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 ; Thu, 4 Apr 91 02:06:01 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Thu, 4 Apr 91 02:05:56 -0500 (EST) Subject: SPACE Digest V13 #354 SPACE Digest Volume 13 : Issue 354 Today's Topics: Re: More cost/lb. follies Re: NY Times Article: Nuclear rocket SOLAR TERRESTRIAL BULLETIN - FLARE IMPACT EXPECTED nuclear rockets solid motor failure at edwards... Re: Fred on the Moon Air Force small launch contract Re: Government vs. Commercial R&D Re: More cost/lb. 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: 4 Apr 91 01:32:27 GMT From: swrinde!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!jhunix!ins_atge@ucsd.edu (Thomas G Edwards) Subject: Re: More cost/lb. follies In article <291.27F46C9E@nss.FIDONET.ORG> Paul.Blase@nss.FIDONET.ORG (Paul Blase) writes: >to: bpendlet@oscar.dsd.es.com (Bob Pendleton) > BP> Reusable, rugged, and low tech rockets should give a low cost > BP> per pound to orbit. From what I've read I'm convinced that > BP> this approach can work. >Check out my previous posting on the ALS. What, I think, Nick and others >are doing is confusing state-of-the-art performance with optimal price/lb >performance. The best rocket will not give the most economic performance >simply because getting the last 10% of performance out of a high-tech >engine will cost far more than the first 90%; putting 2 low-tech engines >on a booster is cheaper than putting a single high-tech engine with >equivelent thrust (allowing for weight differences). Whats more, we need to separate manned vs. unmanned launch technologies. We can dramatically lower cost to orbit by accepting 5%-10% launch failures (for relatively cheap satellites...the insurance question raises it's ugly head here though). No one would be thrilled with killing 5%-10% of all astronauts, so we spend the extra money and add redundancy to manned missions, but use cheap, low-tech, not even all that dependable boosters. Anyone remember SeaDragon? A large low-tech booster which would launch from sea after being inverted by a water-ballast section. It used decidedly non-delicate, low-tech parts so that re-usable stages could be recovered from high altitudes requiring a minimal amount of on-board recovery apperatus. -Tom ------------------------------ Date: 3 Apr 91 17:51:00 GMT From: agate!bionet!uwm.edu!spool.mu.edu!munnari.oz.au!metro!cluster!ray@ucbvax.Berkeley.EDU (Raymond Lister) Subject: Re: NY Times Article: Nuclear rocket > Article xxx of sci.space: > From: dlbres10@pc.usl.edu (Phil Fraering) > Subject: NY Times Article: Go out and get now! > Date: 3 Apr 91 16:43:42 GMT > > Run, don't walk, out to a newsstand and get a NY Times. It has an article > on a nuclear rocket supposedly being secretly developed by the DoD ... >Article xxx of clari.tw.space: [cross refed to several clari news groups] >From: clarinews@clarinet.com (ELIOT BRENNER) >Subject: Nuclear rocket being developed >Date: 3 Apr 91 15:31:24 GMT WASHINGTON (UPI) -- The Pentagon is trying to build a nuclear-powered rocket to boost huge payloads, satellites or weapons into space, scientists and government sources said Wednesday. Rather than using conventional chemical rocket fuels to generate a blast of hot gases to propel a rocket into space, the project involves vaporizing liquid hyrdogen into a far stronger exhaust stream by passing it over a bed of nuclear fuel pellets generating heat as high as 3,000 degrees. Internal government documents, obtained on the condition that their source not be divulged, show the program is still young and years away from completion. The documents also say the government already has studied safety hazards that might be associated with a sub-orbital test flight that could pass over the Antarctic and New Zealand. The existence of the program was revealed by the Federation of American Scientists, which objects to using nuclear reactors in flight operations close to Earth, preferring that the use of nuclear power be held solely to deep space missions. Work on the project is being monitored by the National Aeronautics and Space Administration, long interested in using reactor propulsion to drive interplanetary spacecraft. Nuclear power packs already are in use to produce electricity for spacecraft on long missions. Steven Aftergood, a senior FAS research analyst, said a nuclear- powered rocket could release radiation into the atmosphere, with some of