Date: Wed, 25 Nov 92 05:04:40 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #454 To: Space Digest Readers Precedence: bulk Space Digest Wed, 25 Nov 92 Volume 15 : Issue 454 Today's Topics: Computer synchronisation by GPS (2 msgs) GAS GPS handheld receivers (3 msgs) Pumpless Liquid Rocket? Russian Photon capsule lands in Pacific & comes to Seattle Safe, cheap hypergolics (was Re: Pumpless Liquid Rocket?) Scientific method shuttle payload limits Shuttle replacement (8 msgs) Spaceborne Artificial Intelligence, Anyone? 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 Nov 92 16:09:53 GMT From: Dave Hopkins Subject: Computer synchronisation by GPS Newsgroups: sci.space As I understand it GPS has a number of accurate (atomic) clocks which are fundamental to determining ones position. One of the quoted applications for GPS is for synchronising computer systems across the world using this time information. How would such a system work and what advantages would this offer over conventional handshaking techniques? Dave Hopkins ------------------------------ Date: Tue, 24 Nov 1992 21:21:54 GMT From: Henry Spencer Subject: Computer synchronisation by GPS Newsgroups: sci.space In article dhopkins@gpsemi.lincoln.com (Dave Hopkins) writes: >As I understand it GPS has a number of accurate (atomic) clocks which are >fundamental to determining ones position. One of the quoted applications >for GPS is for synchronising computer systems across the world using this >time information. > >How would such a system work and what advantages would this offer over >conventional handshaking techniques? GPS position-finding works by determining how far you are from several of the satellites, and then finding the intersection of the spheres defined by those distances. The distances, in turn, are found by measuring speed-of-light lag of the signals from the satellites. The satellites just basically broadcast extremely accurate time signals ("the time is now 12:45:23.6465346533") plus current orbital positions. Of course, what you can observe is not absolute lag, but relative lag -- how long the signal from one satellite took relative to another -- but with an extra satellite or two, and accurate knowledge of the orbits, you can solve for the satellites' idea of the time and for your position. Since this scheme demands very accurate clocks on the satellites, and getting a position involves figuring out what absolute time they think it is, a GPS receiver quite incidentally knows the time down to a fraction of a microsecond. (In the spiffy military models, a fraction of a nanosecond.) 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 receiver is a spiffy one). If your computer has a GPS receiver, and you tell it to start processing at 11:17:05.8368461 sharp, it will start processing in exact synchronization with any other similarly-equipped computer that got the same instructions. -- 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: Tue, 24 Nov 92 17:57:35 EST From: John Roberts Subject: GAS -From: aws@iti.org (Allen W. Sherzer) -Subject: Re: Shuttle replacement -Date: 24 Nov 92 21:31:30 GMT -In article vento@mars.lerc.nasa.gov (Dan Vento) writes: ->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. As of when? There have been plenty flown this year - in fact, I believe *Dennis* has flown at least one this year. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 24 Nov 92 16:00:44 GMT From: Dave Hopkins Subject: GPS handheld receivers Newsgroups: sci.space Is the market for GPS handheld receivers is really as big as we've been lead to believe? What use will long, lat and alt be to anyone unless it it is fully integrated into a navigation system? ------------------------------ Date: Tue, 24 Nov 1992 18:56:56 GMT From: "Michael K. Heney" Subject: GPS handheld receivers Newsgroups: sci.space In article dhopkins@gpsemi.lincoln.com (Dave Hopkins) writes: >Is the market for GPS handheld receivers is really as big as we've been >lead to believe? What use will long, lat and alt be to anyone unless it >it is fully integrated into a navigation system? I'm a contractor to the Environmental Protection Agency (EPA), and there are a number of applictions of hand-held GPS that we're kicking around here. There's a lot of inspection and sampling work done by EPA, and two immediate uses of lat/long come to mind: 1) for various programs, there are "regional stndards" set for some measured quantity. Gasoline volatility is one. Lat/Long can give a more accurate indication of what the applicable standard is t the site, which is then used for enforcement purposes. 