Date: Thu, 26 Nov 92 05:02:33 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #458 To: Space Digest Readers Precedence: bulk Space Digest Thu, 26 Nov 92 Volume 15 : Issue 458 Today's Topics: Computer synchronisation by GPS Evil wicked flying bombs! HST and management (was Re: Hubble's mirror) HST black hole pix? Hubble's mirror Magellan Update - 11/20/92 manned vs. unmanned spaceflight Shuttle Computer Problems Shuttle replacement (7 msgs) Space suit research? 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: Wed, 25 Nov 1992 19:23:24 GMT From: "Michael K. Heney" Subject: Computer synchronisation by GPS Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: > > [ GPS theory and practice ... ] >The usual sorts of synchronization protocols go to great lengths to deal >with the problem of *not* having a common absolute time reference. With >GPS, you *have* a common absolute time reference. All GPS receivers, >anywhere in the world, agree on the exact instant when the GPS system >clock reads 1:45:67.8727634 (with several more decimal places if the ^^^^^^^^^^^^^^^ When all GPS recievrs agree on that particular time, the system is broken! -- Mike Heney | Senior Systems Analyst and | Reach for the mheney@access.digex.com | Space Activist / Entrepreneur | Stars, eh? Kensington, MD (near DC) | * Will Work for Money * | ------------------------------ Date: Wed, 25 Nov 92 16:12:10 -0600 From: pgf@srl03.cacs.usl.edu (Phil G. Fraering) Subject: Evil wicked flying bombs! \>A range safety officer can blow up a Shuttle, not so with Delta Clipper. /Goodbye Disney World. A flying bomb with no destruct sequence isn't \acceptable. /Gary Personally, I kinda find the lack of an autodestruct on all those 747's to be unacceptable. My uncle John once opined that 18-wheelers would be driven much more safely if they were all wired up with an appropriate amount of semtex. Fine, you don't want to land it near Disney World? Fine. We put the spaceport someplace like West Texas. We'll probably have to anyway, since by then spaceflight may be against the Earth Protection Laws or some such nonsense ;-) Phil Fraering "...drag them, kicking and screaming, into the Century of the Fruitbat." <<- Terry Pratchett, _Reaper Man_ -- Phil Fraering "...drag them, kicking and screaming, into the Century of the Fruitbat." <<- Terry Pratchett, _Reaper Man_ ------------------------------ Date: 25 Nov 92 12:18:44 -0600 From: Bill Higgins-- Beam Jockey Subject: HST and management (was Re: Hubble's mirror) Newsgroups: sci.astro,sci.space In article <1992Nov25.091322.8953@news.Hawaii.Edu>, joe@montebello.soest.hawaii.edu (Joe Dellinger) writes: > In article <1992Nov16.033555.26144@murdoch.acc.Virginia.EDU>, gsh7w@fermi.clas.Virginia.EDU (Greg Hennessy) writes: > |> PE developed a system of testing that they > |> THOUGHT would be good enough. Unfortunately it was not. At least we > |> can be pretty sure that this blunder won't be repeated. > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > But... PE's system of testing WAS good enough. They had three > redundant tests, so that if one test gave a false OK the other > two could catch it. [...] > > The blunder was that the people paying for it weren't checking > over the shoulders of the ones being paid. Ah, but "the system was designed to work this way." NASA was trying to build an inherently expensive and high-performance system, the Space Telescope, as cheaply as possible, so they cut a lot of corners. In this case they kept the NASA staff supervising the project small and gave the contractors a lot of autonomy. People on the Net, and in the general press, often praise streamlined, low-paperwork project management... the popularity of the phrase "skunk-works" is one example. When it works, the results are wonderful and great value for the money. Fermilab's construction was supervised by a cowboy physicist, and his gang finished the Main Ring ahead of schedule and under budget. When it goes wrong, though, the risks of this approach become apparent. Hubble ran into big management troubles in the early Eighties, long before the mirror problem was detected. It was finished pretty much by throwing massive amounts of money at the problems, which negated the penny-pinching efforts of its early years and ended up costing way over a gigabuck by launch day. See Robert Smith's history *The Space Telescope*. (But wait a bit. It's coming out in paperback soon, in a revised post-launch, post-spherical- aberration edition which includes more Tales of Woe and Intrigue.) O~~* /_) ' / / /_/ ' , , ' ,_ _ \|/ - ~ -~~~~~~~~~~~/_) / / / / / / (_) (_) / / / _\~~~~~~~~~~~zap! / \ (_) (_) / | \ | | Bill Higgins Fermi National Accelerator Laboratory \ / Bitnet: HIGGINS@FNAL.BITNET - - Internet: HIGGINS@FNAL.FNAL.GOV ~ SPAN/Hepnet: 43011::HIGGINS ------------------------------ Date: Wed, 25 Nov 1992 18:19:30 GMT From: Henry Spencer Subject: HST black hole pix? Newsgroups: sci.space In article <1992Nov25.105202.4249@memstvx1.memst.edu> kebarnes@memstvx1.memst.edu writes: >Or, does anybody know where such a file could