Date: Thu, 25 Feb 93 05:02:09 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #224 To: Space Digest Readers Precedence: bulk Space Digest Thu, 25 Feb 93 Volume 16 : Issue 224 Today's Topics: Beamed power transmission on Mars? Getting people into Space Program! McElwaine disciplined! (somewhat long) military aircraft Neil Armstrong (2 msgs) Nobody cares about Fred? (2 msgs) Plans for Phobos/Diemos? Reliable Source says Freedom Dead, Freedom II to be developed (3 msgs) Sabatier Reactors. Shuttle refueling was(Re: Sabatier Reactors.) space funeral (was Human Distance Record:Apollo 13 ) unnecceary violence (was: Nobody cares about Fred?) UN Space Agency? what is the force of gravity X-15 astronauts (was Re: Getting people into Space Program!) 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: 23 Feb 93 18:13:32 GMT From: Jeff Bytof Subject: Beamed power transmission on Mars? Newsgroups: sci.space I was wondering if it would be worth considering a power source for future human exploration of Mars that used a solar radiation collector in Mars orbit and beamed microwaves or lasers to receivers on the surface. Perhaps the laser option would work best as the size of the receiving antenna would be smaller and perhaps highly portable. That way, much longer traverses away from the central base might be possible, decreasing the amount of fuel the rovers would have to carry along. -rabjab ------------------------------ Date: Tue, 23 Feb 1993 16:46:03 GMT From: fred j mccall 575-3539 Subject: Getting people into Space Program! Newsgroups: sci.space In <1993Feb22.214145.29263@ke4zv.uucp> gary@ke4zv.uucp (Gary Coffman) writes: >In article <1m8q61INNmh9@access.digex.com> prb@access.digex.com (Pat) writes: >>Most Military aircraft dont have weapons until one is designed >>for it. Hardpoints are only part of the issue. control systems >>need to be built and weapons dynamics have to be tested. >>Somehow I figured, that if someone wanted badly enough to >>put a sensor or weapon onto the X-15, the engineering would >>not be implausible. Somehow, I doubt designing a hard point >>would have been beyond the design team. The engineering would be *quite* implausible. There was no room internally, and you don't just randomly hang on external loads when a vehicle moves at those kinds of speeds. >Most modern military combat aircraft are best appreciated as an >envelope designed around a particular set of weapons systems. >The skinless F-86 at the Air Force Museum highlights this very >well. The X-15 was designed without provision for internal stores, >and without provision for external structural hardpoints. Adding >either of these is not simply a matter of tacking them on. Mass >distribution and balance of the vehicle would be highly impacted >by carrying stores. Also, hypersonic weapons release from a hardpoint >has never been demonstrated. Some designers seem to think it's a very >difficult problem. The closest thing, a SR-71 launched drone, turned >out to be a hard enough problem that the drones were refitted to >B-52 under wing launching. Actually, I believe there were prototypes of a slightly smaller SR-71 variant (YF-12A) designed as a Mach 3 interceptor which had 4 internal weapons bays for air to air missiles and an intercept radar in the nose (I remember building a model of it when I was young). However, I believe that the way this worked was to 'forcefully eject' (read 'explode') the missiles away from the aircraft as they fired. Also, note that these are powered loads. I'd question trying to get drop-loads to work at those speeds. I don't konw if the prototypes ever fired any weapons, and I recall talk that if they'd decided to actually go ahead with the interceptor version they would have wound up using the larger SR-71 airframe. -- "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: 23 FEB 93 10:49:23 From: Tom Randolph Subject: McElwaine disciplined! (somewhat long) Newsgroups: sci.skeptic,sci.space,sci.astro In article <1993Feb20.195334.26182@selway.umt.edu>, cs000rjp@selway.umt.edu (Russell J. Pagenkopf) writes... >In article <24861@alice.att.com> ark@alice.UUCP () writes: >>It always worries me when someone is stomped on because of what he says, >>even if what he says is unadulturated gibberish. Are we so thin-skinned >>that we can't just ignore stuff we don't want to see? > >* SOAPBOX ON * > >I must agree with you Andrew. Just