Date: Thu, 25 Mar 93 05:42:37 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #365 To: Space Digest Readers Precedence: bulk Space Digest Thu, 25 Mar 93 Volume 16 : Issue 365 Today's Topics: Al to isometric crystalline C..diamond Dallas Boring Snooze Flame Derby (was Re: Luddites in space) How to cool Venus Rocket clones: reduce risk of introducing new tech SSF_REdesign Water Simulations Water Simulations (Was Re: Response to various attacks on SSF) Why use AC at 20kHz for SSF Power? 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: 24 Mar 93 22:44:08 GMT From: hathaway@stsci.edu Subject: Newsgroups: sci.astro,sci.physics,sci.space In article <21MAR199318484461@erich.triumf.ca>, music@erich.triumf.ca (FRED W. BACH) writes: > In article <1993Mar20.210235.29098@news.columbia.edu>, mnd@cunixb.cc.columbia.edu (Mohib N Durrani) writes... > > [ a lot of really intense stuff deleted ] > > # Look For The CRESCENT MOON ( HILAL ), --- >>> ) > # It Is One Of THE MOST BEAUTIFUL OF CREATIONS; ---- >>>> ) > # Then Offer An INTENSE PRAYER To The ONE CREATOR, ---- >>>> ) > # All Sincere DEVOTIONS Are Surely ACCEPTED. --- >>> ) > On Monday afternoon (in Maryland) I heard on the radio a report that an announcement came from Saudi Arabia that the crescent moon _had_ been sighted (evening had fallen in that part of the world). The radio also said that since it had NOT been sighted that evening in Iran (futher east), those there will continue to observe Ramadan for (at least) one more day. However, my references say that New Moon had not even occurred until later Mon night/Tues morn (MAR 23 07:14 UT), and Ottwell's book said that sighting of the crescent would be very unlikely in the eastern US even on Tuesday night. I think this was consistent with the original posting (now vaporised on my system). So how can it be sighted a whole day earlier even further east? Has anyone else heard of such announcements and whether they were officially accepted or retracted or if not, how did they move the moon around? Although I believe this method of calling months (CALendar stuff) is mostly arbitrary, so it doesn't really matter much to non-followers of the tradition, if such rules are used, why are they not done in a consistent manner? Or was the report just a mistake by the radio station? If so, perhaps we need more education for the media. Just curious, Wm. Hathaway Baltimore MD ------------------------------ Date: Thu, 25 Mar 1993 03:16:48 GMT From: Donald Lindsay Subject: Al to isometric crystalline C..diamond Newsgroups: sci.space WHITEMAN%IPFWVM@UICVM.UIC.EDU ("S.K. Whiteman") writes: > to artificial diamonds. I was wondering if > there has been any technical info available on this > topic. Scientific American covered this in the last year or so. Since then, there have been various announcements .. like the people who sell molded diamond. -- Don D.C.Lindsay Carnegie Mellon Computer Science ------------------------------ Date: Wed, 24 Mar 1993 20:03:52 GMT From: Dillon Pyron Subject: Dallas Boring Snooze Newsgroups: sci.space For those of you in the Dallas area, or who (foolishly) read the Snooze (aka Dallas Morning News), check out the Wed. TODAY section. I've already called, they are both mortified and concerned, since their sources indicate the information was correct: A graphic on the progress of women shows 1978 - Sally Ride is the first woman in space -- Dillon Pyron | The opinions expressed are those of the TI/DSEG Lewisville VAX Support | sender unless otherwise stated. (214)462-3556 (when I'm here) | (214)492-4656 (when I'm home) |God gave us weather so we wouldn't complain pyron@skndiv.dseg.ti.com |about other things. PADI DM-54909 | ------------------------------ Date: 24 Mar 93 12:57:01 From: Steinn Sigurdsson Subject: Flame Derby (was Re: Luddites in space) Newsgroups: sci.space,talk.politics.space In article <1993Mar24.091928.1@fnalf.fnal.gov> higgins@fnalf.fnal.gov (Bill Higgins-- Beam Jockey) writes: In article <1op22q$5qf@agate.berkeley.edu>, gwh@soda.berkeley.edu (George William Herbert) writes: > Nick: hold your breath for a minute and don't post anything tomorrow. > Dennis: hold your breath for a minute and don't post anything tomorrow. > You two are both smart enough not to have to get into flame wars every > few months... Maybe they should both take a break and gang up on Allen. What do you think, George, are pat and Steinn promising new contenders in the Flame Derby? Eek, and here I've been holding my breath for a whole day now! Definitely time to stop - no point anyway, I can never equal the ideological purity of previous champions ;-) | Steinn Sigurdsson |I saw two shooting stars last night | | Lick Observatory |I wished on them but they were only satellites | | steinly@lick.ucsc.edu |Is it wrong to wish on space hardware? | | "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 | ------------------------------ Date: Wed, 24 Mar 1993 19:07:11 GMT From: James Davis Nicoll Subject: How to cool Venus Newsgroups: sci.space Could one of the thermodynamics-literate people on the net make a guesstimate as to how long it would take for the the Venerian atmosphere to cool enough so that the various components of the atmosphere liquified/ solidified, given a sudden lack of illumination from the sun? I have a gut feeling it would take an inconvenient amount of time for Venus to cool, but I trust math over gut feelings. In article <1993Mar24.141613.6149@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: > Trying for an intermediate yield, between the Soviet bomb and the Sun, >presents formidable technical challenges. Now, that's sig.file fodder. James Nicoll ------------------------------ Date: 24 Mar 93 22:47:55 GMT From: Henry Spencer Subject: Rocket clones: reduce risk of introducing new tech Newsgroups: sci.space In article <1993Mar24.151947.6663@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: >>As witness Pegasus, it *is* possible to create a new payload class with >>a new launcher. > >Scout, and Ariane multiple satellite launch systems, had already created >the Pegasus payload class... Then why weren't any being launched? The number of *small* satellites carried up on Ariane to date can be counted on your fingers, and the number of launches carrying them can be counted on your thumbs. Scout is moribund if not dead. Pegasus's order backlog already exceeds the total number of such payloads flown in the last decade. When people plan for such missions, the nominal launcher is almost invariably Pegasus. Once in a while somebody mentions Scout. Launch opportunities for small payloads on Ariane are scarce as hen's teeth. It was Pegasus that made this payload class real. -- All work is one man's work. | Henry Spencer @ U of Toronto Zoology - Kipling | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 24 Mar 1993 14:15 EST From: "David B. Mckissock" Subject: SSF_REdesign Newsgroups: sci.space In article <31631339@ofa123.fidonet.org>, Wales.Larrison@ofa123.fidonet.org writes... > Max Faget and Joe Allen of SII were 2 of the first people >named to the Shea group looking at SSF re-design. Are you sure Joe Allen is a member of the team? The list floating around headquarters has four non-NASA / non-International Partner folks on the SSF re-design team: Mr. Mike Mott Dr. Max Faget Adm. Tom Betterton Mr. Ed Nowinski Everybody knows Faget, but some of us are in the dark about where the other three guys came from (a search in the copy of "Who's Who" in the library didn't turn up anything). ------------------------------ Date: 24 Mar 1993 15:46 EST From: "David B. Mckissock" Subject: Water Simulations Newsgroups: sci.space In article <1993Mar17.175450.27423@iti.org>, aws@iti.org (Allen W. Sherzer) writes... >I think water tanks and practicing on them is >a great idea. However, to assume that we can corelate actions in >the tank to the actions needed to assemble a large space structure >(like Freedom) in free fall is foolish. > >The bottom line remains that we have nowhere near the EVA >experience base to practice any but the most simple EVA activities >with any degree of confidence. and, Dennis had written: >>The primary problem that was faced on the Intelsat mission is >>that the tank simply cannot accurately mimic the moments of >>inertia of large structures in orbit. To which Allen brilliantly responds with: >You mean like space stations? Congrats Dennis, you have found a >problem with Freedom construction: the tanks cannot provide a >suitable simulation for the construction of Fred. I guess Allen's thought process is: "Fred is very big. Fred is made up of lots of big pieces. Intelsat was big. The astronauts had problems grabbing Intelsat. Ergo, astronauts will have problems assembling Fred. NASA, in its typical stupidity, does not see the obvious connection between big things, like Intelsat and Fred and, compounding our stupidness, we don't realize that you can't mimic the moments of inertia of large structures in water tanks." Two points come to mind: #1 The Canadian Mobile Servicing System (MSS) In case you have forgotten, CSA is developing the MSS for Fred. NASA considers the MSS part of our "critical path," which means that it is an indespensable part of the assembly and maintenance procedures for SSF. The MSS includes a robotic arm (SSRMS, Space Station Remote Manipulator System), which, in conjunction with the Shuttle arm, is used to assemble the 'big' parts of SSF (like the modules & the PIT truss segments). SSF is *NOT* constructed with crewmembers moving by hand things like the 27 foot (8.4 meter), 35,600 pound (16,148 kg) hab module. Let's walk through the on-orbit installation of the HAB. Shuttle launches with the HAB in the