be obtained by >anonymous FTP? > >NASA? STSI? anyone?? NASA/STScI doesn't release HST images in digital form until after the one-year period allowed for the experimenters to publish papers on them. Occasional significant images do get released early for publicity, but only in hardcopy. (This policy is a bit silly, admittedly, in an age of cheap scanners...) Unless somebody's scanned it in, you're out of luck. -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Wed, 25 Nov 1992 19:23:37 GMT From: Henry Spencer Subject: Hubble's mirror Newsgroups: sci.astro,sci.space In article <83981@ut-emx.uucp> bill@bessel.as.utexas.edu (William H. Jefferys) writes: >#... three independent tests were run, and TWO OF THEM DETECTED >#THE ERROR. At which point, Perkin-Elmer management decided that the third >#was more trustworthy than the other two, and ignored the two failed tests. > >The tests to which you refer are the refractive null and >the inverse null, in addition to the faulty reflective null. >All three of them are based on the same basic interferometric >technology, and are not independent in the sense that I >meant... Okay, point taken -- more diversity in tests is desirable. However... >...Had they measured the position of >the field lens with a PLASTIC RULER, it would have been found. >There were lots of red flags flying, and they were all ignored. > >By an independent test, I meant a geometric-optics test such as a >Hartmann test that could have, fairly cheaply, detected the problem... Ah, but would it have been believed? That's the crucial problem. My impression is that it wasn't "we've got three similar tests, and the best one says we're okay", but rather "we've got three tests, and the best one says we're okay". The trick was not detecting the error -- after all, it *was* detected -- but detecting it in a way that would have been sufficiently emphatic and unmistakable to make P-E doubt their beautiful reflective null corrector. The point of an end-to-end imaging test, in this context, is not that it's an easy way to detect the problem, but that it's so hard to argue with. -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Wed, 25 Nov 92 19:22:43 GMT From: Doug Mohney Subject: Magellan Update - 11/20/92 Newsgroups: sci.space,sci.astro In article <2232@thoris.spc.yh.nec.co.jp>, hihara@tavia.spc.yh.nec.co.jp (hiroki hihara) writes: >We procured many parts from the United States for Hiten, and they >are proven to be strong enough against such environment. > >-- NEC Space Systems Development Division > Hiroki Hihara Can I quote you on that? :-) Play in the intelluctual sandbox of Usenet -- > SYSMGR@CADLAB.ENG.UMD.EDU < -- ------------------------------ Date: 25 Nov 1992 13:06:59 -0600 From: John David Regehr Subject: manned vs. unmanned spaceflight Newsgroups: sci.astro,sci.space Sorry if this is a dead subject, but I've only been reading this group for a week or so. I'm writing a paper contrasting manned and unmanned spaceflight. I'm in the middle of a couple of books, but I haven't been able to come up with a good thesis statement yet. I would appreciate hearing from people who have opinions on the subject, or who can suggest some good reference material. I am trying to approach this from a practical and philosophical standpoint, rather than detailing the historical controversy on whether the focus of space exploration should be on manned or unmanned flights. Thanks. ----------------------------------------------------------------------- John Regehr jregehr@matt.ksu.ksu.edu Kansas State University ----------------------------------------------------------------------- ------------------------------ Date: Wed, 25 Nov 92 22:04:01 GMT From: amon@elegabalus.cs.qub.ac.uk Subject: Shuttle Computer Problems I also had a few run-ins back in the late 70's that we basically figured were SEU's but never had any proof thereof. You probably know it already, but ceramic type chips have enough natural radioactive decay to cause more problems than most cosmic rays. Local beta decays cause a good bit of ionization, and the paths can be large enough to flip a bit. I have a file on this somewhere, although as I remember it is actually quite slim, ie I've not seen a whole lot published on the subject. I would expect that the people who really know are the ones at the national labs who tested components in high radiation environments of nuclear weapons tests. Probably all rather classified... Jordin??? ------------------------------ Date: 25 Nov 1992 11:55 CST From: wingo%cspara.decent@Fedex.Mfsc.Nasa.Gov Subject: Shuttle replacement Newsgroups: sci.space In article <1992Nov24.213130.20016@iti.org>, aws@iti.org (Allen W. Sherzer) writes... >In article vento@mars.lerc.nasa.gov (Dan Vento) writes: > >>> No, Spacelab and Astor are two payloads that we want very much to keep >>> in orbit so they can be used. >We want to bring back individual experiment racks. We don't want to bring >back the entire lab. > This is like saying we want to bring back the windshield wipers not the whole car after a rain. >>if not most of the