2) Modelling based on measurements made in the field. Accurate position info can be fed into a geographic data base system along with sample data providing better information for the models. -- 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: 24 Nov 92 19:16:21 GMT From: Dave Jones Subject: GPS handheld receivers Newsgroups: sci.space Dave Hopkins (dhopkins@gpsemi.lincoln.com) wrote: > Is the market for GPS handheld receivers is really as big as we've been > lead to believe? What use will long, lat and alt be to anyone unless it > it is fully integrated into a navigation system? Integrated nav. systems have been around for plenty of time. GPS will just be another (more accurate) source of information. And the system doesn't have to be a gods-eye-view you-are-here display. How about "sound alarm if we drag our anchor for more than 100ft from our current position" - this is built into marine Loran systems already. -- ||------------------------------------------------------------------------ ||Dave Jones (dj@ekcolor.ssd.kodak.com)|Eastman Kodak Co. Rochester, NY | ------------------------------ Date: 24 Nov 92 16:41:30 GMT From: Thomas Clarke Subject: Pumpless Liquid Rocket? Newsgroups: sci.space In article <1eth9sINNmi@transfer.stratus.com> det@phlan.sw.stratus.com (David Toland) writes: > In article schlegel@cwis.unomaha.edu (Mark Schlegel) writes: > >henry@zoo.toronto.edu (Henry Spencer) writes: > > > >>The hydrostatic head in the plumbing, while useful -- it figures into the > >>design calculations for both pump-fed and pressure-fed rockets -- is not > >>enough to run a pressure-fed engine particularly well. Even low-performance > >>pressure-fed engines need 5-10 atmospheres of pressure. (One atmosphere is > >>a 10m column of water, and most fuels and oxidizers are substantially less > >>dense than water.) > > > I'm surprised no one has posted what occurred to me (and I replied to > the original author via email). The reaction chamber has a pressure > that's approximately equal to the thrust of the engine divided by the > area of the nozzle orifice (actually a bit higher due to turbulence > losses in the nozzle), so you have this chamber pressure working against > the hydrostatic pressure. I haven't set up a mathematical model of > this, but I find it hard to believe that a practical rocket motor > could be built with a high enough hydrostatic pressure to feed the > reaction chamber. I think it works. Say the rocket has a 100 meter hydrostatic pipe, so the chamber pressure is 10 atm (147 psi){excuse mixed units}. If the nozzle orifice is 100 square inches, then the thrust is 14,700 punds. {Actually I think thrust chamber area times pressure is a better approximation to thrust when allowance is made for the expansion nozzle, but that does not change the argument} So if the fuel+structure weights less than 14,700 pounds the rocket begins to accelerate. The acceleration increase the pressure, increases the thrust, and away we go. As one poster pointed out it would be wise to have a valve at the bottom of the pipe to regulate flow and thrust. An aluminum pipe capable of resisting 14.7K of thrust would have a minimum cross section of .2 square inches (depending on alloy etc.) Give it 1/2 square inch for safety and to allow larger thrust under acceleration. This is 2000 cubic inches of aluminum which weighs about 220 pounds - not a lot of overhead on a system with 14.7K pounds of thrust. {A long slender pipe would be subject to buckling failure, so something like the guys on a sailboat mast would have to be used, of course} The area of the motor is likely to be 1000 square inches (34 inches diameter) if the throat is 100. If the tank has this same diameter (seems natural and somewhat aerodynamic), then it must be 407 inches long, about 10 meters, to hold 14.7K pounds of fuel as dense as water. A bizarre looking craft but it should fly!! I may have to build a small one. Anyone know of safe (& cheap) hypergolic propellants? -- Thomas Clarke Institute for Simulation and Training, University of Central FL 12424 Research Parkway, Suite 300, Orlando, FL 32826 (407)658-5030, FAX: (407)658-5059, clarke@acme.ucf.edu ------------------------------ Date: 24 Nov 92 17:11:20 GMT From: Glenn Chapman Subject: Russian Photon capsule lands in Pacific & comes to Seattle Newsgroups: sci.space Radio Moscow on Nov. 22 announced the successful splashdown of the Europe-American 500 sample capsule, which was launched on Nov. 16th (see Nov. 16th posting for launch details). This was a 5 day special flight of the Photon space processing style sample return probe. In this case the capsule is filled with items to send "good will messages" in celebration the voyage of Columbus. The capsule with landed about 300 Km (190 mi) off the Washington state Pacific coast and was recovered by a Russian satellite tracking ship. The ship will be docking in the Seattle area today (Nov. 24) and apparently will be open for visitors. A Tacomo TV stationed showed news clips this morning of the Photon capsule being lifted out of the sea onto the ship. Photon is a spherical capsule which is derived from the first Vostok capsules, not the more modern Soyuz bell shaped return system. The capsule will be on display in Seattle. In other activity on board the Commonwealth of Independent States Mir space station cosmonauts Anatoli Solovyov and Sergei Avdeyev Anatoli Artsebarski and Sergei Krikalev (up for 120 days now) ejected a small satellite from the air lock on Nov. 23. Meanwhile the CIS has been holding discussions with the European Space Agency concerning cooperative space programs. According to a Radio Moscow report agreement has been reached which will see 3 ESA cosmonauts visit the Mir space station in the next few years. Also $50 million in