Date: Tue, 16 Mar 93 05:08:17 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #317 To: Space Digest Readers Precedence: bulk Space Digest Tue, 16 Mar 93 Volume 16 : Issue 317 Today's Topics: 20Khz Power supplies. CD's in space Charon: Planet or moon? (2 msgs) Goddard responsible? NASA and congress Response to various attacks on SSF Sisters of Mars Observer (was Re: Refueling in orbit) Solar Array vs. Power Tether SSF Drag Treaties etc. (was Clementine etc.) Writing to Clnton, Gore, Aspin, etc for DC-X, DC-Y, etc. Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: Mon, 15 Mar 1993 16:04:38 GMT From: fred j mccall 575-3539 Subject: 20Khz Power supplies. Newsgroups: sci.space In <1nparsINN1a2@access.digex.com> prb@access.digex.com (Pat) writes: >In article <1993Mar11.171008.1926@mksol.dseg.ti.com> mccall@mksol.dseg.ti.com (fred j mccall 575-3539) writes: >>In <1niun0INNi6t@access.digex.com> prb@access.digex.com (Pat) writes: >> >>>In article <9MAR199308521171@tm0006.lerc.nasa.gov> dbm0000@tm0006.lerc.nasa.gov (David B. Mckissock) writes: >>>>In article <1ng5a0INN1lp@access.digex.com>, prb@access.digex.com (Pat) writes... >|>>> >|>>>Unless you were some sort of demi-god there, don't expect to >|>>>hear every story in the program. >|>>I worked in a System Engineering organization at the time, >|>>and our job was to help pull together the *ENTIRE* story >|>>concerning the SSF power distribution frequency. We >|>>worked closely with the other work packages, the Internationals, >|>>and Level II. It was our job to hear *EVERY* part of the story >| >|>There were still numerous people in Management whose job was to >|>not hear problems, but to roll the schedule. >| >|So your contention here is that someone who was there and cognizant >|must know less than someone like you who was not? This logic is as >|interesting as that of 'anonymous poster' about how it takes more >|courage to *not* be associated with what you say. >| >I never said I was there. I said, I had friends at Reston who >were very frustrated with the management structure and attitude. >These were guys who told me in 1988, the "Damn thing is not meant >to fly". Nobody said that you said you were there. The point is that the person you are arguing so vehemently with *was*. Therefore, you are arguing *at best* from second-hand rumour against someone with first-hand knowledge. >I don't have to smoke crack to think it's stupid? why should I >have to work at NASA to know this project was out of control. Given some of the things you say here, I'm not convinced that you *do* know that smoking crack is stupid. >|>>relative to the decision. My guess is that your Reston >|>>contact was outside the loop on the 20 kHz decisions, and >|>>heard spurious rumors. >|>><< Discussion attacking 20 kHz deleted >> >| >|>Not how you avoid a very resaonable discussion on how STUPID >|>the 20 KHz idea even was in the first place? >| >NOTE AGAIN: No-one at NASA or in SSF contract staff has yet >to come up with one reasonable discussion supporting the idea >of 20Khz power. I'm not sure why you think they should waste their time making a 'reasonable discussion' for your benefit, when you obviously think the only 'reasonable' discussion is one which agrees with your preformed conclusions. >|>Can you name any competent Electrical engineers, or Computer engineers >|>or PE's who thought this was a good idea? >| >|Gee, Pat, do you think an accountant dreamed it up, or what? >Yes. The idea is obviously more oriented at enriching contractors >then at producing working systems. All I can suggest to that is that you need to get out more and find out how things really work. >|Obviously there were some engineering folks who thought it *might* be >|a good idea, or it would never have been investigated in the first >|place. This is how engineering works, Pat. You look at various >|possible solutions to the problem, analyse the risks, costs, and >|benefits, and then you pick the one that seems best overall. >| >Yeah, and look at the decision they picked. They picked Most Risk, >Most Cost, Fewest Benefits. No-one disputes this. Well, let us say that no one bothers to dispute it with you. >If the decision making process makes this kind of obvious error, >what makes you think they aren't screwing up elsewhere. What 'decision', Pat? What kind of power is the Station using? >Engineering is a highly conservative field. It doesn't do things >because it sounds nice, it does things because it works. And 20Khz >never worked even on paper. Proof by assertion. Seems to be your forte. >|>Given how bad the concept of 20 KHz was, why do you expect me to believe >|>the studies