Space Digest Tue, 20 Jul 93 Volume 16 : Issue 896 Today's Topics: 3-man Shuttle EVAs 7/19/93 KSC News Release 7/19/93 NHQ News Release aerobraking manoeuvre Atlas A/C 104 Clementine Gaubatz talk on DC-X GPS in space (was Re: DC-1 & BDB) Hubble, Why the hurry? (3 msgs) Isp of solid fuels LRDPA & Return to the Mo Mars Direct Info Nitpicking Very basic questions about dark matter 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: 20 Jul 1993 00:04:30 GMT From: Dave Akin Subject: 3-man Shuttle EVAs Newsgroups: sci.space,sci.space.shuttle In article <2692@heimdall.sdrc.com> jeff findley, spfind@sgidq7.sdrc.com writes: >> Provisions are >> being made for 3-man EVAs, although there are no specific plans for any. > >What provisions are necessary for 3-man EVAs (besides carrying an extra suit)? >How exactly do they get those three guys into and out of that small airlock? >I know this has been done before, but I had problems getting the details of >*how* this is done. The basic problem is that there are only two servicing mounts for the EMUs in the airlock. In a typical EVA, the crew closes out the suits, checks the systems, goes through a prebreathe to get residual nitrogen out of the bloodstream, and depressurizes the airlock, all while using consumables from the orbiter via the suit umbilicals. They only go on internal consumables right before egressing, so they maximize their EVA time (around 8 hours without any reserves, typical EVAs rum between 6 and 7 maxed out.) One problem is that EV3 has to get dressed outside the airlock, due to a shortage of volume in the airlock (one of the IVA crew is in there too, helping EV1 and EV2 go through the checklists), and then enter the lock and breathe off internal consumables while the other two finish the pre-egress checklists on the umbilicals. Bottom line is that EV3 has about 1.5 hours less time outside than the other two. At the end of his nominal consumables, s/he comes in, hangs himself (or herself, of course) on the wall, and breathes off of the umbilical while the other two finish. There are also some complications on contingency procedures, and more work on suit recycling, but the biggest problem is sharing two umbilicals among three people, and the fact you're not getting the full time out of EV3. ------------------------------ Date: 19 Jul 93 14:42:00 +0600 From: Bill Loewy Subject: 7/19/93 KSC News Release Newsgroups: sci.space MISSION: STS-51 ACTS-TOS/ORFEUS-SPAS VEHICLE: Discovery/OV-103 ORBITAL ALTITUDE: 184 miles LOCATION: Pad 39-B INCLINATION: 28.45 degrees LAUNCH DATE: TBD CREW SIZE: 5 LAUNCH WINDOW: TBD EXPECTED KSC LANDING DATE/TIME: TBD EXPECTED MISSION DURATION: 8 days/22 hours + 1 day (an additional day on orbit may be granted if orbiter cryogenics and allow) IN WORK TODAY: * Troubleshooting of the ground pyrotechnic initiator controller * Argon servicing of the ORFEUS payload * Trickle charge on ACTS batteries WORK SCHEDULED: * Ordnance installation and reconnect operations * Load onboard cryogenic reactants * Aft engine compartment closeouts and aft confidence test * Final payload bay closeouts and close payload bay doors for flight WORK COMPLETED: * Open payload bay doors * Off load of onboard cryogenic tanks * Ordnance disconnect and safing operations * Remove mid-deck payloads for reservicing NOTE: Launch of the space shuttle Discovery on mission STS-51 was scrubbed Saturday at the T-20 minute mark due to a problem with a switch in the pyrotechnic initiator controller (PIC) which governs the pyrotechnic circuits on the Shuttle. The problem was narrowed down to a prematurely charged capacitor in the firing circuit of all eight Solid Rocket Booster hold down posts and the T-0 liquid hydrogen vent arm, located on the side of the external tank. This charge is normally initiated at the T-18 second mark. Work to repair the circuit, located on the mobile launcher platform, is now underway. A specific launch date has yet to be determined. NASA managers are discussing launch day options. The five members of astronaut crew departed for their homes in Houston on Saturday. Their schedule to return to KSC will be determined by the setting of a new launch date. The crew for this mission include: Commander Frank Culbertson, Pilot Bill Readdy, and Mission Specialists Jim Newman, Dan Bursch and Carl Walz. **END** ------------------------------ Date: 19 Jul 93 14:47:15 +0600 From: Bill Loewy Subject: 7/19/93 NHQ News Release Newsgroups: sci.space