contracts will go to Russian space companies. Glenn Chapman School Eng. Science Simon Fraser U. Burnaby, B.C., Canada ------------------------------ Date: 24 Nov 92 10:23:20 GMT From: Bill Higgins-- Beam Jockey Subject: Safe, cheap hypergolics (was Re: Pumpless Liquid Rocket?) Newsgroups: sci.space In article <1992Nov24.164130.21385@cs.ucf.edu>, clarke@acme.ucf.edu (Thomas Clarke) writes: [description of spaghetti-strand hydrostatic-pressurized rocket deleted] >A bizarre looking craft but it should fly!! > >I may have to build a small one. Anyone know of safe >(& cheap) hypergolic propellants? Yes. Vinegar and baking soda. O~~* /_) ' / / /_/ ' , , ' ,_ _ \|/ - ~ -~~~~~~~~~~~/_) / / / / / / (_) (_) / / / _\~~~~~~~~~~~zap! / \ (_) (_) / | \ | | Bill Higgins Fermi National Accelerator Laboratory \ / Bitnet: HIGGINS@FNAL.BITNET - - Internet: HIGGINS@FNAL.FNAL.GOV ~ SPAN/Hepnet: 43011::HIGGINS ------------------------------ Date: 24 Nov 92 19:21:31 GMT From: Sam Warden Subject: Scientific method Newsgroups: sci.space It's been my very strong impression that very little working science is done according to this formal theory of hypothesis verifying, but rather the opposite: theories are in fact constructed to match the known facts. But they have to stand internal scrutiny for empirical `fudging'. You try to derive the known facts from your fundamental assumptions in a way that is both rigorous and elegant, and what is tested by your (collective) success or failure is those assumtions themselves. It seems to me. ;-) -- samw@bucket.rain.com (Sam Warden) -- and not a mere Device. ------------------------------ Date: 24 Nov 92 22:04:47 GMT From: Henry Spencer Subject: shuttle payload limits Newsgroups: sci.space In article <23NOV199223205010@judy.uh.edu> wingo%cspara.decnet@Fedex.Msfc.Nasa.Gov writes: >>That "rated capacity" is obsolete; the shuttle has never been capable of >>lifting that much without violating one operating rule or another. (Yes, >>this means that the original specs were never met.) > >No this means that after the development was nearly complete NASA added abort >modes to the launch phase that put severe strains on the orbiter frame. This >LATE requirement caused NASA to derate the lift capability of the orbiter... Say I'm a customer. I don't care *why* it doesn't meet the specs. All I know is that it was supposed to be capable of (safely) launching my 65000lb payload, but in fact it has never been cleared to do so. I call that not meeting the specs. (Who am I? Hint: I wear a blue uniform, and I *wrote* that 65000lb requirement. It was a firm spec, not just a vague guideline.) >... It is my understanding that some space station >element flights will be as high as 44,000 to 47,000 lbs. They will of course >waive some of the constraints on the abort modes for these flights. >... There are no payloads heavier than SS Freedom elements. Not any more, because nobody's going to build something that they'd never be allowed to fly. If memory serves, those SSF elements have had radical surgery at least once to keep them within shuttle weight limits. There would be bigger payloads -- a few -- if the shuttle was allowed to go up with more. -- 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: 24 Nov 92 18:31:35 GMT From: Pat Subject: Shuttle replacement Newsgroups: sci.space In article <1992Nov24.062745.4287@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: > >Spacelab and Astro are two payloads that we want very much to return >from orbit on a regular basis. That allows them to be easily refitted >with new experiment racks and reflown. *That's* more cost effective >than throwing them away each time or refitting them in space. Neither >spam in a can nor a space station can handle the needs of those missions >as effectively or as cheaply as Shuttle. Not that they are all that >cheap mind you, but the experimental community thinks them worthwhile. > I think astro only returns because the shuttle returns. Most astro program objectives could be flown on expendable sattellites rather like IUE. i am certain IUE, COBE, IRAS have performed as ably as ASTRO without the launch delays or costs. Notice NASA is funding the 4 great observatories. if ASTRO was so great, they'd fly it more. Space lab is useful, certainly, but you could automate it and fly most of the experiments on disposables with return capacity if you really wanted. certainly the shuttle has certain unique capacities but judging how often LDEF, ASTRO and SPacelab have flown over the last 12 years, i dont think people are dying for those missiions. >wasteful. Might as well bring down a satellite or two at the marginal >cost of a little maneuvering fuel. It's only useful for LEO satellites >due to the lack of direct to GEO capability of the Shuttle, which is >a shame, but it is a viable approach for those cases where Shuttle >will be going to those orbital altitudes anyway. The problem is that > I think this is easier said then done. Henry, Alan???? >>Atlas is close. If it can't, we can go with Titan III for far far less. > >Splash. > > >> >>The new Titan SRMs will close most if not all of that gap. > >Boom, boom. > Easy slam. but an ad hominem attack doesnt