on it's safety. >| >|Because he was there and you weren't? This starts to sound more and >|more like a "my mind is made up -- don't cloud the issue with facts" >|position on your part. >| >And maybe my friend at Reston was "There" and had a manager tell him >"Don't worry about the safety study, the station will never fly". And maybe he wasn't. You have, at best, second-hand information. You insist that that is better than someone else's first-hand information simply because the first-hand information doesn't support what you want to believe. So why should people bother with 'discussing' things with you? >|>Name 5 advantages to 20 KHz. I dare you. >| >|Gee, now *there* is an adult discussion. Hey, see if you can find >|some and broaden your own mind. I *double* dare you! >| >Here are a few: >1) Enrich Boeing, McDac and GD. >2) Ensure the astronauts have plenty of work to do replacing > blown out electrical gear. >3) Ensure the jobs of a lot of NASA people, because it imposes more > restrictions on the science platforms. The only appropriate response to the preceding would seem to be something along the lines of "Frog Feces!" Obviously you are too intellectually bankrupt to honestly take an adversary position in order to really analyze an idea. >|>Name 5 disadvantages to 20 KHz. Compare and assess these. >| >|>Now justify all the money spent on the 20 KHz power project. >| >Note how no-one from NASA or the SSF contractor community dares >discuss the engineering decisions on the SSF. "Dares" to? Get a clue, Pat. Given your attitude, I sure wouldn't waste my time discussing it with you. Only reason I'm bothering now is because I have a compile running and need to wait for it to finish. >|>> >|>>>Sorry, quoting some rag of documentation doesn't impress me. >|>>The 'rag' of documentation I quoted from is the Program >|>>Definition and Requirements Document, referred to as the >|>>PDRD or SSP 30000. For anyone working on SSF, this document >|>>*IS* the Holy Bible. >|>> >| >|>BIG DEAL. >|>The system requirements document. I've seen requirements documents >|>on lots of projects. ANd if the document is poorly done, it doesn't >|>matter. If the people doing the work don't care about quality >|>it doesn't matter. >| >|>It's just more paper and vapor. You guys have spent a lot of money, >|>and don't have much product to show. >| >|Once again, you seem to think you know better than someone who was >|there and has seen the things. That's not to say that there aren't >|problems; I would say there most certainly are, from what I've seen. >|However, I think you'd be better served to address the problems >|instead of random flames. >| >Hey, I have friends there. And look at skylab. THey didn't have a >"HOLY BIBLE". They had a chief engineer who was Great, and they >had a hard budget and they made the bird fly, in slightly uunder a year. Yeah, and it wasn't what they originally started out to build, either, and it basically got put up as a non-replenishable can in space. >Given the delays on SSF, it is likely SKYLAB will have more flight hours >then SSF this century. >|>>You obviously don't understand how NASA operates. For the SSF >|>>program, NASA has three Contractors responsible for building >|>>SSF hardware (McDonnell Douglas, Rocketdyne, and Boeing). A >| >|>And who is responsible for integrating their work? How come >|>that's a major management issue? >| >|Bingo! Real problem #1. >| >And why is it that 10 years into the program, they are finally addressing >a vital up-front problem? >|>>At each design review, the Contractor must provide evidence >|>>that their design meets each and every requirement. In >| >|>And how rigorous does that evidence have to be? do any >|>PE's stamp off the designs? >| >|I would say that, in general, no. Who made a PE ghod? There are lots >In general, Judge Wapner. What most CS people don't understand is that >a PE takes LEGAL responsibility for all work done under his stamp. So nice of you to tell me what "most CS people don't understand". Geez, go out and buy a clue, Pat. I seem to understand more about it than you do. Read on. >PE's like most other licensed professionals is Criminally responsible >for any failures that cause loss of life, as well as bearing a personal >liability for any civil losses. >PE's have done time for people dying, and many of them are sleepless >over things they signed off. Nobody at NASA or the Contractors is >responsible if something fails on SSF. Yeah? Name three PE's that this has happened to who didn't DELIBERATELY cut a corner or three? Hell, I'll make it easy; just name 3 PE's that this has happened to in the last, oh, 5 years. >|of