because *you* (newsgroups in >general) don't agree with what someone has to say doesn't mean you have the >right to CENSOR him/her. Yes, but do you realize that "MacElwaine" is most likely some sort of batch job that's going through the list of newsgroups, randomly posting OVER CAPITALIZED rubbish to them? If the person had the stones to actually post something live on line, maybe I'd agree. This is the net-equivalent of junk mail or those computerized telephone sales gimmicks that call you when you're sitting down to dinner. The ultimate bandwidth-waster. By the way, try sending him mail, asking a question about the postings. You will not get any answers, only another random posting of rubbish mailed directly to you. I've tried several times. Apparently there's a mail-answering server program running. -Tom R. randolph@est.enet.dec.com ------------------------------ Date: Tue, 23 Feb 1993 17:30:30 GMT From: fred j mccall 575-3539 Subject: military aircraft Newsgroups: sci.space In <730361606.AA04238@csource.oz.au> Matthew.Tarascio@f532.n635.z3.fidonet.org (Matthew Tarascio) writes: >Dear Sir, > My ambition is to become aeronautical engineer who will hopefully one >day work in the U.S. for Lockheed. At the moment I am only 17 so I have a >little way to go yet, but hopefully I will get there. Anyway I was wondering >about a project that your company was undertaking about the new ATF or F22. I >was wondering when the F22 was going to take the place of the F15 and whether >its opponent, the F23, was going to take the place of the F14. I would not count on the F-23 replacing the F-14 anytime soon. I would expect that the changes necessary for carrier operations would make the aircraft excessively heavy. Also, re-engined F-14's have been demonstrated to achieve supersonic cruise on military power (it's a good airframe design), and the Navy still likes the idea of being able to 'reach out and touch someone' with Phoenix. Given reasonable money for upgrades (which is proving difficult for them to get), the F-14 design is probably good well into the future. >Also I was >wondering whether there was a replacement for the Grumman A-6 Intruder looming >in the future, I have heard rumors that a plane named the Aurora was to take >its place being a mach 4+ aircraft. The A-12 was intended to replace the aging A-6. It ran into management problems, overran budget, and has been cancelled. Aurora is the (rumoured only) replacement for the SR-71 Recce aircraft, which has (once again, rumoured only) reportedly been flying for a number of years now. -- "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: 23 Feb 93 16:42:05 GMT From: CLAUDIO OLIVEIRA EGALON Subject: Neil Armstrong Newsgroups: sci.space,sci.astro > Does anyone know the current whereabouts of Neil Armstrong? > What does he do these days? According to a letter that Neil Armstrong wrote to the people that was organizing the X-15 First Flight 30th Aniversary Celebration in June 1989 at Ames, at that time he was working at NASA Headquarters. I do not know if he is still there but since that letter was written almost four years ago, it is likely that he is still there. ------------------------------ Date: 23 Feb 93 18:19:19 GMT From: George Wm Turner Subject: Neil Armstrong Newsgroups: sci.space,sci.astro > Does anyone know the current whereabouts of Neil Armstrong? > What does he do these days? last i heard he was an engineering professor at the University of Cincinnati, Ohio. ------------------------------ Date: Tue, 23 Feb 1993 16:23:20 GMT From: fred j mccall 575-3539 Subject: Nobody cares about Fred? Newsgroups: sci.space In <1mbf66INNcrm@mojo.eng.umd.edu> sysmgr@king.eng.umd.edu (Doug Mohney) writes: >In article , umandru1@umanitoba.ca (John Andrusiak) writes: >>In fact, materials engineering seems to be a better understood science >>that software engineering, if only because materials engineering has been >>around longer. >Software engineering yahhh... Kinda like "military intelligence" hmmm? Yeah, sure. Of course, you probably also want to say that the Tacoma Narrows bridge was a *software* failure, too. So tell me again how there's no such thing as software engineering because it isn't predictable and well understood like 'real' engineering -- like, say, bridge design and construction . . . -- "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: Tue, 23 Feb 1993 17:32:40 GMT From: Mary Shafer Subject: Nobody cares about Fred? Newsgroups: sci.space On Tue, 23 Feb 1993 16:23:20 GMT, mccall@mksol.dseg.ti.com (fred j mccall 575-3539) said: FMC> Of course, you probably also want to say that the FMC> Tacoma Narrows bridge was a *software* failure, too. So tell me FMC> again how there's no such thing as software engineering because FMC> it isn't predictable and well understood like 'real' engineering FMC> -- like, say, bridge design and construction . . . Actually, the Tacoma Narrows bridge isn't a very good example of a failure in understanding and predicting physical phenomena. Structural resonance was not well understood at the time and the unique site was not recognized as being likely to induce the problem. However, the bridge built 20 years later in Tennessee (?) in the same sort of terrain that failed in exactly same manner was. Every dog (profession) is allowed one bite. Comets and their window corners, Electras and their whirl modes, swept-wing aircraft and inertial coupling.... If you constrain designers to never make errors you also constrain them to never do anything new. On the other hand, if we built buildings the way we write software, the first woodpecker to come along would have destroyed civilization. -- Mary Shafer DoD #0362 KotFR NASA Dryden Flight Research Facility, Edwards, CA shafer@rigel.dfrf.nasa.gov Of course I don't speak for NASA "A MiG at your six is better than no MiG at all." Unknown US fighter pilot ------------------------------ Date: 23 Feb 93 18:05:16 GMT From: Jeff Bytof Subject: Plans for Phobos/Diemos? Newsgroups: sci.space Are there any current plans to land in Phobos and/or Diemos? -rabjab ------------------------------ Date: 23 Feb 93 17:44:11 GMT From: "Allen W. Sherzer" Subject: Reliable Source says Freedom Dead, Freedom II to be developed Newsgroups: sci.space In article <23FEB199310324877@judy.uh.edu> wingo%cspara.decnet@Fedex.Msfc.Nasa.Gov writes: >The problem with this design is that the problems with EVA and on orbit >maintenance is magnifed tenfold. Not only do you have to do all of the >EVA associated with the external structure, BUT you have to do EVA to >install all of the internal equipment, life support..... AND then do >all of your testing on orbit. But Dennis, this is pretty much what NASA planned to do with Freedom before the micromanagers in Congress insisted on greater integration to minimize this problem. NASA disagreed saying on orbit instalation wasn't a problem. So you agree with Congress and disagree with NASA. I'm glad we find ourselves in agreement. >Then when things don't work which will happen >you have to have all of these contingency missions just to correct all of >the things you did not know about till you got there. Which is why the growth in logistics shuttle flights was called 'alarming' in an internal NASA briefing in early 89. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------112 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: Tue, 23 Feb 1993 17:38:36 GMT From: fred j mccall 575-3539 Subject: Reliable Source says Freedom Dead, Freedom II to be developed Newsgroups: sci.space In <1mb6scINNt87@access.digex.com> prb@access.digex.com (Pat) writes: >My feeling was something with a truss, in a higher more inclined orbit. >then modify the ETs so they have hatches and "wet" structure. >Then just hang those onto the Truss, and bring equipment up in the shuttle >bay. this was an original SKYLAB concept. >THe way I see it, is you get a quick volume, cheap and NASA only has >to worry about the trusses and tanks and maintenance. any experiments >can bring up their gear and the mission specialists can >install it. If a submarine can be serviced entirely through >little hatches, i am sure a station could be too. Except that submarines (and ships in general) typically aren't. Visit a shipyard sometime, if they'll let you in. -- "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: Tue, 23 Feb 1993 16:35:14 GMT From: Gary Coffman Subject: Reliable Source says Freedom Dead, Freedom II to be developed Newsgroups: sci.space In article <1mb6scINNt87@access.digex.com> prb@access.digex.com (Pat) writes: > >My feeling was something with a truss, in a higher more inclined orbit. >then modify the ETs so they have hatches and "wet" structure. >Then just hang those onto the Truss, and bring equipment up in the shuttle >bay. this was an original SKYLAB concept. > >THe way I see it, is you get a quick volume, cheap and NASA only has >to worry about the trusses and tanks and maintenance. any experiments >can bring up their gear and the mission specialists can >install it. If a submarine can be serviced entirely through >little hatches, i am sure a station could be too. Actually it's shockingly common to torch a big hole in a sub, replace equipment, and re-weld it. A co-worker served on a sub tender and was involved in several such servicing operations. It's also a common practice on surface ships. Lots of shipboard equipment is too big for the little hatches. Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | | ------------------------------ Date: Tue, 23 Feb 1993 17:35:47 GMT From: fred j mccall 575-3539 Subject: Sabatier Reactors. Newsgroups: sci.space In <1mb6d9INNscb@access.digex.com> prb@access.digex.com (Pat) writes: >In article <1993Feb19.180801.18926@mksol.dseg.ti.com> mccall@mksol.dseg.ti.com (fred j mccall 575-3539) writes: >|>> >| >| >|>If people are going to defend the shuttle as this marvelous >|>workshop, then i suggest we see it do some real workshop >|>type activities. Refueling satellites is a very reasonable >|>mission, and it seems beyond the shuttles capacity. >| >|>I would view this example as a reasoonable argument that the >|>shuttle is a lousy workshop. >| >|Perhaps you should consider viewing it as a reasonable argument that >|there aren't any satellites to speak of that are equipped for 'in >|space' refueling, instead? It has nothing to do with the Shuttle's >|suitability or non-suitability as a workshop. >| >Fred. > Perhaps you should read all of the thread before posting. Perhaps I did. Perhaps you should look at the contention that was being responded to before critcizing? >No, no satellittes are equipped for in-orbit refueling, because >NASA won't do it. Why add a point of failure toa system if >you can't get gas. The centaurs could have been equipped for >this sort of work, but no-one at NASA has the guts to do this. >If you have a workshop but the mechanic is afraid to open the >hood, you have a problem. I am sure the galileo project office >would have been quite happy to have a direct trajectory to jupiter. What does this have to do with what I was responding to, which was the contention that the Shuttle is a bad workship because it doesn't have the capability to refuel satellites? The problem is not (as you explain) with the Shuttle at all, so what does this have to do with anything? >I am sure a lot of other missions would have been happy to use the centaur. >But NASA won't fly a fueled centaur, and won't fuel an empty >centaur in orbit. So we end up with a problem. But what does this have to do with the utility of the Shuttle as a workshop? Absolutely nothing, so far as I can tell. >If we had a centaur on galileo, we probably could have then had >the shuttle crew, EVA to fix the stuck antenna. instead, antenna >deploy had to be put off until after the venus encounter. And if pigs had wings, they would probably fly and the rest of us would carry large umbrellas everywhere we went. Once again, what does this have to do with the contention that the Shuttle is a poor workshop because it can't refuel satellites that aren't built for refueling and where the problem is managerial rather than anything to do with the capability or non-capability of the Shuttle? -- "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: Tue, 23 Feb 1993 16:46:29 GMT From: Gary Coffman Subject: Shuttle refueling was(Re: Sabatier Reactors.) Newsgroups: sci.space In article <1993Feb22.181411.1@fnalf.fnal.gov> higgins@fnalf.fnal.gov (Bill Higgins-- Beam Jockey) writes: >In article <1993Feb21.181418.22481@ke4zv.uucp>, gary@ke4zv.uucp (Gary Coffman) writes: >> Throwing in an EVA just for the hell >> of it is really silly. With pre-breathe, it's very consuming of precious >> on orbit astronaut time. There has to be a pressing reason to do EVA. > >Hmm... If, as NASA has announced and Allen Sherzer has "applauded," >they want to gain EVA experience, it is not only useful to do even >simple and dumb EVA tasks, it is useful to *repeat* the same ones with >different astronauts. This serves a dual purpose: it gives you more >statistics for performance measurements on the task, and it gives >experience with it to more astronauts. Both seem to me good reasons >to do lots of EVAs