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 ; Wed, 13 Mar 91 01:42:28 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 13 Mar 91 01:42:22 -0500 (EST) Subject: SPACE Digest V13 #265 SPACE Digest Volume 13 : Issue 265 Today's Topics: Limits Toward 2001 - 11 Mar 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: Tue, 12 Mar 91 20:23:05 EST From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Limits >From: zephyr.ens.tek.com!tektronix!sequent!crg5!szabo@beaver.cs.washington.edu (Nick Szabo) >Subject: Re: Value per pound vs. cost per pound >>Nick: >>This "coasting phase to protect the ozone" is yet another constraint that >>must be imposed on a system already strained to its technical limits. >In article <1991Mar11.183441.687@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >>Nick's problem here is that he doesn't know much about launcher design, >>or he wouldn't make ridiculous statements like "already strained to its >>technical limits". >I certainly know a lot more than you've told us about. If you look >at the statistics of jet airplanes vs. rockets, for example fuel per pound >of payload, structural mass per pound of fuel, maximum speed, etc., you >will find that chemical rockets are stretched farther to the limits than >airplanes. If you mean that orbital rockets are more challenging to build and operate than commercial airplanes, and that higher velocities and greater amounts of energy are involved, then I agree with you. But "in the direction of the technical limits" in no way implies "already at the limits". Current digital electronics pushes toward the limits of its technology quite a bit further than the electronics of a few years ago, but there's no reason to assume that we can't get another order of magnitude or so more raw performance with existing approaches. >The cost of building jet airplanes has flattened out, and I >expect the cost of building chemical rockets has or soon will do likewise, >at similar per vehicle levels for freight ELV's, and much higher levels for >reusable passenger vehicles. >If you have any facts to refute this, please present them, but let's >not go around knocking people for lacking knowledge you yourself seem >to lack. I hope that is the extent of this little ad hominem volley :-( >>Launcher designers commonly trade off performance for >>reliability, ease of handling, use of existing hardware, etc.; you would >>not find such tradeoffs in systems that were stretched to their limits. >All transportation systems have these tradeoffs, including those that have >reached their economic limits. Performance, reliability, and ease of --------------- >handling are prerequisite characteristics for even being considered >"transportation". >>As a case in point, almost every launcher designer uses 3 or even 4 stages >>to get to orbit, when Atlas did it with 1.5 over thirty years ago. There >>are large margins of performance available if environmental constraints >>become serious enough to justify major redesign. >It doesn't seem that Atlas has significantly reduced launch costs. >Nick Szabo szabo@sequent.com >"What are the _facts_, and to how many decimal places?" -- RAH First, you assert that chemical rockets are at their *technical* limit, then when Henry contests this point, you give a batch of arguments that they're at their *economic limit*. I suppose you are entitled to your views on the economics (though I have serious misgivings as to their complete validity), but *technical limits* pertain to strengths of materials, atmospheric physics, square-cube laws, and so on, while economic limits relate only to whether a project (which may very well be technically feasible) is economically attractive or not. For instance, there's no technical reason that we couldn't mine gold from seawater, and in fact it has been done in the past, but with current techniques we'd be idiots to undertake it from an economic point of view. There are clearly established and proven methods of getting the gold much more cheaply. If you do not understand the distinction between technical and economic limits, then Henry's exasperation may be justified. If you do understand the distinction, then please do not twist the terminology like this. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 12 Mar 91 05:18:12 GMT From: agate!bionet!uwm.edu!wuarchive!