good engineers who simply can't be bothered with it, since it is >|only in things like structural engineering that it becomes >|particularly meaningful. I've always found it funny that, except for >|stuff that delivers to the government (which follows more reasonable >|rules about who is an 'engineer'), I would have to get a PE to sign >|off on a software system when there is no such thing as a PE for >|software engineering. What that means is that someone who is >|specialized in a different field has to sign off on the software. >|Does this strike you as ridiculous? >| >no. it means someone is willing to lose his license over the quality >of your work. If software is going to be "Engineering" then it >better have standards and ethics, and responsibility. You mean like the ones that that PE would have to violate in order to sign off on work that I did which he cannot ascertain the quality of for himself? Check it out, Pat. A PE isn't supposed to do that. Now, consider the amount of software in *any* modern system and consider the fact that there is no such thing as a PE for software. How good do you feel now about having to have a PE sign off? "Standards and ethics, and responsibility"? You ever fly, Pat? Your life is hanging by a couple of bits of code. Ever go to the hospital? Ever drive your car? I'd suggest you find out a bit more about what you talk about *before* you talk. It might make you just slightly more credible, and you may even be able to get some real discussion of the 20 kHz power issue from someone who knows something about it. >|>>any areas where the design doesn't meet the requirement, a >|>>deviation or a waiver must be processed. >|>> >|>Or a smoke cloud is generated. >| >|>>This whole area of requirements verification is treated >|>>very seriously. >| >|>As serious as the budget over-runs? i don't think so. >| >|Then you've never been through a requirements audit. >| >Sure, I've been through them, and i've also worked on projects where >the people just kept puffing smoke as opposed to fixing problems >because they wanted to suck off the governments tit. >I've taken heat from management for refusing to sign off on >smoke requirements checklists. Well, goody goody for you. That's how the system works. >|>Basic engineering criteria and design decisions were made for SSF >|>on fatally flawed reasoning. all the paper in the world won't >|>make up for those mistakes. >| >|>I dare you to justify 3 things: >| >|Man, I can't tell you how impressed I am with such adult discussion as >|"I dare you". >| >I still don't see mcKissock willing to defend his ideas. Given your approach, I wouldn't bother either, if I were he. >|> 1) 20 KHz power developement. >| >|If you never consider anything new, you continue to build yesterday's >|systems. >| >Gee. How come my desk lamp is still 60Hz. That's yesterdays system. >But, It Works! How come my car is a diesel? It works! Why are >houses still built of wood and stone? they work! Engineering is based >upon using known solutions. >New ideas are extensively tested infield trials before use in production. Sure it is, Pat. Gee, that's why you're still using an abacus or counting stones instead of a computer, right? Engineering is *not* "based upon using known solutions". That is called 'heuristic reasoning', and it is how all those cathedrals and such got built. It's also why they fell down several times during construction and took so long to build. How come your desk lamp isn't 60Hz if you're in Europe, Pat? How come my car isn't a diesel? Funny how you manage to forget about things like economics, cost, and past investment in all of that talk about how 'engineering' works and why all those things are the way they are. >|> 2) Non Metric (english) component selection with the >|> european modules being Metric. >| >|Why should it be metric? The bulk of the funding is from the United >|States of America -- and we're not on the metric system. Why not just >|require everyone else to build non-metric to match the main station? >| >Gee, what a great defense. It's my bag of marbles, i make the rules, >even when my rules are costly and silly, "Costly and silly"? It is no more costly *to us* to use English measures for the Station. Why should we have to accomodate the smaller partners? First rule of economics and engineering is the Golden Rule, Pat; he who has the gold makes the rules. >And given it's an >international station, we have limited influence on the design of the >japanese and european modules. They do much of their own work. >In fact, one of my reston contacts was involved in trying to get the >freedom team to switch to metric