DAILY NEWS/TV SKED 7-19-93 Daily News Monday, July 19, 1993 Two Independence Square; Washington, D.C. % STS-51 launch delayed; % HST observations; % JSC Director to retire. Officials decided to scrub Space Shuttle's Discovery's STS-51 mission Saturday, July 17, at about 8:52 a.m. EDT because all eight of the solid rocket booster hold down bolts and the T-0 liquid hydrogen vent arm, located on the side of the external tank, were prematurely charged with current. This charge is normally initiated at the T-18 second mark in the countdown. Schedules have been made to drain the orbiter's fuel cell storage tanks and to disconnect or safe pyrotechnic initiator controllers in various areas of the vehicle and payload. Officials estimate this work will be completed today, allowing time to troubleshoot the pyrotechnic racks inside the mobile launcher platform. At this time, a new launch date has not been decided. * * * * * * * * * * * * * * * * Recent NASA Hubble Space Telescope (HST) observations indicate that a class of active galaxies further support the theory that they are fueled by a massive black hole at the center. This observation rules out vigorous star formation as the alternative explanation for the mysterious power source behind quasars and extremely bright galactic nuclei. Alexei V. Filippenko, Professor of Astronomy, University of California at Berkeley, states that "Our observations provide perhaps the most direct evidence to date that normal Seyfert galaxies and quasars are not powered by a burst of star formation." Filippenko further explained that the most likely alternative is the standard model in which the energy is provided by matter falling into a black hole. The Seyfert galaxies are nearby galaxies with extremely bright central regions that often obscure the much dimmer stars in the surrounding galaxy. Quasars are among the most distant objects in the universe and can be seen from earth because they are so bright. Seyfert and Quasars, collectively referred to as active galactic nuclei (AGN), give off a enormous amount of energy. A black hole is a theoretical object that is so compact its intense gravity prevents even light from escaping. In the standard model for AGNs , dust, gas and stars falling into the black hole heat up as they collide and release tremendous amounts of radiation. Previous HST observation have found additional circumstantial evidence for the presence of massive black holes in the core of active galaxies: dust disks, "light- cones" of ionizing radiation and extremely dense stellar concentrations consistent with theoretical models for the presence of a black hole. * * * * * * * * * * * * * * * * Johnson Space Center Director Aaron Cohen recently announced his retirement effective August 20. Cohen has accepted appointment as the Zachry Professor of Engineering at Texas A&M University. Paul J. Weitz, Deputy Director of the Johnson Space Center, will act as Director upon Cohen's departure. Cohen has more than 33 years of distinguished service with the government, 31 of those years with NASA. NASA Administrator Goldin said "Aaron represents all of the finest you can hope for in a government servant. His career and his accomplishments speak for themselves. He provides a benchmark. He has brought technical excellence, integrity, dedication and leadership to the Johnson Space Center and NASA. His career serves as an example to us all, and he leaves behind a lasting legacy." Goldin announced that Cohen will serve as Special Consultant to the Administrator on human flight as well as research technology along with his responsibilities at Texas A&M. * * * * * * * * * * * * * * * * Here's the broadcast schedule for Public Affairs events on NASA TV. Note that all events and times may change without notice and that all times listed are Eastern. Monday, July 19, 1993 noon NASA Today. 12:15 pm The Night Sky with Dr. Rich Terrile. 12:30 pm America's Wings. 1:00 pm Apollo 10 Sorting Out Unknowns. 1:30 pm Magenetic Effects In Space. 2:00 pm Starfinder #3. 2:30 pm Our Laboratories in Space. 3:00 pm TQM #3. Tuesday, July 20, 1993 noon NASA Today. 12:15 pm Aeronautics & Space Report. 12:30 pm Apollo 11 Anniversary/KISS: Apollo. 1:00 pm Apollo 11: For All Mankind. 1:30 pm Return to the Red Planet. 2:00 pm Starfinder #4. 