the fissionable material being transferred into the exhaust gases as the liquid hydrogen is vaporized. He said test of a nuclear rocket engine during the 1960s, in a program known as Rover, produced radioactive releases. The current program is code-named Timberwind and is being conducted by the Strategic Defense Initiative operation within the Pentagon, the unit charged with developing defenses against ballistic missiles. It envisions space-based weapons along with sensing satellites to work in conjunction with ground-based missiles. The SDI office had no immediate comment on the matter. Aftergood said that studies have shown that a Titan 4 rocket equipped with a nuclear engine could put a payload of up to 70 tons into a low orbit while a conventionally powered Titan 4 could loft 20 tons. A reactor-powered rocket is believed capable of generating double the specific impulse, a measure of rocket power, of the main engines on the space shuttle. Specific impulse defines how long a pound of a fuel will produce a pound of thrust. The shuttle's engines, the most efficient in the world, produce a specific impulse of 455 seconds. A reactor rocket is believed capable of a specific impulse of more than 900 seconds. Aftergood said that a nuclear-powered rocket could lift off under its own power or use a conventional booster to get it up and away from Earth before kicking in the nuclear thrusting device. The proposed flight test envisions using a conventional booster to get up into the atmosphere before the nuclear aspect was activated. The Washington Post reported Wednesday that U.S. officials have told congressional leaders that reactors on either military or civilian rockets would not be started until they reached an altitude high enough to prevent any radioactivity generated during their use from re-entering the atmosphere. ------------------------------ Date: Wed, 3 Apr 91 12:29:44 MST From: oler%HG.ULeth.CA@BITNET.CC.CMU.EDU (CARY OLER) Subject: SOLAR TERRESTRIAL BULLETIN - FLARE IMPACT EXPECTED X-St-Vmsmail-To: st%"space+@andrew.cmu.edu" /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ SOLAR TERRESTRIAL BULLETIN 03 April, 1991 Flare Impact Assessement Update /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ UPDATED FLARE IMPACT ASSESSMENT The major class M6/2B flare of 02 April did manage to eject protons. Protons passed event thresholds of 10 pfu at greater than 10 MeV at 08:15 UT on 03 April. Protons reached a tentative peak of 25 pfu at 09:10 UT and have since declined to around 18 pfu as of 18:30 UT. We are currently expecting a terrestrial impact from this latest flare. With the proton event now in progress, models are indicating a moderate to high probability for a terrestrial impact. The geomagnetic field is expected to become more active on 04 April. Activity will most likely reach at least minor storm levels. Models are suggesting an estimated A-index value of about 35 to 40 for 04 April, falling to about 25 on 05 April. There is a chance activity could be higher than predicted. There is also a chance that no impact will occur at all. However, considering all aspects of this flare, a terrestrial impact is now expected. The geomagnetic storming (if it occurs) should begin somewhere near 18:00 UT on 04 April (give or take several hours). There was no Type II sweep observed with this event (which does not necessarily mean there wasn't a Type II which occurred), so we are leaning slightly towards a gradual storm commencement rather than an SSC type magnetic signature. But either is possible. Auroral activity over high latitudes will reach high levels if this disturbance materializes. Some periods of major magnetic storming are possible over middle and high latitudes (particularly high latitudes). Middle latitudes will likely witness mostly moderate auroral activity with a risk for brief periods of high auroral activity. Since lunar phase will not interfere with attempts to view auroral activity, some southerly middle latitude areas may be able to witness low levels of auroral activity far to the north or northeast. It will be difficult, however, to spot auroral activity with the naked-eye that far south. HF propagation conditions should become somewhat degraded on 04 April if a terrestrial impact materializes as expected. Conditions are already degraded more than usual due to the enhanced geomagnetic and auroral activity which has been observed lately. A