sizing on fasteners and connectors. >management wouldn't allocate a few million dollars to pay for >costs for this. Why should we pay a few million dollars to pay for interconnection with stuff we didn't build? If they want to attach their modules (and they do), then they ought to by God follow the interface requirements. If that includes English measures, then that's what they're going to have to use. >|> 3) Total failure to practice EVA until this year. >| >|Fear of 'adult' critics like you who would flip out over the costs and >|risks of 'unnecessary' EVA's. >| >Gee. I'mm so glad they listen to me. >Goldin gave a speech this week, he was tired of NASA's existing mentality >and of hearing stories of the apollo age. He said we have to write >history not read it. It also looks like he is inviting the russians >to participate in SSF. Gee, that sure makes ME feel better. NOT. That's all we need is another partner who may pull out becuase of fiscal problems. We have enough of that problem domestically already. Hell, if the Russians are smart, they'll offer to build and launch the core station for the Japanese and European modules to attach to and cut us out completely. They'd probably be willing to do it on commission. -- "Insisting on perfect safety is for people who don't have the balls to live in the real world." -- Mary Shafer, NASA Ames Dryden ------------------------------------------------------------------------------ Fred.McCall@dseg.ti.com - I don't speak for others and they don't speak for me. ------------------------------ Date: Mon, 15 Mar 1993 17:21:18 GMT From: INNES MATTHEW Subject: CD's in space Newsgroups: sci.space In article <1o2675$mgk@msuinfo.cl.msu.edu> rothoff@egr.msu.edu (Eric Rothoff) writes: >I was wondering, about a week ago there was a discussion about the effects of >radiation on computer's RAM and magnetic hard drives. Would CD-ROM or CD-WORM > be effected in the same way? There shouldn't be any problem with CD's. The data on a CD is encoded optically rather than magnetically. ie data is stored on a CD in a series of physical pits in the surface rather than by playing with magnetic fields and things. -- Matt Innes ------------------------------ Date: 15 Mar 1993 11:44:27 -0500 From: Pat Subject: Charon: Planet or moon? Newsgroups: sci.space I don't know about definitions but at some size things start getting called meteors, micro-meteors/oids and space debris. The shuttle got hit by a paint fleck one time, i think at first they called it a micro-meteor, but then changed their minds after analysis. I would posit that anything smaller then we launch should be considered junk wether natural or man-made. pat not that meteors are junk, htey often have interesting science potential. ------------------------------ Date: 15 Mar 93 11:48:02 -0600 From: Bill Higgins-- Beam Jockey Subject: Charon: Planet or moon? Newsgroups: sci.space In article <1nvsprINNdml@rave.larc.nasa.gov>, C.O.EGALON@LARC.NASA.GOV (CLAUDIO OLIVEIRA EGALON) writes: > It is important to add that the mass ratio of Charon and Pluto are relatively large if > compared with other sattellites/planets in the Solar System and, if I am not wrong, > I guess that the center of mass of Charon and Pluto is somewhere in between the > surfaces of both Charon and Pluto and not below the surface of Pluto as it happens > to the Earth-Moon system. Claudio, could you keep your line length less than 72 characters, please? Not everybody has a big wide screen... Grabbing a handy table, I see that Pluto's radius is 1151 +/- 6 km, Charon's radius is 593 +/- 13 km, and the distance between them is 19,640 +/- 320 km. The mean density of the system is 2.029 +/- .032 grams/cm^3; nobody knows whether Pluto and Charon have different mean densities. Let's assume they are identical. Then we can find the barycenter by Distance of barycenter from Charon's center = [R(Pluto)^3] -------------------------- * (P-C distance) = 17,277 km (88% of the [R(Pluto)^3 + R(Charon)^3] way) A little backwards, but the barycenter is then 2363 km from Pluto's center, or more then 2 Pluto radii. So, as Claudio's intuition suggests, the barycenter is way outside the surface. Of course, what Shakespeare | Bill Higgins, Beam Jockey ORIGINALLY wrote was "First thing | Fermi National Accelerator Laboratory we do, let's kill all the EDITORS."