bay, Orbiter docks with SSF. Bay doors open, Shuttle arm used to take the HAB out of the bay. Shuttle arm hands off the HAB to the Station arm. Station arm plugs the HAB into Node 1. Astronaut goes EVA, inspects the mated joint, returns to the inside. HAB Assembly complete. My my, we have a real complicated EVA procedure there, don't we? #2 Astronauts participate in the tank tests. When we practise the EVA's in the water tanks at JSC & MSFC, we don't just sign-up divers from the local diving club. We utilize astronauts, who HAVE ON-ORBIT EVA EXPERIENCE. Thus, we are asking somebody who "has been there" to gauge the acceptability of our suggested EVA tasks. This is a key point. At the sub-team meetings for the WP-04 CDR that occured late last month, representatives from the astronaut office were in attendance to defend the Review Item Discrepancies (RIDs, in NASA-ease) written by their organization. I sat in when several of their RIDs were discussed in detail in the Operations sub-team. To give you examples of their issues, they were concerned with the susceptability of the solar array mast cannister to accidental EVA kick-loads (the idea is an astronaut might accidently kick a hole in the side of the cannister), they noted that one of our contingency EVA procedures required a tool to operate longer than it's spec value (a word in our defense, nobody had told us the spec value for the tool), they worried about interference with cable bundles, because a drawing showed a cable bundle near an EVA translation path. All-in-all, they probably wrote 100 or so RIDs, and not *ONE* of them said anything about your apparent favorite issue, namely, that we aren't doing any on-orbit testing with WP-4 hardware to verify the EVA procedures. Also, just to note how important NASA considers the opinions of the crew, a representative from the astronaut office had a seat at the WP-04 Critical Design Review board. Summary On the one hand, I have the crew office providing detailed RIDs listing their concerns regarding our EVA procedures, and these RIDs contain no mention of a "problem" relative to the lack of on-orbit tests to verify the EVA procedures. On the other hand, I have Allen Sherzer venting his spleen on how stupid NASA is since we don't see the obvious need for these on-orbit tests. The bottom line is, how credible are the water tank tests at predicting the ability to perform the proposed SSF EVA tasks on-orbit? Allen's answer is that the tank tests are a lousy predictor of the feasibility of successfully performing the EVA procedure on-orbit. The astronaut office, the group responsible for performing the EVA tasks, says the tests are a credible predictor. Unless Allen is a former astronaut with both water tank and on-orbit EVA experience who subsequently changed his name, I'll believe the astronaut office. ------------------------------ Date: Wed, 24 Mar 1993 16:27:20 GMT From: Frank Crary Subject: Water Simulations (Was Re: Response to various attacks on SSF) Newsgroups: sci.space In article <1onsgi$qee@access.digex.com> prb@access.digex.com (Pat) writes: >I saw some old Air FOrce/ NASA footage on the old skin suits. >The fabric looked real hokey, and the NASA PM for suit technology >claimed it could only achieve 1.5 psi, and they needed 5, >so it was a triple suit. >Now with new spandex, could a single layer produce between >3-5 lbs counterpressure? Almost certainly, but material strengths might not be the only reason for using 1.5 psi layers: Putting the suit on was apparently a problem. It required alot of strenght, pushing and pulling to get into a suit stretched to 1.5 psi... Getting into a 5 psi one would be much worse, and it's possible three, 1.5-psi layers would simply be easier to get into. Three layers is also more damage resistant. (By the way, the current inclination if for 8.5 psi suits, to avoid pre-breath...) By the way, the idea of using some sort of compressable foam layer to equalize pressure (e.g. around joints) sounds promising: It would certainly make for a clumsier suit, but perhaps not as clumsy as one with pressurized joints. Frank Crary CU Boulder ------------------------------ Date: Wed, 24 Mar 1993 18:01:40 GMT From: fred j mccall 575-3539 Subject: Why use AC at 20kHz for SSF Power? Newsgroups: sci.space In <1odsv9INNpvs@access.digex.com> prb@access.digex.com (Pat) writes: >In article steinly@topaz.ucsc.edu (Steinn Sigurdsson) writes: >>In article schumach@convex.com (Richard A. Schumacher) writes: >> >> >> Oh, nuts. So a 20kHz power system saves 2,000 pounds, huh? >> Assume it costs $3,000 per pound to launch. Spend $6M on >> the extra weight of a 400 Hz system, and 20 minutes later >> >>If it were to become standard and used on other systems >If the idea were so hot, then it would be used on other areas. >The only thing I see Utility power generation moving towards is >Higher Voltage. 