Spacelab type payloads are very new concepts, flying for >>the first time, often built by organizations with little space hardware >>experience. Rethinking and reflight are part of the learning curve. > >Exactly. Those users are ill served by a Spacelab which flies one time >every couple of years. They WOULD be well served by something like >ISF which is up there all the time and so offers far more flight >opportunities. Nope ISF does not exist and therefore does not serve anyone. Spacelab has flown three times theis year and will fly at least that many times per year until SSF gets to PMC. SpaceHab also will be serving the microgravity material processing community starting on STS57 in April of 93. No Allan the shuttle is getting more and more viable as we work to drive down the costs of the experiments by using more and more commercial hardware that could never be flown on recoverable capsules. WE are flying a Macintosh II SI for a system controller for our experiment on SpaceHab I and II. We will also fly it on Spacelab SLS II next time. > >>Remember the Shuttle type small Space Experiments world (except for life >>sciences) has really only been around since the late 70's > >I hope you aren't referring to 'get away specials' since NASA doesn't fly >them anymore. > Hey Allan wake up. We have flown three here from UAH in the last 18 months and will fly five more in the next 18. There have been over 50 GAS payloads in the last 2 years and the que has just opened up for a new round. ------------------------------ Date: Wed, 25 Nov 1992 17:52:22 GMT From: Henry Spencer Subject: Shuttle replacement Newsgroups: sci.space In article jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins) writes: >There are ELVs with worse records that shuttle's, but I think there are also >a few with better records. A very few. The Saturns are the only ones that come to mind. The last few years haven't been good for expendable reliability records. >Actually, I'm not sure the shuttle has abort modes for the very first part of >flight and I know that most people don't consider certain abort modes >survivable. There is no officially-sanctioned abort mode while the SRBs are burning, last I heard. (Oh, you might try SRB jettison or orbiter/ET separation, but the orbiter won't survive either one.) It was looked at during early design, and again after Challenger; that is a *hard* problem. Once the SRBs burn out, you can try an RTLS (Return To Launch Site) abort, which is essentially a hypersonic U-turn, but the pilots consider it unsurvivable or nearly so. An alternative, also fairly unappealing, is to ride the orbiter down to low altitude and bail out into the Atlantic. There are times during post-SRB ascent when a multiple engine failure is unsurvivable, because the orbiter is too high and too slow and will hit atmosphere too hard. The first really attractive abort mode is the transAtlantic abort, with a landing in Spain or Africa. >[Soyuz] In fact, some of the >pictures I've seen seem to have escape rockets on unmanned payloads. Am I >mistaken or is there a reason for this? One doesn't normally put escape rockets on unmanned missions, because there's no point in incurring the hazard to the pad crews unless you're rescuing something important. A major exception is unmanned tests of hardware intended to be manned. A second exception is systems originally designed to be manned, in which the escape rocket's jettison sequence accomplishes something useful like pulling a payload shroud off. I believe the Progress freighters launch with an escape rocket for that reason. >>L-1011's flown in without elevator controls. United almost landed >>a DC-10 minus an engine and all controls. Convertibles have been landed. > >Convertibles? Do you fly them with the top down? He's referring, somewhat obscurely, to the Aloha Airlines accident where a 737 lost half the top of its fuselage and was landed safely. There have been one or two other less-dramatic incidents. >... DOE once did a test of the flammability of hydrogen and gasoline. >They filled two eight foot balloons with hydrogen gas and gasoline vapors >resectively and then fired tracers into them. The gasoline balloon ignited >immediately and exploded in all directions. It took three tracers to ignite >the hydrogen balloon which then burned upwards for thirty seconds without the >flames ever touching the ground. Most people don't realize that (a) half the people aboard the Hindenberg survived, and (b) many of the fatalities were due to the fall rather than the fire. If you look at the standard photograph, you see a big impressive ball of fire... billowing *upward*, away from the airship. -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Wed, 25 Nov 1992 16:18:48 GMT From: Gary Coffman Subject: Shuttle replacement Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: > >No, gliders don't burn on impact; they just go "crunch". It's still >just about as fatal. Actually it's not. The safety record for gliders is quite good, and they don't burn blocks of apartments on the ground when