| Bitnet: HIGGINS@FNAL.BITNET But for some reason it didn't | Internet: HIGGINS@FNAL.FNAL.GOV survive past the first draft. | SPAN/Hepnet: 43011::HIGGINS -- David D. "Laserdave" Levine (davidl@ssd.intel.com) ------------------------------ Date: Mon, 15 Mar 93 15:24:59 EST From: Tom <18084TM@msu.edu> Subject: Goddard responsible? >>Before you go getting upset about the uses his invention were put to, >>don't forget the great train of chemical discoveries necessary for >>the development of nerve gas or penecillin (sp?), or the invention of the >>automobile, responsible for untold numbers of marriges and conceptions, >>as well as 350,000 deaths annually in the U.S., or... Forrest sez; >I believe you have added about 300,000 to fatalities due to >auto accidents annually in the US. Or did you mean casualties? Could be. The point is, users, not inventors, are responsible for the use of a technology, good or bad. -Tommy Mac ------------------------------------------------------------------------- Tom McWilliams | 517-355-2178 (work) \\ Inhale to the Chief! 18084tm@ibm.cl.msu.edu | 336-9591 (hm)\\ Zonker Harris in 1996! ------------------------------------------------------------------------- ------------------------------ Date: Mon, 15 Mar 93 15:43:34 EST From: Tom <18084TM@msu.edu> Subject: NASA and congress Brian sez; >Major sigh...I think most of us within NASA who read these >threads look at them with a sense of resignation. People >like Nick Szabo and Tom McWilliams are so misinformed, >it's depressing to even attempt to correct them. I'm curious to know what it is you think I've been mislead on. If you belive I'm misinformed about real problems existing at NASA, then you've been highly insulated. Some of us that make up 'the public' do care, and have learned of such problems. My assertation is that the worst problems are inherent in NASA's nature, and that correcting those problem means destroying NASA. Maybe replacing it, maybe balkanizing it. >But let me be absolutely clear from the beginning. >I think it *is* NASA's fault that they are misinformed. >NASA's PR in general has been pathetic (until very >recently). JPL, for example, has great PR, and that's >why people like Tom realize they do great work (and they >*do* in fact do great work). However, the other elements >of NASA are also just as productive and capable. And the >counter-example is true - there are several major flubs >on JPL's record too. Flubs I can deal with. We're all human here; mistakes get made. But some mistakes are systemic. And here you are, saying PR isn't good enough. The problem is not the public learning of NASA's flaws. The problem is NASA's flaws being ignored. Better PR will only exacerbate the problem. >I do not pretend to claim that there haven't been any >mistakes in the design and implementation of NASA >programs, for there have been many. But that is the >nature of things when you are doing things for the >first time - and I sometimes think people forget that's >what we're doing. I would further argue that no The mistakes I have the biggest problems with are not those occurring due to the nature of NASA as a leading-edge R&D facility. Mistakes will be made, problems will occur, and we do our best. The problems I have are those that result from NASA's nature as a gov. agency. Slowness to respond to circumstances. Projects being directed by political, not design and cost concerns. This is why the classic 'congresses fault' defense is bogus. Since much of NASA's history and funding has come from congress-directed goals (Shuttle, Apollo, Fred), problems with congress are problems at NASA's heart. You can't work around them, but the people at NASA could get out from under them. >collection of private consortiums could have done *any* >better with the given resources. I know this is a With the given resources, I disagree. With their own resources, I think they could still do it, or at least some of it. But this is an untestable hypothesis, as NASA has created a record of monopoly action; doing their best to ruin competition, with gov. subsidy advantages. People won't keep putting their fortunes on the line to see them destroyed by a monopoly with political, not creative, motivations. This, I think, is the most damaging aspect of NASA. What good is the practical knowledge gained by NASA, if it doesn't get used to better our lives? Given the same resources, what special skill/quality does NASA posess that would make it more effective than a private group? Could the people at NASA have accomplished more with the same resources, but no hinderence from Congress? If the answer is yes, then what you need to realize is that those limitations are inherent in NASA. If the answer is no, why are they hinderences? >badly bruised and beaten horse, but the fact of the >matter is that the lack of vision in Congress has been >a major contributing factor to many of NASA's difficulties. Could you have a NASA without a Congress? No. So