 head is all I need, my success rate is 99.9%. LLNL eliminates failures by eliminating launches. If Shuttle has a 2% failure rate, 28 launches are required, and 1 failure scuttles the project, there is a 57% chance of success. If the LLNL HLV has a 10% chance of failure and 1 launch is required, it has 90% chance of success ON THE FIRST LAUNCH. If a second launch is reserved in case the first fails, the chance of success rises to 99%. These are much better odds. NASA seems to have no fallback position in case of a failure. This means that the total probability of success is the product of all the sub-project successes; one failure means the entire project fails. -- Russ Cage Ford Powertrain Engineering Development Department Work: itivax.iti.org!cfctech!fmeed1!cage (CHATTY MAIL NOT ANSWERED HERE) Home: russ@m-net.ann-arbor.mi.us (All non-business mail) Member: HASA, "S" division.