in an engineering program. I expect we'll see much >more of the "spaceman's carry" and similar experiments. I rather expect to see different skill sets practiced on each flight, repeating only those that cause difficulty. Even with EVA on every flight, we won't be doing *that* many EVAs. It makes sense to explore as many capabilities as possible. >> Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary >> Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary >> 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary >> Lawrenceville, GA 30244 | | > >Overnight? No, sometimes it takes months; unless we use explosives. :-) Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | | ------------------------------ Date: 23 Feb 93 16:29:15 GMT From: CLAUDIO OLIVEIRA EGALON Subject: space funeral (was Human Distance Record:Apollo 13 ) Newsgroups: sci.space < (I heard an item on the news that a Japanese company will be selling < burial stations for ashes on the moon - the above would be the logical < extension for some wealthy trekkite ). That makes me remind that a group of American entrepreneurs tried to sell this kind of service and they were getting lots of customers for that **however** someone came in and said that the law would not allow them do that (there were all sorts of strange reasons for that). They guys tried to work this thing out but hassle was so big that they finally gave up. Later on they said that if Americans can't offer this kind of service eventually the Japoneses will do so... Well the guys were right... C.O.EGALON@LARC.NASA.GOV ------------------------------ Date: 23 Feb 1993 15:59:49 GMT From: Doug Mohney Subject: unnecceary violence (was: Nobody cares about Fred?) Newsgroups: sci.space In article <1mcergINNjk2@darkstar.UCSC.EDU>, bafta@cats.ucsc.edu (Shari L Brooks) writes: >In article <1lotstINNsdh@mojo.eng.umd.edu> sysmgr@king.eng.umd.edu writes: >>Just get an AK-47, go down to NASA HQ, and start shooting everyone wearing a >>tie who might be NASA management. It's the ONLY way you'll be happy. > >Doug, this urging Allen to get a gun and kill people is beginning to get >out of hand. Once was funny, and twice made your point. But seeing you >repeatedly hammer on this is really disturbing. Are you sure you're not >projecting? Thank you for that pop psycho-analysis. However, the initial point stands. Mr. Sherzer will not be happy until every stinkin' burrrreo-crat in NASA is unemployed and out on the street, so America (waive flag for knee-jerk reaction) can once again assume it's manifest destiny in the Universe. The truth, which you chose to cut out, is that Allen's random spray-and-condemn attacks insult a lot of people working at NASA who are busting a gut to do their jobs to the best of their abilities, and within the limitations imposed upon them by a variety of sources. His posts have become increasing bitter. Anyone who cries "Conspiracy" and can't back it up with documentation is, at best, creating fiction. I have talked to Ehud, and lived. -- > SYSMGR@CADLAB.ENG.UMD.EDU < -- ------------------------------ Date: 23 Feb 93 16:45:38 GMT From: CLAUDIO OLIVEIRA EGALON Subject: UN Space Agency? Newsgroups: sci.space I do not know if there is a UN Space Agency but I do know that they have some kind of group that deals with Space issues. I guess your best bet would be to contact UN in New York. ------------------------------ Date: 23 Feb 93 15:16:13 GMT From: Dave Jones Subject: what is the force of gravity Newsgroups: sci.space 00wtripley@leo.bsuvc.bsu.edu wrote: > > space is big .really big. You have no idea how vastly hugely mind-bogglingly big it is... (Douglas Adams, "The Hitch-Hikers Guide to the Galaxy"). Now that the quotes are out of the way, what were you saying? -- ||||||||||||||||||||||||||||||||||||||||Marketing is the business of selling || Honk if you like Einstein |||||||||||projects to management. ||------------------------------------------------------------------------ ||Dave Jones (dj@ekcolor.ssd.kodak.com)|Eastman Kodak Co. Rochester, NY | ------------------------------ Date: 23 Feb 93 04:58:41 GMT From: Bill Higgins-- Beam Jockey Subject: X-15 astronauts (was Re: Getting people into Space Program!) Newsgroups: sci.space In article <1mb5soINNrs8@access.digex.com>, prb@access.digex.com (Pat) writes: > In article <22735@ksr.com> clj@ksr.com (Chris Jones) writes: > |In article <1m8q61INNmh9@access.digex.com>, prb@access (Pat) writes: > |> > |>Seriously. My point was that the X-15 was qualifying astronauts > |>at a rate that I think the SHuttle only passed recently. > | > |I don't think so. I believe there were 99 X-15 flights TOTAL. Not all of them > |went high enough to earn the pilot astronauts wings (most did not, I believe -- I think Chris is right on this. The number of X-15 pilots qualifying as astronauts (some criterion like reaching an altitude greater than 80 km) was really small, like about three. Wish I had the references to check. > WHat I don't understand > is why yeager never flew one of these. I don't recall > seeing him on the mission list. Anyone have an answer for > this? I guess he must have had a different job at the time. What *I* want to see is Chuck Yeager wearing one of those baseball caps that say "X." -- O~~* /_) ' / / /_/ ' , , ' ,_ _ \|/ - ~ -~~~~~~~~~~~/_) / / / / / / (_) (_) / / / _\~~~~~~~~~~~zap! / \ (_) (_) / | \ | | Bill Higgins Fermi National Accelerator Laboratory \ / Bitnet: HIGGINS@FNAL.BITNET - - Internet: HIGGINS@FNAL.FNAL.GOV ~ SPAN/Hepnet: 43011::HIGGINS ------------------------------ Newsgroups: sci.space From: fred j mccall 575-3539 Subject: Re: Nobody cares about Fred? Message-Id: <1993Feb23.161638.23566@mksol.dseg.ti.com> Organization: Texas Instruments Inc References: <1993Feb18.093703.28426@ke4zv.uucp> <1993Feb18.155736.1657@iti.org> <76000@cup.portal.com> <1993Feb22.004727.1387@iti.org> <76273@cup.portal.com> Date: Tue, 23 Feb 1993 16:16:38 GMT Lines: 60 Sender: news@CRABAPPLE.SRV.CS.CMU.EDU Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU In <76273@cup.portal.com> BrianT@cup.portal.com (Brian Stuart Thorn) writes: >>In article <76000@cup.portal.com> BrianT@cup.portal.com (Brian Stuart Thorn) w >r >>ites: >> >>> I'm confused again, Allen. Why do you say that "the Hare" (the US) >>> thinks that refueling is too dangerous? >> >>Because when I asked an engineer working logistics at the Freedom program >>office why Freedom stationkeeping thrusters wouldn't be refueled in space >>he told me it was considered too dangerous. >> >>> refuel. The Freedom design, at least until Billary killed it, called >>> for either refuelling or complete changeout of propulsion modules. >> >>The plan was to bring the whole mdoule back. This is far more expensive >>then refueling. >> > Only if you assume something other that Shuttle will do the > refueling. I'd have liked to seen a backup fueling system in > case of Shuttle unavailability. However, since Freedom servicing > is (was) entirely Shuttleborne, there is no difference in cost > between a Shuttle refueling Freedom or a Shuttle replacing Freedom > thruster modules. You seem to be assuming fueling as a dedicated mission to arrive at the 'no difference in cost' conclusion. Either that, or you are assuming that an entire removable thruster module is not going to weigh any more or take up any more space than a large tank of fuel to fill it. I don't think either of those are good assumptions, hence replacing thruster modules rather than refueling them costs more (because you have t lift more weight and volume to accomplish the refueling in the replacement case, and hence can't carry something else that will have to be brought up or accomplished on another mission). > Replacement is safer, too. And since 1986, NASA has been under > de facto orders to do things the safest way possible. If an > astronaut were killed refueling Freedom, there'd be noises on > Earth about why NASA didn't do a safer module swap-out. If the > Shuttle is grounded and Freedom forced into free-drift for lack > of fuel, there'd be noises about why NASA didn't provide for > non-Shuttle refueling. In this no-win situation, I would opt for > the safest method too. And if the Shuttle is grounded and the station is forced into free-drift for lack of replacement thruster modules (which is the same thing as saying that it ran out of fuel), then where are you? It all comes down to just how much money and opportunity cost is a small incremental change in safety worth. It is this failure at rational risk analysis that has earned parts of NASA the poor reputation for performance and cost effectiveness that they have. -- "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. ------------------------------ End of Space Digest Volume 16 : Issue 224 ------------------------------