further decrease in the quality of propagation is expected on 04 April over most latitudes. However, no blackout conditions are expected for the middle and low latitudes. This storm event (if it occurs) will not be nearly as powerful as the last major geomagnetic storm event which occurred in March. VHF propagation conditions will remain mostly normal to below normal on 04 April. Middle and high latitudes may experience periods of auroral backscatter communications, particularly in the late afternoon and near local midnight. The extent of the auroral communications will depend on the magnitude of the geomagnetic activity. If activity reaches levels currently expected (A-index of 35), no significant widespread auroral backscatter will likely be observed. However, local sporadic auroral backscatter will be possible over the middle latitudes if magnetic activity reaches these levels. More common auroral propagation will occur over the northerly middle and high latitudes. A POTENTIAL GEOMAGNETIC STORM WARNING has been issued for 04 April. This recent flare combined with the coronal-induced magnetic activity should push the geomagnetic field into low to moderate intensity minor storming. Conditions should improve somewhat on 05 April, although a return to more quiet levels is not expected for several days. PLEASE SEND ANY REPORTS OF AURORAL ACTIVITY, AURORAL BACKSCATTER COMMUNICATIONS, HF DEGRADATION OR OTHER ANOMALIES TO: OLER@HG.ULETH.CA. PLEASE INCLUDE THE TIME (UT AND LOCAL), LOCATION OF OBSERVATION AND A SHORT DESCRIPTION OF THE PHENOMENA OBSERVED. THANKS TO ALL THOSE WHO TAKE THE TIME TO SEND IN REPORTS. The following alerts are IN PROGRESS: - SATELLITE PROTON EVENT ALERT (CURRENT LEVEL: 16 PFU @ > 10 MEV @ 1830 UT) - PROTON FLARE ALERT (02 APRIL) The following warnings are IN PROGRESS: - POTENTIAL GEOMAGNETIC STORM WARNING (FOR 04 APRIL) - POTENTIAL POLAR CAP ABSORPTION EVENT WARNING (40% PROBABILITY) - POTENTIAL POLAR TO HIGH LATITUDE HF SIGNAL BLACKOUT WARNING (30% PROB) - POTENTIAL MAJOR SOLAR FLARE WARNING ** End of Bulletin ** ------------------------------ Date: 3 Apr 91 21:45:17 GMT From: emperor!daver@uunet.uu.net (Dave Rickel) Subject: nuclear rockets I saw an article in the local paper today about a nuclear booster the DoD was supposed to be developing for SDI. From what i could gather, the working fluid was hydrogen, the Isp was on the order of 900 secs, and they were talking about testing in the atmosphere. That would tend to imply a large thrust. Ahh. The paper said the project was code-named Timberwind, was secret, and that the source was talking on conditions of anonymity. I assume there isn't any other information available, like how far along they are, what the weight and thrust and rough size of the thing are, what type of reactor is being used, etc. I'm kind of curious about how this compares to some older nuclear rocket programs--has any progress at all been made in the last 25 years? Someone last year was going to submit a summary of the Dumbo nuclear rocket proposal (a contemporary of NERVA, that lost out because it was too ambitious). Our news feed was flakey at the time; if the summary did get posted, could someone email me a copy? Thanks. david rickel uunet!emperor!daver ------------------------------ Date: 2 Apr 91 23:26:07 GMT From: sco!gorn!everyman@uunet.uu.net (arvey j. shier) Subject: solid motor failure at edwards... does anyone out there know what happened at edwards afb with regard to a solid motor test for titan 4...it was my understanding that the titan 4 was already an operational booster vehicle which utilized 7 segment solid rocket motors as compared to the 5 segment motors in the titan 3 booster....it is possible that an advanced version of the 7 segment motor is in development...i am a retired aerospace engineer who worked with the solid rocket motor development early on...i have lost touch and would like to know what happened at edwards the other day...i can recall with sharp memory a failure experienced at edwards in the mid-sixties during the development of the titan 3 booster vehicle... ------------------------------ Date: 3 Apr 91 18:30:03 GMT From: prism!dsm@gatech.edu (Daniel McGurl) Subject: Re: Fred on the Moon In article 18084TM@MSU.EDU (Tom McWilliams) writes: >Re; Fred on the Moon. [lot's of reasons to place Fred on the moon] I can only see two major problems with this: 1) Where do you do the 0g crystal growing? 