2:30 pm Life on the Moon. 3:00 pm TQM #4. ------------------------------ Date: 20 Jul 93 03:13:50 GMT From: Samuel Mallinson Subject: aerobraking manoeuvre Newsgroups: sci.space Some time ago, there were some posts re: an aerobraking manoeuvre that was going to be attempted with a vehicle that was (then) orbiting Venus. My supervisors have performed some experiments involving aerobrake geometries and when I mentioned this to them, they said they would be interested to hear of the outcome of the Venus attempt. If anyone has a report, or a summary, or even a ftp server addres from which I may obtain the above, I would be most grateful if they could send it/them to me at: sam@maggie.me.adfa.oz.au or by post to: Sam Mallinson Dept Aerospace & Mechanical Engineering University College, UNSW, ADFA Canberra ACT 2601, Australia Thanks in advance. Sam Mallinson ------------------------------ Date: Tue, 20 Jul 93 01:49:39 GMT From: Dean Adams Subject: Atlas A/C 104 Newsgroups: sci.space Atlas Centaur 104, with a DSCS III bird onboard lifted off from the Cape today at 6:04 pm ET... it was a PERFECT launch! Its about time GD's luck turned around! ------------------------------ Date: 16 Jul 93 04:00:04 GMT From: David.Anderman@ofa123.fidonet.org Subject: Clementine Newsgroups: sci.space HS>In article <1214727f8@ofa123.fidonet.org> HS>David.Anderman@ofa123.fidonet.org writes: HS>>Clementine will orbit the moon next year, as part of a BMDO sensor HS>test, but is not *really* a lunar scientific mission... HS>Actually, it's not a bad lunar scientific mission, within its limits. HS> The major limit is that its sensors are not optimized for lunar HS>science except in small ways (like choice of filters). In particular, HS?it's a purely optical mission, with no gamma/neutron instruments. HS>-- I am told that it's optics are inferior to the normal NASA optics in several ways: sensitivity to radiation is high (meaning radiation in the space environment will tend to degrade the images) and the resolution is comparable to a Lunar Orbiter (as in the Lunar Orbiter from the 1960's). I am told that this is due to its unique mission (to test BMDO military sensors) - the optics are extremely small and light, but not to the normal NASA specs. I would love to be corrected on this - Clementine is a wonderful mission, but I don't want to get our hopes too high that this will be the Lunar Orbiter that we have all waited 21 years for. ___ WinQwk 2.0b#0 --- Maximus 2.01wb ------------------------------ Date: 20 Jul 1993 01:06:27 GMT From: "P. Douglas Reeder" Subject: Gaubatz talk on DC-X Newsgroups: sci.space In article <1993Jul13.061955.24064@wisipc.weizmann.ac.il> ward@agamit.wisdom.weizmann.ac.il (Ward Paul) writes: :In article <21om23$pot@scratchy.reed.edu> reeder@reed.edu (P. Douglas Reeder) writes: :> The software was written by a package called Matrix-X. :>Designers feed in equations and the package outputs Ada :>code, which is compiled without being further modified by :>humans, eliminating most of the need for testing, according :>to Dr. Gaubatz, and allowing a new version of flight :>software to be created in two days. : :Yipes! Please, please test your software. Since the input is some collection of equations, and the code produced is always for the same application, it seems likely that some theorums of provably-correct software have been applied. I suspect this is akin to changing the value of a constant in source code and re-compiling. For some program constants, within certain bounds (and assuming a program designed to allow this) one can do this with confidence that the result is as bug free as the last compile. However, I do not know the details. -- Doug Reeder Internet: reeder@reed.edu Div, Grad & Curl USENET: ...!tektronix!reed!reeder programming & derivative work I am actively seeking scientific programming contracts. ------------------------------ Date: 19 Jul 1993 21:39:48 -0400 From: Pat Subject: GPS in space (was Re: DC-1 & BDB) Newsgroups: sci.space In article <1993Jul19.145639.4746@mksol.dseg.ti.com> mccall@mksol.dseg.ti.com (fred j mccall 575-3539) writes: |In <229kmb$e5i@access.digex.net> prb@access.digex.net (Pat) writes: | | |>Reasons for a High Inclination Orbit : | |>1) Cheap Soviet flights available. | |That's not a valid reason unless you've already decided to chuck the |U.S. capability in this area in the interests of short-term monetary |savings. | It is possible to Take advantage of cheap soviet flights, without sacrificing US capabilities. If we swap to a high inclination orbit, it means we can swap some of the construction flights to the soviets, while