arguments like this aren't a defense of NASA, they are support for the fact that NASA, as a gov. agency, will continue to fail, in very important respects. It's not the fault of NASA's people that NASA fails. But it is their fault if they stay there, and support a flawed structure in the belief that it will get better. And they will pay the price the day NASA is finally shut down, when congress decides, oblivious to their own actions being the cause, that NASA doesn't work. Then we lose the good things that NASA does, too. What's wrong with breaking NASA into it's component pieces, and allowing them to get funding based on thier results. Then, the Shuttle ops, a monopolized, inefficient transportations system, would no longer be supported by a public that likes what JPL does. I bet we'd have a CRAF, if it had been done that way. >Most (if not all) of the frustrating shortcomings in Shuttle >and Station are due to inadequate, unrealistic and >fickle funding. The technological know-how within NASA >is there. The bureaucracy of government procurement >forced on NASA is another stumbling block. If Congress >could find the wherewithal to commit to a multi-year >project, we might have had Station years ago. The technical know-how is not a NASA-based commodity. That know-how could as easily have been applied outside of a gov. agency, where it wouldn't be subject to the congress-mandated limitations that you believe are fundamentally non-NASA. Since their actions affect NASA, and determine what NASA does, and determines funding, they are NASA, as much as the technical know-how is NASA. BTW, we did have a station years ago :-) It died because of actions of NASA & Congress. There are goals in space that would be better met by private free enterprise. Yet NASA has consistently blocked these efforts, trying to protect the Shuttle, for example, from competition in launching services. Do you defend this as well? -Tommy Mac ------------------------------------------------------------------------- Tom McWilliams | 517-355-2178 (work) \\ Inhale to the Chief! 18084tm@ibm.cl.msu.edu | 336-9591 (hm)\\ Zonker Harris in 1996! ------------------------------------------------------------------------- ------------------------------ Date: 15 Mar 1993 11:32 EST From: "David B. Mckissock" Subject: Response to various attacks on SSF Newsgroups: sci.space In article <1niun0INNi6t@access.digex.com>, prb@access.digex.com (Pat) writes... > >>You obviously don't understand how NASA operates. For the SSF >>program, NASA has three Contractors responsible for building >>SSF hardware (McDonnell Douglas, Rocketdyne, and Boeing). A > >And who is responsible for integrating their work? How come >that's a major management issue? The Space Station Program Organization is similar to the Apollo & Shuttle organizations. Level I, based at NASA Headquarters, is responsible for the overall management and stragetic planning of the program. The Program Director is located at Level I, his name is Dick Kohrs. Level II, located in Reston, is responsible for developing the space station, and controlling the internal and external interfaces. Mr. Robert Moorehead runs Level II, his title is Deputy Program Director. He runs the program on a day-to-day basis, and he's the one responsible for integrating the work done by the various Level III centers (JSC, MSFC, LeRC, and KSC). > >>key part of our Contracts with these folks are their >>requirements documents. Each NASA center tailors the >>requirements in the PDRD for their individual contract, and > >And how many requirements got dropped on the floor between the >three tailoring jobs? Who has the contractual obligation >to the whole thing? Level II spends alot of time ensuring that each and every requirement in their Program Definition & Requirements Document (SSP 30000) get's flowed down correctly to the prime contractors and their subcontractors. Level II has developed some software called ARMS (Automated Requirements Management System) to help out with Requirements Traceabilty. With ARMS, you can pick any requirement out of SSP 30000, and get the trace down to the Level III requirements documents, and the Contract End Item specifications, and the individual specifications for each box. I can site one specific example of how important Level II treats this subject. I participated in WP-4 CDR two weeks ago. Personnel from Level II had writtein RIDs (Review Item Discrepancies) indicating that some recently baselined Level II documents were not yet part of the Contract for some of the WP-4 subcontractors. WP-4 management took an action item to flowdown all current directives on