Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Sun, 31 Mar 91 02:13:51 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sun, 31 Mar 91 02:13:44 -0500 (EST) Subject: SPACE Digest V13 #333 SPACE Digest Volume 13 : Issue 333 Today's Topics: Advancing Launch Technology Re: Linear launchers on Earth Re: economic vs technical limits Re: EM Launchers and G loads Re: Commercial Space news (5 of 12) Yup, it was an aurora. Update: Free Cray Time for SISAL Users Re: "Follies" Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 29 Mar 91 01:03:43 GMT From: zephyr.ens.tek.com!tektronix!sequent!crg5!szabo@beaver.cs.washington.edu (Nick Szabo) Subject: Advancing Launch Technology In article <1C3FF2E5EC000082@BITNET.CC.CMU.EDU> 18084TM@MSU.BITNET (Tom McWilliams) writes: >So, Nick, since chemical rockets are too costly and stretched to their limits, >in terms of cost/kg and technical capability, what do you propose as a fuel >for getting anything, people or frieght, to LEO? Good question. I'll work with GEO and L-5 (roughly equivalent in cost) instead of LEO, since we are talking about space industry and colonization, and different technologies differ in their ability to get to various orbits. Note again that I am talking about reductions more than a factor of 5 below today's costs (from $20,000/lb. to $4,000/lb. from earth surface to GEO or L-5) that should be the focus of government research. Near-term incremental advances and changes in scale for chemical launchers can best be accomplished by private enterprise. I'll review some of the possibilities here: Freight: Gas gun ("hyperaccellerator": horizontal or ocean-based vertical) Electromagnetic Launch (EML): railgun, coilgun, or mass driver space-manufactured tether & counterweight, combined with: gas gun EML laser launch balloon Passengers: laser launch space-manufactured tether & counterweight, combined with: laser launch airplane balloon There are also many other technologies and combinations of technologies that could end up providing the lowest cost. I don't know if it's published, but Dani Eder and Space Research Associates in Seattle have written a paper, "50 Ways to Leave Your Planet", that outlines much of what has been studied. As in any R&D, some of these technologies _won't_ pan out, but they all look promising, and need much greater attention devoted to them. What many of these technologies have in common is that the energy source is not stored on board. This gets us away from the hideous fuel/structure and fuel/payload ratios of chemical rockets. Another strategy is using mass and energy from space, which is potentially much cheaper than using mass and energy from earth. Once space manufacturing technology is mature, earth mass and energy need only get us above most of the atmosphere, a suborbital regime that takes less than one-third the energy of going to orbit. This regime might even be accomplished by high-altitude airplanes and balloons. Not only do these technologies represent the best long-term solution, but many of them (esp. gas gun and EML) could reduce costs for freight dramatically over the next 10 years, for bootstrapping space industry. All three types of EML listed (coil gun, railgun, and mass driver) and at least one kind of gas gun have working prototypes. Sandia says it can develop a $500/lb. to GEO coil gun for $2 billion (less than the cost of one Space Shuttle). This compares to $20,000/lb. to GEO for chemical rockets: a reduction by a factor of 40 in five years. How about let's give Sandia a chance to show its stuff? Over the long term, EML or gas gun could drop costs to $10/lb. to GEO or L-5. With warm superconductors, the cost could drop much further, my guess being $1/lb. Lower space freight costs will, via space industries, feed back into reduced passenger costs over the long run, in the form of tethers and other upper stages manufactured in space. None of these technologies have received significant funding, because chemical rocket research has unfairly (and to our great detriment) dominated space launch R&D. NASA in particular needs a more balanced program that concentrates on those technologies that have the greatest possibilities of advance. -- Nick Szabo szabo@sequent.com "If you want oil, drill lots of wells" -- J. Paul Getty The above opinions are my own and not related to those of any organization I may be affiliated with. ------------------------------ Date: 28 Mar 91 20:45:22 GMT From: agate!bionet!uwm.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@ucbvax.Berkeley.EDU (Henry Spencer) Subject: Re: Linear launchers on Earth In article <9103280312.AA12524@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) writes: >Now, when you fire your launcher, the projectile shoots out of the muzzle, >and -BLAMMO!- ricochets off the slope of the steel mountain, flying off >into space at a nice, steep, atmosphere-avoiding trajectory. Uh, nope. What happens is that you get a small fireball on the side of your steel mountain, the end result being a small crater in it. Things don't ricochet at that kind of velocity. Think meteorite, not baseball. >... I believe the shock wave of the projectile passing through the >atmosphere would generally be great enough to kill everything for several >miles around (and it could be heard for hundreds of miles)... Depends on the size of the payload; the lethal-radius numbers I've heard have been rather smaller. But yes, 8km/s near sea level is noisy. :-) -- "The stories one hears about putting up | Henry Spencer @ U of Toronto Zoology SunOS 4.1.1 are all true." -D. Harrison| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 28 Mar 91 17:36:16 GMT From: zephyr.ens.tek.com!tektronix!sequent!crg5!szabo@beaver.cs.washington.edu (Nick Szabo) Subject: Re: economic vs technical limits In article <281.27EF2690@nss.FIDONET.ORG> Paul.Blase@nss.FIDONET.ORG (Paul Blase) writes: [Technical advances on many fronts] This is a perfect example of why technical and economic arguments are inseparable when talking about costs. With all this technology listed, we are still left with no idea about its impact on costs. 