flying other shuttle dependent missions, like SIRTF or KH-12 repairs, or LDEF 2-3 (Not that it's programmed). Besides, given the high probablity of a SHuttle Loss and Fleet shut-down, would you not want to be able to continue Logistics flights from somewhere? If we take Hurricane LeRoY, and it seriously screws up KSC for a couple months, it would be very useful to have an alternate launch site open. A high Inclination orbit, does not require we actually buy any russian flight services. it merely makes it possible. |>2) Improved Earth Observation Missions. | |This one actually makes sense, but the proponents of the |high-inclination orbit seem to hardly ever mention it or the actual |improvement that could reasonably be expected in return from it. | What can I say. THis is the one I hear a lot about. 51 degrees, just about doubles the earth observations science. >>3) Improved Logistics Flow missions. > >Unless this is just another way of stating something like 1, it >doesn't seem particularly obvious to me why this would be so. > It means, you have an opportunity for more flights in less time. KSC can only process N flights per year. Vandenburg does not launch to 28 degrees. Let's say SSF desperately needs a smoke shifter, a rapid launch from Pletkesk (sp) or baikonur is possible. It certainly is not from KSC. I doubt KSC could push a critical launch through in less then 30 days. If you are going to do some serious materials processing in Orbit, you want to get re-supply missions often. That means either some real big improvements at KSC and risk of single point failure, or the option to do launches out of several space-ports. >>4) Improved space science/engineering base. ( hihg inclination, >>is a far more rigorous environment then low inclination. > >This sounds like saying "We should do it this way because it is >*harder*." Somehow, that doesn't quite track for me. > You learn more about working to solve hard problems then easy problems. High Inclination acts as a driver towards STS getting the AL-LI ET and the ASRM, really not bad ideas in my book. High Inclination, means they work on radiation resistant systems. a interesting engineering problem. >>5) Apparently ACRV return is simplified( This is what i was told, >> I can't see an intuitive reason why this is). > Henry explained this one for me. thank you oh, lord of space lore. >>Make vs Buy is properly cognizant of the benefits of >>Technology developement. Nevertheless, Every company does >>Make this decision in it's business operations. > >Yes, and generally badly, since companies often fail to look at >anything too far beyond the next balance sheet. > Just because make vs buy is badly done, by most companies doesn't mean there is anything wrong with the process, it's a problem with the people. >>IBM Buys Micro-processors. DEC buys 4M DRAMS. > >Yes, and we can both see how healthy *those* two are, can't we? > WOuld they be healthier if they were pouring money into large IC Fabrication plants every year? DEC can't afford more then one large design project at a time, do you think they could do more after pouring money into a DRAM plant? And IBM used to do everything in-house, and it left them technologically adrift come the 80's. They had drifted so far from the main-stream they had no products to sell to the other electronics firms. The only way they could develope a PC, was to buy entirely from outside sources. >>Certainly there are intangible benefits from spooling up to >>do things, but if that bleeds off developemnt money from >>more vital activities, that is equally a problem. > >>Good Business people make these analyses. > Japanese companies have poured enormous amounts of money into low profit activities, it has left them in a very difficult position. It is somewhat un-certain if their gamble has paid off. > >>More energy Conservation, Higher energy taxes, developemnt of >>low energy consumption Infra-structure. It's bizarre, that it >>is cash wise cheaper for me to drive to Chicago then to >>take the train ( The absolute lowest energy cost solution. > >It's actually not, if you properly amortize the vehicle the way the >trains have to. This is one of the points of 'full costing' (in the >economic sense). Lots of people make bad decisions because they >figure that they already own the car so the cost of operating it >(other than gasoline) doesn't count. > Oh, I know. the actual full costing says take the bus, especially when pollution is factored in, but as an individual consumer, make vs buy, says it's cheaper for me to drive. -- God put me on this Earth to accomplish certain things. Right now, I am so far behind, I will never die. ------------------------------ Date: 19 Jul 93 17:01:04 From: Steinn Sigurdsson Subject: Hubble, Why the hurry? Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: In article monta@image.mit.edu (Peter Monta) writes: >So, naive question, but why aren't laser-interferometric gyros used? >With good diode lasers available, plasma-tube lifetime/fragility >would be moot. I believe diode lasers don't produce a sufficiently clean output to be used in orthodox laser gyros yet. And laser gyros qualified for combat aircraft don't need much improvement in durability to be good enough (in that department) for spaceflight. Hmm, "reliable sources" [ouch, I'm starting to sound like Allen], have told me that diode lasers are used in laser gyro designs, they won't tell me if the gyros are good enough to go into certain large US government payloads though, although from the context I gathered that was the whole point... on the other hand they could be still stuck to labtop assemblies for the high-precision needed in this case. In either case the HST design was frozen way before that kinda stuff was available... * Steinn Sigurdsson Lick Observatory * * steinly@lick.ucsc.edu "standard disclaimer" * * I can take the killing, I can take the slaughter * * But I don't talk to Sun reporters - B.B. 1983 * ------------------------------ Date: 20 Jul 1993 02:20:23 GMT From: Timothy Banks Subject: Hubble, Why the hurry? Newsgroups: sci.astro,sci.space henry@zoo.toronto.edu (Henry Spencer) writes: >I'm told that the Hubble gyros weren't particularly >advanced even by the standards of the time; there are better mechanical >gyros, never mind laser types. At a recent conference I went to, several of the presentations involved HST data. One of the speakers commented on the gyro problem, and said that they were "left overs from IUE". I'm afraid I haven't confirmed this... -- Timothy Banks, Physics Department, Victoria University of Wellington, NZ. bankst@kauri|rata|matai.vuw.ac.nz, banks@beagle|vavatch|solotol.phys.vuw.ac.nz "He's dead, Jim!" "OK, you take the tricorder, I'll take the wallet!" ------------------------------ Date: 20 Jul 93 03:33:51 GMT From: Pat Subject: Hubble, Why the hurry? Newsgroups: sci.astro,sci.space SPectrum magazine did a really interesting re-view of Laser Gyros and FOG's a few years back. From what I remember, Both of these, suffer from an in-sensitivity to small outputs. this is worked around by mechanically biasing the system, of course that undercuts a major elegance of optical gyros. I don't think the radiation problem is that bad, one could always shield the system, i just wonder if they are actually sensitive enough. although David's mention of planned replacements, seems to grant an answer. pat -- God put me on this Earth to accomplish certain things. Right now, I am so far behind, I will never die. ------------------------------ Date: 20 Jul 1993 00:29:23 GMT From: George William Herbert Subject: Isp of solid fuels Newsgroups: sci.space d9bertil@dtek.chalmers.se (Bertil Jonell) writes: > Does anybody know some typical specific impulses for solid rocket fuels, >both theoretical and practical? My references are mostly concerned with large >scale rocketry so they don't list anything lower than the Isp's for various >liquid propellant mixes. Hi Bertil; here's a quick table for optimum expansion 1000 PSI chamber pressure solid rockets Materials Isp SL, seconds --------- --------------- Galcit (asphalt/perch.) 240 perchlorate/plastic mixtures 270-275 Double-Base (nglycerine/ncell.) 270-280 SRB (perch./plastic/al) 283 This is off the top of my head, so I may have some detail errors. It's what I remember from the table in the Space Handbook, USAF University. Note that the SRB mixture, Ammonium Perchlorate in a plastic base with aluminum fuel added in, is standard in all launch vehicle large motors under varying names with slightly different characteristics. The Shuttle solid boosters, the Titan boosters, the Castor motors, the Arianne solid boosters, and the new Arianne 5 and H-2 boosters all use nearly the same mixture, and all get Isp around 280. -george william herbert Retro Aerospace ------------------------------ Date: 16 Jul 93 04:00:06 GMT From: David.Anderman@ofa123.fidonet.org Subject: LRDPA & Return to the Mo Newsgroups: sci.space DA>>The Lunar Resources Data Purchase Act, soon to be introduced in DA>Congress DA>>(fingers crossed) uses private vendors to supply NASA with a DA>geochemical DA>>lunar map. DA>>The LRDPA will pass the 103rd Congress if enough folks stop wishing DA>about a return to the Moon, and actually *do somthing* about it. BY>While LRDPA sounds like a good idea, I'm curious whether its BY>supporters actually believe that this will lead to a manned return to BY>the moon -- and if so, how? Well, I'm glad that you asked that question (typical response from a politician fishing for an answer to a tough question). 