contract into the necessary product specifications (and thereby get them on the subcontractors contracts). >IF the requirements document is such a holy bible, how come >Moorehead had to re-establish two-fault tolerance into vital >stabilization and propulsion systems? > >That was a part of the work package 2 cost over-run. >I am not impressed with people waving and screaming about the >quality of the paper trail. I llok at the work. > Your premise is: SSP 30000 required two-fault tolerance in the stabilization & propulsion systems, WP-2 wasn't meeting that requirement, Moorehead "re-established" the requirement, and then WP-2 had a cost over-run. Wrong premise. The program failure tolerance requirements were reduced to save money (either during the Turbo team activities in 1990 or as part of Restructuring in 1991, I can't remember exactly). Mr. Moorehead put-back in the two-fault tolerance requirement as part of an Engineering Design Council suggested changes. The requirement was never being ignored, it was simply deleted and then re-instated. >I dare you to justify 3 things: > > 1) 20 KHz power developement. First, two disclaimers. One, I'm a systems engineer, & therefore focus on the 'big picture', and I'm not an expert in 20 kHz. Second, although I'm from Lewis Research Center, I'm currently working at NASA Headquarters, so I don't have access to all of my files from the Phase B activities where we studied the system impacts of using 20 kHz, nor access to the LeRC library, with proceedings from conferences like IECEC (where papers on the benefits of 20 kHz have been presented). As I recall from the Phase B studies, using a 20 kHz distribution frequency for the SSF resulted in lower weight, better efficiency, and better safety characteristics than 400 Hz and/or DC systems. As I stated in an earlier e-mail, LeRC has run a testbed with 20 kHz components for a long time. And, to preclude another rebuttal from Dennis, I'll acknowledge that MSFC apparently had problems running 20 kHz components in their lab, although I am unaware of their specific problems. > > 2) Non Metric (english) component selection with the > european modules being Metric. I don't see that this is that big of a deal. I had to learn both sets of units in school. I remember a Change Request being processed several years ago to modify the units to use metric on all SSF drawings, schematics, analyses, etc. The CR was reviewed and costed by the work packages, and Level II ended up rejecting the CR, due to the high estimated costs to implement the change. > > 3) Total failure to practice EVA until this year. Another common fiction on sci.space. NASA has two facilities for practising EVA's in water tanks, one at JSC, and another at MSFC. WP-4 has tested many of our EVA procedures in these facilities. For example, in December 1992, we tested 22 assembly/operations procedures in the MSFC Neutral Buoyancy Facility (NBF). Astronauts were involved in the tests. Some of the key tests included changeout of the battery, radiator, and mast cannister Orbital Replacement Units (ORUs). These were key tests, because these ORUs are large, and we hadn't practised changing out these big ORUs before. The tests included many of the procedures needed to assembly the EPS on-orbit, such as solar array blanket box launch restraint release. ------------------------------ Date: 15 Mar 1993 11:47:57 -0500 From: Pat Subject: Sisters of Mars Observer (was Re: Refueling in orbit) Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: |In article <1o02maINNppt@access.digex.com> prb@access.digex.com (Pat) writes: |>|The MO spares are already being rummaged through for use on other missions. |> |>I thought MO was supposed to be one in a whole series of spacecraft? | |The key word is "was". The Observer series is dead, a victim of |overenthusiasm and overoptimisation on the very first mission, which |overran the original budget and schedule ideas so badly that nobody is |going to try again. |-- How many were planned in the Mars Observer series? ANd why did they use the TOS stage for the titan? launch. why not use the centaur. a much more proven launch vehicle. pat Plus, how much was the series planned to cost and take time for, and how much did they actually spend and take time to do. How did this compare to the viking lander series cost? ------------------------------ Date: Mon, 15 Mar 1993 16:38:39 GMT From: fred j mccall 575-3539 Subject: Solar Array vs. Power Tether SSF Drag Newsgroups: sci.space In kcarroll@zoo.toronto.edu (Kieran A. Carroll) writes: >(I love a challenge :-) >We've recently been told here that the reboost modules weigh >12,000 