5%? 50%? Maybe it will _raise_ costs because the new materials are more expensive? (This was part of the problem with Shuttle costs). The general economic/technical idea you were getting at is that rocket costs will tend to drop at about the same rate as other chemical forms of transportation, such as airplanes, because they involve similar technologies and are impacted by many of the same advances. That's pretty much what I've been arguing. When I can pay $.10 (ten cents) for round-trip from PDX to Heathrow, I'll start getting ready for space colonization via chemical rockets. -- Nick Szabo szabo@sequent.com "If you want oil, drill lots of wells" -- J. Paul Getty The above opinions are my own and not related to those of any organization I may be affiliated with. ------------------------------ Date: 29 Mar 91 20:05:11 GMT From: zephyr.ens.tek.com!tektronix!sequent!crg5!szabo@beaver.cs.washington.edu (Nick Szabo) Subject: Re: EM Launchers and G loads In article RANCK@VTVM1.CC.VT.EDU ("Wm. L. Ranck") writes: > Now, my question is this. Why does everyone assume that you want >maximum acceleration from the system in the shortest possible distance. >I can see that it make the system cheaper to build and the energy >efficiency is probably better; but why not build a long rail system >that accelerates the payload at 2 or 3G over many miles. The problem pretty much boils down to economics. (Repeat after me: "economics and technology are inseparable" :-). The cost of the extra superconducting magnets and the civil engineering over tens of kilometers would really add up, probably to $tens of billions. Unless there is demand for launch of $tens of billions of payload with a specific mass and into the specific orbits best reached by the gun, it does not make sense to spend so much money on a single configuration. Right now, the annual commercial demand for _all_ orbits and payload sizes is closer to $1 billion. Over the long term, if low-cost, mass-produced warm superconductors become feasible, and demand rises sharply, it might be possible to build very large, low-G EMLs suitable for launching passengers. Well before then, we will have perfected the technology with smaller freight EML's costing $100's of millions instead of $tens of billions. That said, I strongly agree that there are many important variables for guns besides length/muzzle velocity. Like cost/lb., it is only a rule of thumb and should not be focused on to the exclusion of other variables. Other important variables for guns are payload and gun stresses (not just G's in one direction), cost of materials (current superconducting and high-power equipment is expensive), mass (if we want to mount the gun on an airplane or under balloons), and I am sure I have missed quite a few other important ones. -- Nick Szabo szabo@sequent.com "If you want oil, drill lots of wells" -- J. Paul Getty The above opinions are my own and not related to those of any organization I may be affiliated with. ------------------------------ Date: 29 Mar 91 18:14:10 GMT From: idacrd!mac@princeton.edu (Robert McGwier) Subject: Re: Commercial Space news (5 of 12) From article <2835.27EF719C@ofa123.fidonet.org>, by Wales.Larrison@ofa123.fidonet.org (Wales Larrison): > (cont) > tiveness of European and Japanese firms. However, the NASA > participation with the AMSC has recently drawn fire from Inmarsat > (which offers a different type of mobile communications service), > and from some European governments as being government support for a > commercial industry.] > And if you will pardon me, WHAT THE HELL does Europe think ESA/Arianespace Matra, Daimler-Benz (which now owns MBB), and all the other semi-private `corporations' in Europe are but government subsidized and/or out right ownership of companies in competition of ours. The government and treaty granted monopolies to INMARSAT, COMSAT, others in many areas makes me want to puke and I can only say IT IS ABOUT TIME THE GD US Government did SOMETHING to aid OUR companies who are trying to compete with other companies in an international market where these companies are either owned by the government or controlled or heavily subsidized by them. The US is becoming a third world country, exporting more scrap and raw materials and less high tech (high value, high value added manufactured goods) each and every day. I can't understand how or why the US government will not make SOME move to encourage there industries. Bob -- ____________________________________________________________________________ My opinions are my own no matter | Robert W. McGwier, N4HY who I work for! ;-) | CCR, AMSAT, etc. ---------------------------------------------------------------------------- ------------------------------ Date: 26 Mar 91 16:41:54 GMT From: amdcad!dgcad!dg-rtp!groupw!rice@ucbvax.Berkeley.EDU (Brian Rice) Subject: Yup, it was an aurora. From the Raleigh, N.C., News and Observer, March 26, 1991, p. 4B: "North Carolina residents got a rare chance to see the Northern lights and many of them called police to ask if they knew the source of the red glow in the sky [and whether it could be arrested and brought to justice :-) ]. "The lights appeared between about 8:30 p.m. and 11 p.m. Sunday and were seen across most of the state." So that's it. Ya know, I probably should have made the connection with the fact that the aurora looked like a monster version of the result of a CRAF release, which was described as an "artificial aurora." But I had these preconceived notions that auroras had a curtain-like