1) After 21 years of political gridlock, squabbling among scientists, and just plain idiocy, *any* lunar survey is a step in the right direction. If we delay too much longer in lunar exploration, the current generation of lunar scientists - those that cut their teeth on Apollo data - will fade away, leaving the next generation with no new data set to examine. Let's face it - how many grad students opt to be lunar scientists these days? A new lunar mission would go far in turning around the cultural state within the Beltway as to the chances for further lunar exploration, robotic and manned. As they say - the first step is the hardest. 2) The procurement method outlined in the bill will allow for more affordable exploration in the future, both robotic and unmanned. With enormous budget deficits looming down the road, unless we come up with affordable missions, we will have no missions. ___ WinQwk 2.0b#0 --- Maximus 2.01wb ------------------------------ Date: 20 Jul 1993 00:54:06 GMT From: George William Herbert Subject: Mars Direct Info Newsgroups: sci.space ralph.buttigieg@f635.n713.z3.fido.zeta.org.au (Ralph Buttigieg) writes: >Some of my BBS users would like to know more about Zubrin's Mars Direct >proposal. Are there any sites out there with articles, drawings etc? Failing >that, can anyone inform me of a contact address for Mr Zubrin? A E-Mail >address would be nice. I could then write to him and ask for permission to >make available some of his articles on the BBS. Zubrin isn't on the Net. He is, for internal Martin Marietta purposes only*, but not for outside email. And unfortunately I don't know of any versions of his papers online... which is _very_ unfortunate. That having been said, there are at least two of us here on sci.space (myself and Frank Crary) who've been following Mars Direct pretty closely for several years and who have seen the papers on it. It was (suprise) again a featured item at Case for Mars V earlier this year, and hasn't changed much except that Bob's talking more certainly about using artificial-G on the way out by tethering to the expended upper stage, or at least that's the impression I got. If you'd like to ask us questions about it, or have one of us do a summary article or something on the concept (and one should be posted here sometime, also one on the Stanford/Energia** proposal) we can work on that. -george william herbert Retro Aerospace * I have Bob Zubrin's snail mail address somewhere, and will email it to anyone who promises not to take too much of his very valuable time 8-) ** Prof. Bruce Lusignian of Stanford is primarily behind this one, a mission very similar to Mars Direct except not using in-situ resources (less risk) and using more NASAish costing estimates for the project. Uses the Energia launcher instead of a Shuttle-C concept (Mars Direct uses a shuttle-derived HLV named Aries). ------------------------------ Date: 16 Jul 93 04:00:08 GMT From: David.Anderman@ofa123.fidonet.org Subject: Nitpicking Newsgroups: sci.space BH>Nitpicking: Twenty, as of June 1993, since Explorer 49 orbited the BH>Moon. Much less if "we" are mankind, thanks to the Soviet Luna probes BH>and Hiten (launched 1/24/90). Thank you for the nitpicks. I believe Henry also caught me on these details. Actually, Explorer 49 was *not* a lunar probe in the usual sense: it literally ignored the Moon (that's why it worked). --- WinQwk 2.0b#0 --- Maximus 2.01wb ------------------------------ Date: 19 Jul 1993 21:42:59 -0400 From: Pat Subject: Very basic questions about dark matter Newsgroups: sci.space In article <1993Jul13.224833.1@fnalf.fnal.gov> higgins@fnalf.fnal.gov (Bill Higgins-- Beam Jockey) writes: >Remember a fundamental equation of cosmology: > >(Exotic explanations (Employment for > for = people > missing mass) like