they do smack in like the *powered* Navy jet did in Marietta last year, or the *powered* C-130 that *burned* the hotel in Evansville did this year, or the Israeli jet freighter in the Netherlands. >Neither airliners nor rockets "pinwheel across the sky when a thrust >diverter fails". A Titan launch a few years ago had one of the core >engines lose gimbal control and lock in position (just about hard over >to one side, I believe it was); the other engine compensated and only >the technical crew noticed -- the launch was successful. But you mentioned *Harriers*, and *they* have lost thrust on one side and *have* pinwheeled, and *have* crashed and *burned*. Helicopters, another VTOL, also have lost tail rotors and spun into the ground. I've covered two such crashes in the last year. The pilots would probably have survived, if they hadn't *burned* to death. Airliners aren't VTOL aircraft, and rockets going *up* have room for a bobble in their course without smartly contacting the ground. Rockets coming *down* are an entirely different issue. An engine or control failure means a crash of a vehicle containing *rocket* fuel, perhaps miles from intended touchdown, like main street in Disney World for example. I'd feel a lot better if they landed these suckers at sea, far out at sea. And that's not a crazy idea. There have been proposals for sea launched and sea landed space vehicles. Sea Dragon comes to mind. Gary ------------------------------ Date: Wed, 25 Nov 1992 16:32:46 GMT From: Gary Coffman Subject: Shuttle replacement Newsgroups: sci.space In article <1992Nov24.151915.28177@iti.org> aws@iti.org (Allen W. Sherzer) writes: >In article <1992Nov24.062745.4287@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: >>That's the excuse used to abandon Saturn, Shuttle was supposed to be >>far cheaper. Classic mistake to abandon working hardware until flight >>proven replacements for the capabilities are in place. > >Would you consider a pickup truck which only worked one day a week and >cost $200 per mile to operate 'working hardware'? I wouldn't which is >why I don't consider Shuttle working hardware. When the only other available alternative is to stay home, yes I'd consider it working hardware. Deliver 50 out of 51 successful flights on different hardware with the same capabilities and lower cost, then we can talk about working hardware. >A range safety officer can blow up a Shuttle, not so with Delta Clipper. Goodbye Disney World. A flying bomb with no destruct sequence isn't acceptable. Gary ------------------------------ Date: Wed, 25 Nov 1992 18:15:34 GMT From: Henry Spencer Subject: Shuttle replacement Newsgroups: sci.space In article <25NOV199211262560@judy.uh.edu> wingo%cspara.decnet@Fedex.Msfc.Nas.Gov writes: >>>not a Shuttle problem per se. If you have to charge an entire Shuttle >>>mission against a satellite return, then it is expensive, >>To date it has never been done. Shuttle flights are so expensive >>that it isn't likely it can ever be done. You would need to return >>at least five or so satellites. > >I seem to remember several satellites that were returned and later launched >on other vehicles. Exactly two, and that mission was financially feasible only because NASA was itching to try it and gave the insurers a *very* good deal. It was worth doing once for the experience -- for one thing, we learned yet again that human hands are much more reliable than automatic machinery when you're doing more than just snapping pictures -- but could not be justified as an operational (as opposed to experimental) mission. >Also there was LDEF that is contributing greatly to >lowering the cost of all of the other spaceflight missions due to the >information gathered about the effects of materials in a long term LEO... As Allen has pointed out, we'd have been better off flying several smaller LDEFs over varying periods. Some of the LDEF experiments were completely ruined by being in space *too* long. (For that matter, before you get too enthusiastic about LDEF, please bear in mind that (a) it was meant to be reflown several times for varying periods and (b) it was meant as a general-purpose way to fly cheap experiments, and it has not met either of those hopes and never will. The undeniably- useful information from LDEF is being had by sifting the ashes of the original mission plans.) Nobody denies that returning things from space is useful now and then in small amounts, but bringing back (say) one LDEF pallet at a time is not difficult without the shuttle. >>... if your in a Delta >>Clipper made of much simpler components (less likely to fail) and with >>abort modes throughout the entire flight envelope it is a great deal >>of comfort. > >Uh this is kinda strange when you think of all of the complex piping and >fittings and multiple engines on the bird. Seem to me that there is more >of a chance of a random or otherwise failure. Of course, if you're flying in a Delta Clipper, it has been test-flown before you were allowed on board. (That *same* vehicle has been tested, not just the general design.) A 