make an argument. I believe henry pointed out awhile ago that the shuttle has no greater flight safety record then any expendable launcher. actually i think he pointed out that the man rated versions of launchers were not statiscally significantly improved over the non man rated versions. fact is you could describe the shuttle with the same Boom Boom. > >> >>In the last ten years or so almost all the boosters have been blown up >>by range safety. > >Small confort to a crewed vehicle. Boom is boom. > Nonsense. a booster destroyed by the RSO is part of a planned process. All previous manned missions had emergency escape provisions for the crew during boost. I cant remember wether apollo used a escape rocket or the SM engines, but the crew could get clear. certainly not fun, but probably no worse then ejection seats. certainly any manned vehicle would have this capacity. Henry, does the Soyuz have an escape rocket???? >>>the idea of a powered descent and vertical >>>landing gives me the willies... >> >>Much safer than airplanes for most people. A DC crash will only affect the >>Spaceport. When aircraft crash they tend to kill people on the ground. > >And a Shuttle crash landing is that of a glider, no boom, and perhaps >survivable by the crew. Plus who says the SSTO will crash on the Spaceport >grounds, few aircraft do. If they have a guidance failure, it might be >downtown Disney World. All those kids, consumed in flaming rocket fuel, >I can see the headlines now. > Actually, i think you are wrong there. i doubt a guidance failure would be any worse for a DC-Y,1 then for a 747. remember it is a piloted ppowered vehicle. if the ILS screws, the crew is still able to visualy guide as well as get instructions from ground control. now a control systems failure is possible, but with triple redundancy and smart pilots even many severe control failures can be flown around. i know of L-1011's flown in without elevator controls. United almost landed a DC-10 minus an engine and all controls. Convertibles have been landed. Besides, a DC flies on LOX/LH. coming in it should be low fuel and LOX/LH does not really explode effficiently. you get steam and water not a big boom. Several thousand pounds of JP-4 burns much better then LOX/LH i would bet. the LOX should disperse rapidly and the LH burns but not as persistently as a petroleum fire. ------------------------------ Date: 24 Nov 92 18:34:42 GMT From: Pat Subject: Shuttle replacement Newsgroups: sci.space In article <1992Nov24.151915.28177@iti.org> aws@iti.org (Allen W. Sherzer) writes: > >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. > Sounds like a Jaguar XJ-12E circa 1977 :-) ------------------------------ Date: 24 Nov 92 18:39:38 GMT From: Pat Subject: Shuttle replacement Newsgroups: sci.space In article amon@elegabalus.cs.qub.ac.uk writes: > >BTW... Did the pictures of the Isreali crash into an apartment block get shown >on the air over in the US (and the rest of the world) as much as here? Anyone >heard outcries to allow 747's to only take off and land over water? > YES, We get Cnn here:-) and usually we route aircraft over water, but they call it noise abatement. The pilots hate it BTW. ------------------------------ Date: Tue, 24 Nov 1992 19:38:20 GMT From: Dan Vento Subject: Shuttle replacement Newsgroups: sci.space In article <1992Nov24.151915.28177@iti.org>, aws@iti.org (Allen W. Sherzer) wrote: > > In article <1992Nov24.062745.4287@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: > > >Spacelab and Astro are two payloads that we want very much to return > >from orbit on a regular basis. > > No, Spacelab and Astor are two payloads that we want very much to keep > in orbit so they can be used. Building multi-billion $$ payloads and then > flying them for a few days every two years isn't cost effective. > No, you definitely want to be able to bring these kinds of payloads back on a regular basis at least until we have gained much more experience. Many, 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. Remember the Shuttle type small Space Experiments world (except for life sciences) has really only been around since the late 70's and we are only just learning to do many things that are taken for granted in ground-based laboratories. Being able to retrieve and refly payloads before building the space station version is the only way to prevent having a whole lot of space junk inside your $30 Billion dollar space station. Dan Vento vento@mars.lerc.nasa.gov ------------------------------ Date: Tue, 24 Nov 92 18:49:49 GMT From: Dave Jones Subject: Shuttle replacement Newsgroups: sci.space Gary Coffman (gary@ke4zv.uucp) wrote: > > Deadheading is never cost effective. But that's a management problem, > not a Shuttle problem per se. If you have to charge an entire Shuttle > mission against a satellite return, then it is expensive, but if the > return mission is piggybacked on a mission that carries things *to* > orbit, or does other experimental work, then landing *empty* is also > wasteful. Might as well bring down a satellite or two at the marginal > cost of a little maneuvering fuel. Folding two missions into one is not a trivial matter. Doing de-orbit