me) Does this mean, if we don't support your 12 Billion dollar SSC ( not very far from STS or SSF) you will actively lobby against our DC-X :-) pat -- God put me on this Earth to accomplish certain things. Right now, I am so far behind, I will never die. ------------------------------ Received: from VACATION.VENARI.CS.CMU.EDU by isu.isunet.edu (5.64/A/UX-2.01) id AA05179; Mon, 19 Jul 93 19:48:43 EDT Received: from CRABAPPLE.SRV.CS.CMU.EDU by VACATION.VENARI.CS.CMU.EDU id aa00123; 19 Jul 93 20:41:26 EDT To: bb-sci-space@CRABAPPLE.SRV.CS.CMU.EDU Xref: crabapple.srv.cs.cmu.edu sci.space:67276 Path: crabapple.srv.cs.cmu.edu!cantaloupe.srv.cs.cmu.edu!das-news.harvard.edu!noc.near.net!howland.reston.ans.net!usc!elroy.jpl.nasa.gov!ames!skates.gsfc.nasa.gov!stdvax.gsfc.nasa.gov!abdkw From: David Ward Newsgroups: sci.space Subject: Re: COOKIE CUUTTER PROBES (WA Date: 19 Jul 1993 19:11 EST Organization: Goddard Space Flight Center - Robotics Lab Lines: 68 Distribution: world Message-Id: <19JUL199319111897@stdvax.gsfc.nasa.gov> References: <742806263.AA02022@cheswicks.toadnet.org> <1993Jul16.124315.12953@infodev.cam.ac.uk> <1993Jul19.221909.3985@aristo.tau.ac.il> Nntp-Posting-Host: stdvax.gsfc.nasa.gov Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit News-Software: VAX/VMS VNEWS 1.4-b1 Sender: news@CRABAPPLE.SRV.CS.CMU.EDU Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU In article <1993Jul19.221909.3985@aristo.tau.ac.il>, zvikal@ccsg.tau.ac.il (Zvi Lev) writes... >Henry Spencer (henry@zoo.toronto.edu) wrote: > >: Who cares? Pick the one that's best at initial design time, and stick >: to it. It's not that vital to have the latest and fastest CPU aboard -- >: you're not running Microsoft software. :-) > >That is, of course, very true. However, I want to use it to bring up an >idea and see what people think about it: > >I want you to make me a personal computer, and it does not have to be faster >or more sophisticated than standard ones, except for the next few items: > >F. (and if E was a catch, this is a black hole!) - eh, sorry guys, >but I only want a few of these ever produced, say 5, and no, you cannot >use this technology to make anything that sells. > Of your reasons, I think this one's really the killer. As a matter of fact, if you get to 5 units, you might consider yourself lucky to have a "production line"-quantity unit. > >Actually, it is even worse - I do not believe that the software >of any spacecraft is anywhere as reliable as that of any old (5 years), >popular PC operating system. No matter how clever the people who test it >are, they are not cleverer than 10^7 users with crazy setups and uses. >The same for hardware, of course... > Agreed, but then you usually test the crazy setups and uses on a space program on the ground before you use it. Also, you generally don't have to tell a spacecraft's Flight Ops Team to Read the Manual (RTFM) very often. > >So, is there a way out? I dunno, but consider this: >suppose you could buy for around 100k$ a system which enables you to >fully build a sattelite main electronics system on something which is >PC compatible (no advertising intended. Could be any kind) - >that is, you can run on it anything a PC runs, plug into it any card >a PC can take. The system has all the excellent debugging >facilities you have for a PC, but with an operating system that also >supports some clever features such as redundancy, SEU protection, >ACS sensors/actuators support,etc. The thing also has a simulation >mode that can feed the desgined electronics/software inputs to match >a space enviro. > >I may be optimistic, but I think such a thing could solve many problems >for many many missions, if it is done correctly, with the right tradeoffs >between actual needs (mission,reliability) and the ever present >GEE WHIZ desire (lets develop a NEW way to do it that is 10% better than >the old one but costs double the money.. this should get us publicity...). > >Basically i guess I am saying that we might have a use for a space >hardware bus that runs Microsoft windows..... > FYI, Goddard's Engineering Directorate is currently building two spacecraft that use an 80386 microprocessor for main functions. No DOS or Windows though.:-) > >What are the opinions of my fellow USENET space advocates? >If you want to mail me directly - I'm >at zvikal@ccsg.tau.ac.il >Ever yours, >Zvi Lev > David W. @ GSFC ------------------------------ End of Space Digest Volume 16 : Issue 896