747 is considerably more complex than a Delta; it is also considerably more reliable, because it can be tested. >One good aspect of this is that >DC is robust enough to compensate for the failure, unless they miswire the >controllers like they did on the first Saturn V flight. It was the second Saturn V flight, and note that the Saturn V survived it and a DC probably would too... >>A range safety officer can blow up a Shuttle, not so with Delta Clipper. > >Hate to bust your bubble on this one but on ANY launch from ANY facility >operated by the US government, range safety can push the boom button whenever >they see the mission deviating sufficiently from its mission parameters. DC >will not be an exception for this. This is one reason why operational DCs would not fly from US government missile ranges. (There are lots of others, like enormous bureaucracies, stupid regulations, and massive costs.) The FAA does not require or permit range-safety charges aboard airliners -- yes, even when they fly from airport facilities operated by the US government -- and DC-1 will not be an exception for *this*. Yes, McDD has talked to the FAA about certifying the DC-1 as an airliner, and last I heard, the FAA was interested and cautiously willing. -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Wed, 25 Nov 1992 19:27:40 GMT From: "Allen W. Sherzer" Subject: Shuttle replacement Newsgroups: sci.space In article <25NOV199211262560@judy.uh.edu> wingo%cspara.decnet@Fedex.Msfc.Nas.Gov writes: >Allan, dost thou have a reference for your "multibillion dollar" statement. Spacelab alone cost $1B. Add in the cost of Astro plus flights and other work and we are talking billions. >>The experimental community doesn't pay for them so this should come >>as no suprise. >The experimental community does pay for the instruments in the spacelab, and >they also put several years of their lives into the effort. We where talking about launches. The experimental community doesn't pay for launches. Do you think the Italians would have paid the hundreds of millions in actual cost for their payload launch in the last Shuttle flight? I think they would have said 'hell no' and launched on a Pegasus for an order of magnitude less $$. Now if NASA goes ahead with the authorized voucher program, we may see this change. >>To date it has never been done. Shuttle flights are so expensive >>that it isn't likely it can ever be done. You would need to return >>at least five or so satellites. >I seem to remember several satellites that were returned and later launched >on other vehicles. You are referring to the two Palpa communication satellites. It was about all the Shuttle could do and it cost the taxpayers hundreds of millions in launch subsidies. We spent half a billion $$ to recover $75 million worth of satellites. Only a NASA employee could consider that a good deal. >Also there was LDEF that is contributing greatly to >lowering the cost of all of the other spaceflight missions due to the >information gathered ERROR: You are assuming LDEF as is was the one and only way to get this infromation. This is incorrect. >you this is not figured in Allans accounting but it is in mine where my >reliablity is greater for the information. If you read my stuff in the past you will see I do include recovery of LDEF type payloads. I simply do it in a different (and much cheaper) way. >>>>A Titan IV launch costs about a third of what a Shuttle flight costs. >Last I heard Titan IV flights were $281 million according to Space Week. That is including a Centaur upper stage. Configured in a similar manner the cost is about a third. >Your >own figures Allan put the Shuttle cost at $500 million per flight. Take a >look at the fraction, its kinda closer to 1.8 to 1. Even if true, so what? We are still talking about a factor of 2 cost difference. If your goal is to keep us all on the ground, by all means buy the expensive one. On the other hand, if you want to open up the space frontier, you got to reduce costs. Which are you Dennis? >>So? When a Titan goes boom the crew has a very good chance of surviving. >Not so the Titan that blew up about 100 ft above the pad a few years ago. >There was zero warning, the SRB's just went poof Still a good chance of survival. All the pilot needs is 1/2 a second to hit the button (rest assured his hand would have already been on it). >>When Shuttle goes boom on the other hand, people die. >yep its called the cost of doing business Agreed. But that doesn't change the fact that capsules are safer than Shuttle. >>Would you consider a pickup truck which only worked one day a week and >>cost $200 per mile to operate 'working hardware'? I wouldn't which is >>why I don't consider Shuttle working hardware. >We are not talking about pickup trucks It's called an analogy. If you don't know what that is or can't deal with it, then remove this part of the thread. Otherwise tell us all if you think the truck works. >>If your in Shuttle, true enough. On the other hand if your in a Delta >>Clipper made of much simpler components (less likely to