pounds. Assume that 10,000 pounds of that is hydrazine, >which we will assume will be burned with a specific impulse >of 350 lbf-sec/lbm. This means that one module's >worth of hydrazine would provide an impulse of 3.5E6 lbf-sec >to SSF, or about 1.56E7 N-sec. in metric units. I believe there is only around 6000 pounds of fuel in a thruster module (based on what I've seen posted here). >Oh well, tethers create 5 times as much drag as this, for the >same amount of power generated. If you want to generate electricity >by burning hydrazine, it looks like you'd be better off doing >it in an APU, which wouldn't affect your orbital altitude... The conclusion still seems to work, though. Just by a smaller factor. -- "Insisting on perfect safety is for people who don't have the balls to live in the real world." -- Mary Shafer, NASA Ames Dryden ------------------------------------------------------------------------------ Fred.McCall@dseg.ti.com - I don't speak for others and they don't speak for me. ------------------------------ Date: 15 Mar 93 07:01:46 GMT From: Pat Subject: Treaties etc. (was Clementine etc.) Newsgroups: sci.space,sci.econ In article flb@flb.optiplan.fi ("F.Baube x554") writes: |Phil G. Fraering |> Saying the Russians and other citizens of the CIS should be responsible |> for the debts of previous dictatorial governments would still be slavery |> and morally repugnant as such even if they could pay for it... and they can't. | |Yup, international law's a bitch. This even happens to our *friends*, |like the Phillipines for instance. We let'em run up a tab while ol' |Ferdinand pocketed a goodly chunk of it all, and then they're obligated |to repay it. We're hardly blameless, the US of A. | The basic principle is the same, debts are owed by the country, not by the government, the officials of the government, but by the people and territories of the former nation. Now new governments may oftentimes convince foreign debtors to write off old debts, but we want to not allow precedent for a mere revolution to terminate debts, otherwise international lending might become impossible. Bolivia has had what? 150 revolutions in 120 years of existence? No-one could conduct trade with bolivia on that basis. no treaty or contract would be good for more then 6 months. Italy, changed governments 30 times in 50 years. How would the bank of rome, ever be able to write international credit letters? France changed governments once, twice since WW2? yet they participate in the international money order? One of the most controversial things the new federal government of the USA did was assume the Debts of both the continental congress and the American Confederacy of states. Hamilton did that, to make the US a respectable trade partner to europe, and also give the Feds a reason to levy taxes. A more controversial action was when Johnson, repudiated the COnfederate state debts. A lot of people were looking to washington to cover that and they were told, back some bunch of rebels and get stuck. But really this is way off from sci.space. folluw up to sci.economics. pat ------------------------------ Date: Mon, 15 Mar 1993 18:56:22 GMT From: Nick Haines Subject: Writing to Clnton, Gore, Aspin, etc for DC-X, DC-Y, etc. Newsgroups: sci.space After my last post here (reporting my receipt of a reply to my letter to Les Aspin supporting SSTO), I was asked by email for addressses to write to. Here they are: President Bill Clinton, 1600 Pennsylvania Ave NW, Washington DC 20500 Vice President Al Gore, Office of the Vice President, Old Executive Office Building, Washington DC 20501 Vice President Al Gore, S-212, Washington DC 20510 [this address is apparently better] Senator Les Aspin, Secretary of Defense, The Pentagon 3E880, Washington DC 20301 Director Leon Panetta, Office of Management and Budget, Room 252 Old Executive Office Building, 17th St & Pennsylvania Ave NW, Washington DC 20503 As for what to say, the key things are these: - keep the letter short, and state your reason for writing in the first sentence. Otherwise it probably won't get read. - describe the project as `the SDIO Single Stage Rocket Technology program'. - ask for continuing funding `to develop an orbital prototype' (this is DC-Y). - emphasize the importance of cheap launch technology to American industry when writing to Clinton and Gore, and to American defense when writing to Aspin. - If you can, disclaim yourself from SSRT; I said "I have no direct involvement with SSRT; this is not an appeal for pork" etc. Nick Haines nickh@cmu.edu ------------------------------ End of Space Digest Volume 16 : Issue 317 ------------------------------