appearance and that they "shimmered," while what was seen here (at least at the times I observed it) was simply a large spherical glow, fairly static in appearance except for changes in size and brightness. Obviously, those notions of mine are not always true. Another lesson of this is "Don't believe everything the fuzz tells you about atmospheric science" (well, I guess this should be sort of obvious, as nobody asks Willard Scott about law enforcement matters :-). I'd love to know how that spurious NWS report came into existence. Thanks to Rory McLeod (who observed the aurora from Charlottesville, Virginia), Phil Fraering, David Palmer, and Paul Dietz for sending mail. -- Brian Rice rice@dg-rtp.dg.com +1 919 248-6328 DG/UX Product Assurance Engineering Data General Corp., Research Triangle Park, N.C. "Boy, I hope those dogs eat that cat." --Tula, age 3 ------------------------------ Date: 28 Mar 91 19:37:08 GMT From: amdcad!military@ucbvax.Berkeley.EDU Subject: Update: Free Cray Time for SISAL Users From: usenet@lll-winken.llnl.gov This is an update of an earlier posting which contained errors. We apologize to the net commmunity for wasting bandwidth; we think we've got it right this time... ---------------------------------------------------------------------------- The Sisal Scientific Computing Initiative Contacts: John Feo and Dave Cann The Computing Research Group at Lawrence Livermore National Laboratory (LLNL) announces the Sisal Scientific Computing Initiative (SSCI). The Initiative will award free Cray X-MP time and support to researchers willing to develop their applications in SISAL, a functional language for parallel numerical computation. Members of the Computing Research Group will provide free educational material, training, consulting, and user services. SSCI is an outgrowth of the Sisal Language Project, a collaborative effort by Lawrence Livermore National Laboratory and Colorado State University and funded in part by the Office of Energy Research (Department of Energy), U.S. Army Research Office, and LLNL. SISAL provides a clean and natural medium for expressing machine independent, determinate, parallel programs. The cost of writing, debugging, and maintaining parallel applications in SISAL is equivalent to the cost of writing, debugging, and maintaining sequential applications in Fortran. Moreover, the same SISAL program will run, without change, on any parallel machine supporting SISAL software. Recent SISAL compiler developments for the Alliant FX/80, Cray X-MP, and other shared memory machines have resulted in SISAL applications that run faster than Fortran equivalents compiled using automatic concurrentizing and vectorizing tools. Interested participants should submit a 1-2 page proposal by June 1, 1991 to Computing Research Group, L-306 Lawrence Livermore National Laboratory P.O. Box 808 Livermore, CA 94450 Proposals should describe the research and explain how the work will benefit from parallel execution on a Cray X-MP. We will announce accepted proposals by July 1, 1991. For more information about the Sisal Scientific Computing Initiative please contact John Feo (feo@lll-crg.llnl.gov) at (415) 422-6389 or Dave Cann (cann@lll-crg.llnl.gov) at (415) 423-7875. We look forward to hearing from you. ------------------------------ Date: 26 Mar 91 19:58:18 GMT From: agate!stanford.edu!snorkelwacker.mit.edu!think.com!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!pitt!nss!Paul.Blase@ucbvax.Berkeley.EDU (Paul Blase) Subject: Re: "Follies" to: roberts@CMR.NCSL.NIST.GOV (John Roberts) (re ongoing conversation with Nick Szabo on the economic viability of rocket launchers). JR> There *is* JR> increased interest now in reducing per-pound chemical rocket JR> launch costs - for instance the expanded Delta and Titan JR> designs described by Allen Sherzer (with hope for up to 2-3X JR> drop in cost/pound, and availability in perhaps only a few JR> years), and ALS or the new technology launcher system (with JR> development expect a decade, and perhaps as much as 10X JR> reduction in launch going to extrapolate costs from the past, JR> and yet allow that will permit the current curve for exotic JR> launchers (flat a change, you must also allow that future JR> trends may allow th chemical rocket launchers to change too. Nice reply to Nick, thank you. I don't think that we have really started to push the technology of conventional launchers yet, and new technology is always coming along. There are three things, that I can think of off hand, that contribute to a launcher's cost: fuel, craft weight, and manufacturing cost. - I read in AW&ST where the Japanese are working on an air-breathing rocket design, where air is scooped in and liquified in flight. Oxidizer only must be carried for the exoatmosphere portion of the flight. Not having to carry LOX would not only reduce the fuel costs, it would make the whole craft lighter and cheaper to build. - With the NASP project, there is a great deal of research going on in the use of composite materials for things like cryogenic fuel tanks. Using these materials will make launcher bodies lighter and stronger. New materials, in particular ceramics, may also make the engines cheaper. - One reason that individual rockets cost so much is that the market is limited. In general, if the launch rate would go up, the per-unit cost would go down. Especially if we could agree on a limited family of launchers that could be combined to launch any desired payload - rather like the Soviets recycle all of their designs, strapping things together to reach the desired capability. --- via Silver Xpress V2.26 [NR] -- Paul Blase - via FidoNet node 1:129/104 UUCP: ...!pitt!nss!Paul.Blase INTERNET: Paul.Blase@nss.FIDONET.ORG ------------------------------ End of SPACE Digest V13 #333 *******************