with x tons of satellite aboard is a whole different ball game from doing it empty. You have to consider extra fuel to take up there for de-orbit, extra to maneuver from deployment orbit to pickup orbit, more supplies for extra time on orbit, more fuel to drive the extra supplies around, launch windows, and so on. Trying to retrieve an object can make the original payload objective impossible to achieve. NASA must love people who say "While you're up there, why don't you......". It ain't exactly climbing around on the roof of a house. -- ||------------------------------------------------------------------------ ||Dave Jones (dj@ekcolor.ssd.kodak.com)|Eastman Kodak Co. Rochester, NY | ------------------------------ Date: 24 Nov 92 21:31:30 GMT From: "Allen W. Sherzer" Subject: Shuttle replacement Newsgroups: sci.space 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. >No, you definitely want to be able to bring these kinds of payloads back on >a regular basis at least until we have gained much more experience. We want to bring back individual experiment racks. We don't want to bring back the entire lab. >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. >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. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------151 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: 24 Nov 92 16:08:20 EST From: Chris Jones Subject: Shuttle replacement Newsgroups: sci.space In article , prb@access (Pat) writes: >Nonsense. a booster destroyed by the RSO is part of a planned process. >All previous manned missions had emergency escape provisions for the >crew during boost. All US missions up through the fourth shuttle launch had crew escape provisions. After the loss of Challenger, the escape pole was added to the shuttle, so there were 21 missions flown with no escape provisions after launch, and I'd say that the shuttle currently has no escape provision during boost. > I cant remember wether apollo used a escape rocket >or the SM engines, It had an escape rocket. > but the crew could get clear. certainly not fun, >but probably no worse then ejection seats. certainly any manned vehicle >would have this capacity. Henry, does the Soyuz have an escape rocket???? Yes, all Soyuz flights have had an escape rocket. There have been two launch aborts of Soyuz flights: one just before liftoff in which the escape rocket pulled the spacecraft and its occupants to safety, and one during the third stage burn, which was again non-fatal, although a gruelling reentry featuring G forces around the 15 level. The two Soviet Voskhod flights (first multi-man crew and first EVA, respectively) had neither ejection seats (as flown on Vostok) or an escape rocket. -- Chris Jones clj@ksr.com ------------------------------ Date: Tue, 24 Nov 1992 21:27:05 GMT From: Henry Spencer Subject: Shuttle replacement Newsgroups: sci.space 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... > >No, you definitely want to be able to bring these kinds of payloads back on >a regular basis at least until we have gained much more experience... We want to bring back *individual items* from Spacelab, at varying times. But returning *small* payloads has never been a problem. The issue here is whether we want to be able to return *big* payloads in one piece. I see no major requirement to return a payload larger than one Spacelab experiment rack. Taking the infrastructure -- pressure hull, services, etc. -- up and down all the time is crazy. As is limiting the mission length to a week or two for the sake of hauling it up and down. -- 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: 24 Nov 92 18:22:27 GMT From: "R. S. Statsinger" Subject: Spaceborne Artificial Intelligence, Anyone? Newsgroups: comp.ai,sci.space Greetings! We've been funded this FY for a research project in spaceborne AI applications. This is an exciting topic, because we are just now entering the first generation of spaceborne computer technology with sufficient CPU bandwidth and address space to allow for reasonably sophisticated space software. Although much of the improved bandwidth and addressability in onboard computers is in support of improved sensors, the opportunity clearly exists to enhance the types of spaceborne software applications we deploy. Please note that this endeavor is every bit as exciting for commercial, non-military space applications as it is for the military. If we're ever going to explore the cosmos in galaxy-class warp-driven starships, then long before that we're going to need sophisticated, fault-tolerant, realtime, space-qualified software - and AI (along with generic operating systems for the coming generations of spaceborne computer architectures) is certain to be a part of this. Anyway, I've been wondering if this has ever been kicked around here in the Wonderful World of Usenet, and these two groups seemed like a good place to start. I'll try to follow these two groups for a while, but if anyone has anything to say on the subject PLEASE don't hesitate to send me email. Thanks much in advance. Bob Statsinger ------------------------------ End of Space Digest Volume 15 : Issue 454 ------------------------------