208/480 three phase is now getting pushed back >by 5-7KV systems for campus distribution. Utility power has always used HV lines for distribution. Of course, they also have to 'wheel' at each state border, too. Yep, that's how we should do it everywhere else, all right, cuz that's how it's always been done. Yup. >>it would save a lot more weight in the long run. >There were never plans to ever expand SSF beyonf the >EMCC Eight Man Crew COnfig, and that was based upon >very speculative budgeting. >>When you're about to put up the first major piece >>of infrastructure in space, one that might in principle be >>expanded, it becomes sensible to consider the possibility of >>whether a new standard for such things as power systems makes >>sense in the long run. >You mean, the way most things are built upon previous knowledge base? >Gee stein, you seem real positive over this technology, >why don't you go and build some lab equipment that pulls this >as prime power. >>One of the most frequent complaints here against NASA is that >>they don't consider new technologies that might lower costs >>in the long run and don't experiment with different concepts. >Yet, by the figures presented in the paper, which put >only the most positive glow on 20KHz power, we seee only a >6 Million weight savings and a claimed 150MIllion dollar lifecycle >savings. if we take the money saved on designing this idea, and put >it in the bank, i bet we'd be looking at lifecycle savings of >more then that. Someone else already made the appropriate response to this one. Gee, we should have just banked what Columbus spent. >>Yet, when they do and it doesn't work out they are chastised >>(often by the same people) for wasting money when they could >>have been using old and tried technology, and using the >>magic of 20-20 hindsight it becomes "obvious" that the >>new concept tried wouldn't work. >If they had a solid disciplined engineering developement program >to prove and test all this gear,Id believe it, to be worth >exploring, but to go out on a tremendous technological limb >on an untried technology on the most expensive NASA program this >Decade, maybe even century, is just plain rank foolishness. The more you talk the less convinced I am that you know anything about engineering, Pat. >> >> As for the difficulty of shielding scientific instruments >> from 400 Hz noise: some EE better go tell those poor >> fool astronomers who have been flying their instruments >> in U-2s for 20 years that they're doing it all wrong... >> (Oh no! Now they're doing the same thing in an SR-71! >> Stop them before it's too late!) >> >>Those instruments are handbuilt at no small expense. >No doubt, smaller then that for 20KHz. Aren't most scientific >devices hand built? if it was production gear, you'd get it at toys R us >and lots of stuff is production built for 400KHz. Radars, computers, >Motors, generators, Power conditioners, Lights, Fans, Air conditioners, >circuit breakers.... >None of that stuff is available for 20KHz. >> >> 20kHz power is a Boondoggle. A gold-plated, aerospace- >> contractor's-wetdream, engineering-porkbarrel boondoggle. >> >>Yeah right, NASA should just stick with old and tried concepts, >>tie swans to balloons, or use large cannon and capsules lit >>with gas lamps. And people wonder why NASA has become afraid >>to take risks and run experimental missions... >> >Careful stein, you are listening to nick and it's rubbing off. >Actually my simple acid test on 20KHz, is why Boeing doesn't use it. >If resonant inversion was such an efficient method, and the weight >savings were so high on motors, etc, then 747's would be converted >over to this standard, or new boeing hardware would use this. >Aircraft are very weight conscious, probably more so then Rockets. >Airlines make money running packed to the gills, running with 80% >load, is a fast way to lose money. some airlines need to carry 93% >of cargo, to even break even on a route. it depends on schedules >and fares. >I once read, that a 1 pound savings on a 747, translates to a 10,000 >dollar savings. now this was when fuel was high, and god, that's >a real dusty memeory, but It does seem illustrative. >Commercial aviation is very weight conscious. Military are even more, >yet none of these guys have ever looked at this, to my knowledge, >and boeing is very cash rich, and the AF spent 10 years with money >as no object. But not nearly as weight conscious as spacecraft have to be. In addition, needs are somewhat different between an aircraft and a space station. Personally, I think 20kHz was a bad idea, but I also think that this insistence of yours that if it was good enough for the Wright brothers it's good enough for SSF is just a bit silly. -- "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 365 ------------------------------