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!pitt!nss!freed@ucbvax.Berkeley.EDU (Bev Freed) Subject: Toward 2001 - 11 Mar *********** TOWARD 2001 *********** Week of 11 March 1991 A Weekly Feature of SPACE CALENDAR + = Domestic (USA) Earth event * = Domestic (USA) space event o = International Earth event # = International space event -------------------------------------------------------------------- REPRINT INFORMATION This information is reproduced by permission of the Space Age Publishing Company. All rights reserved. Copyright March 11, 1991. Reproduction in any form without written permission violates federal statute with penalty of up to $50,000. SPACE CALENDAR is edited and published on the Big `Space' Island of Hawaii. ==================================================================== * * * * * * * + STS 37 Atlantis NASA KSC FL The mission to deploy NASA's second Great Observatory -- the Gamma Ray Observatory -- remains on schedule for early April. STS 39 Discovery, an unclassified DoD mission, is delayed until at least late April to repair cracks in its underside doors. * * * * * * * + Virginia Outstanding Industrialist Fairfax VA The accomplishments of Orbital Sciences Corp continue to bring honors to founder David W Thompson. In mid-February, Thompson was presented to both houses of the Virginia legislature and named the state's outstanding industrialist for 1991. * * * * * * * o Soviet Almaz Satellite Baikonur USSR Currently undergoing checkout with a late March or early April launch date. Space Commerce Corp, Houston TX, predicts data from the satellite -- 20m resolution in 6 shades of gray -- will be on the market by May 1991. * * * * * * * o Arianespace Asia Plans Tokyo, Japan Japan plans to buy 10 to 12 satellites during the next 8 years, said Arianespace chairman Charles Bigot. During a recent visit Bigot called on prospective users, including Nippon Telegraph & Telephone (NTT), Kokusai Denshin Denwa (KDD), and Japan Broadcasting Corp (NHK). * * * * * * * + General Dynamics San Diego CA Is replacing Space Systems Div head Alan Lovelace with Michael Wynne, whose space industry experience is almost nil. Speculation is rife that GD may leave the commercial space field, despite recent acquisition of the DoT's first launch operator's license. * * * * * * * o Aussat Brisbane, Australia The federal government is considering extending its protection of a telecommunications duopoly past 1997 in an effort to stimulate capital interest in Aussat. For the same reason, the Ministry of Transport and Communications could issue regional licenses for cellular mobile services instead of a third national license. * * * * * * * o Rocket System Corp Tokyo, Japan The 75-firm joint venture, which markets the H-2 rocket, plans to bid on 6 upcoming Intelsat and Inmarsat launch contracts by July. Lack of commercial space rules and regulations at Tanegashima Space Center could scuttle the company's near-term chances. * * * * * * * + Lunar Exploration Inc Houston TX Marketing manager Mark Lawson told Space News recently he has firm commitments from three American companies for a total of $4.5 million to sponsor the Lunar Prospector. Lawson expects ultimate project costs of about $11.5 million. * * * * * * * o Mexico Morelos Sat Earth Orbit Canada's Spar Communications Group will provide Mexico with a $3 million national air traffic control network using the Morelos satellite system. The network will eventually link 45 locations with voice and data transfer at 9.5 kilobits per second. * * * * * * * + Lunar Footnote (Statistic) 6,661 Days Since Moon last visited by humans. * * * * * * * o International Space Year 1992 (Quote) The most important policy objective of the ISY . . . is to instill a new Space Age frame of reference in the thoughts and actions of governments and individuals." -- The late U S Senator Spark M Matsunaga, Hawaii -------------------------------------------------------------------- ABOUT SPACE CALENDAR Space Calendar provides a weekly preview of upcoming events in the space industry. It is published weekly by the SPACE AGE PUBLISHING COMPANY from offices in Kailua-Kona Hawaii. For a free sample of the printed publication, use the address, telephone, or fax numbers for the Hawaii office listed below. SPACE AGE PUBLISHING COMPANY also publishes SPACE FAX DAILY from its offices in Cupertino California. For information about SPACE FAX DAILY use the address, telephone, or fax numbers for the California office listed below. HAWAII OFFICE: 75-5751 Kuakini Highway, Suite 209, Kailua-Kona HI 96740; 808-326-2014, fax 808-326-1825. CALIFORNIA OFFICE: 20431 Steven Creek Blvd, Cupertino CA 95054; 408-996-9210, fax 408-996-2125. ==================================================================== --- Opus-CBCS 1.14 * Origin: NSS BBS - Ad Astra! (412)366-5208 *HST* (1:129/104.0) -- Bev Freed - via FidoNet node 1:129/104 UUCP: ...!pitt!nss!freed INTERNET: freed@nss.FIDONET.ORG ------------------------------ End of SPACE Digest V13 #265 *******************