fail) and with >>abort modes throughout the entire flight envelope it is a great deal >>of comfort. >Uh this is kinda strange when you think of all of the complex piping and >fittings and multiple engines on the bird. Compared to what? DC has fewer engines than Shuttle and needs less to support them. Hell, even the DC RCS uses the same fuel as the main engine! Not only does Shuttle have more engines, but it has four different types of engines. Shuttle supporters who think DC is complex should go back to engineering school. >DC is robust enough to compensate for the failure, unless they miswire the >controllers like they did on the first Saturn V flight. Delta Clipper is fully reusable. That means it isn't likely the controller was miswired. If it was miswired, the DC couldn't have flown to the spaceport. DC is no more complex than a 747. 747 techs rarely mess up the hardware. >>A range safety officer can blow up a Shuttle, not so with Delta Clipper. >Hate to bust your bubble on this one but on ANY launch from ANY facility >operated by the US government, range safety can push the boom button whenever >they see the mission deviating sufficiently from its mission parameters. DC >will not be an exception for this. DC-X will have charges. DC-Y may have charges but DC-1 will not have charges. It won't need them any more than airliners need them. You got to change your mindset Dennis. You won't make it as long as you continue to equate more money and more complexity with better. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------150 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: Wed, 25 Nov 1992 19:36:06 GMT From: "Allen W. Sherzer" Subject: Shuttle replacement Newsgroups: sci.space In article <25NOV199211554486@judy.uh.edu> wingo%cspara.decent@Fedex.Mfsc.Nasa.Gov writes: >>>> No, Spacelab and Astor are two payloads that we want very much to keep >>>> in orbit so they can be used. >>We want to bring back individual experiment racks. We don't want to bring >>back the entire lab. >This is like saying we want to bring back the windshield wipers not the whole >car after a rain. Your getting confused. A car is a transportation device. A lab isn't. A car *was designed* to move. Lab's aren't. When I go home from work, I bring whatever papers I need and maybe a book or two. I don't bring back my entire lab. If I did, I would need a much larger and far more expensive car to go home in. Special roads would need to be built just for me and it would be very very expensive. Worse, my co-workers could only use the lab when I saw fit to bring it back to work. This is why I prefer to keep my lab where it is. I can only wonder why you feel the need to reduce productivity and increase costs by dragging it everywhere and preventing others from using it. >Nope ISF does not exist and therefore does not serve anyone. You know, I'll bet that if somebody said that Freedom does not exist and therefore does not serve anyone you would disagree. >the shuttle is getting more and more viable as we work to drive down the >costs Care to document any cost savings? Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------150 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: 25 Nov 92 17:46:05 GMT From: "Charles R. Martin" Subject: Space suit research? Newsgroups: sci.space In article <1992Nov25.044543.25078@ucsu.Colorado.EDU> fcrary@ucsu.Colorado.EDU (Frank Crary) writes: In article <17722@mindlink.bc.ca> Bruce_Dunn@mindlink.bc.ca (Bruce Dunn) writes: >> Apparently anything significantly below 3 psi partial pressure of oxygen >> is a potential health risk, unless you have many generations of ancestors >> who lived in the mountains. I'm not sure what you mean by "significantly", but this certainly doesn't apply to ~2 to 2.5 psi oxygen: The residents of Aspen, many (most?) of whom have zero generations of ancestors who lived in mountains, live and work at such oxygen pressures, with no visable problems. Further, people with no hereditary _or_ personal adjustment to low pressures routinely go they to ski (which, if anything, requires slightly above normal consumption of oxygen.) Frank -- Bop down the hall and talk to Igor Gamow (and give him my regards -- it'll confuse the hell out of him since I was a student of his Many Years Ago). Anyway, actually a significant number of people develop altitude sickness even at Aspen and *lower* altitudes. Growing up in Alamosa, I know there were people there who never adapted and had to leave for medical reasons even though they were to all appearances healthy; Robert Heinlein's wife Ginny had altitude sickness in Colorado Springs that eventually forced their move to California. -- Charles R. Martin/(Charlie)/martinc@cs.unc.edu Dept. of Computer Science/CB #3175 UNC-CH/Chapel Hill, NC 27599-3175 3611 University Dr #13M/Durham, NC 27707/(919) 419 1754 "Oh God, please help me be civil in tongue, pure in thought, and able to resist the temptation to laugh uncontrollably. Amen." -- Rob T ------------------------------ End of Space Digest Volume 15 : Issue 458 ------------------------------