2) Do you gain anyhitng because you have to have extra fuel and packaging to land on the moon, and then get materials back. -- Danny McGurl "How straightforward the game Office of Information Technology and when all its rules are respected." Information and Computer Science Major at: Georgia Institute of Technology ARPA: dsm@prism.gatech.edu ------------------------------ Date: 3 Apr 91 22:31:00 GMT From: o.gp.cs.cmu.edu!netnews@PT.CS.CMU.EDU (Vincent Cate) Subject: Air Force small launch contract I have been told (by somebody who stands a good chance of knowing) that Orbital Sciences Corp is the only company with a bid in on the Air Force contract for 5 small launches per year. Does anybody know if this is true? Does anybody know of any other company bidding on this contract? Assuming this is true, does anyone know why? It seems there are a number of companies bidding on the Motorola replacement launches and I would think these same companies would be interested in the Air Force contract too. Thanks for any info, -- Vince ------------------------------ Date: 3 Apr 91 00:46:04 GMT From: mips!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!wa4mei!ke4zv!gary@apple.com (Gary Coffman) Subject: Re: Government vs. Commercial R&D In article <21445@crg5.UUCP> szabo@crg5.UUCP (Nick Szabo) writes: > >A review of the statistics: of U.S. patents granted in 1989, 79,088 (76%) >were issued to corporations, 23,624 (23%) to private individuals, and >700 (1%) to governments. Some of the corporate and individual patents >are aided directly or indirectly by government money, of course. But >the bottom line is that direct DoD, NASA, DOE, etc. work accounts for >only a very small fraction of our technological advances. All this proves is that government research is rarely patented. Much of it is released into the public domain (it was after all publicly funded), and much of it is classified (military applications). So the patent statistics are not a reasonable measure of the productivity of government research. This doesn't mean that government research is good or productive. It merely means that these statistics don't prove that it is not. Gary ------------------------------ Date: 3 Apr 91 18:18:24 GMT From: swrinde!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: More cost/lb. follies In article <1991Apr2.174002.1913@linus.mitre.org> sokay@cyclone.mitre.org (S. J. Okay) writes: >Namely, how much are parts like this interchangeable? Is your standard >Delta or Titan a made-to-order unique vehicle, or are there certain things >that are more or less off-the-shelf parts. Engines are often *almost* off-the-shelf parts, because they have some tendency to outlast specific booster configurations. Delta's main engine is a slight variant of the Atlas "booster" engine, which in turn is a derivative of the Navaho booster engine. (Navaho was the last of the USAF's enormous intercontinental cruise missiles in the 50s, and was cancelled before first flight.) Other variants of the same engine were the first-stage engines for the Saturn I and Saturn IB. On the other hand, there is usually some small degree of customization; Delta engines are not interchangeable with Atlas engines, although major subassemblies should still be. That's sort of the overall pattern, in fact. Various subsystems often are slightly-customized variations on standard parts. >...get an engine assembly from Engines 'R' Us, mate it to an third-party >fuel tank and then wrap your own external skin around it? (Minor quibble: there is no separate external skin. The tank wall has fuel on one side and air on the other, although hydrogen tanks in particular may have a layer of insulation either inside or outside.) It's not quite that easy. Things like the tankage and structure tend to be fully custom-built, there is a lot of minor customization even of the standard subassemblies, and considerable effort is needed to make everything work together smoothly. There isn't enough of a mass market for varying configurations to justify plug-together launchers. >I realize avionics are pretty specific and probably wouldn't apply here... Actually, avionics can be pretty generic, since a computer is a computer (although it may have slightly different software). Details like the electrical interface to the propulsion hardware can vary a lot, though. -- "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 ------------------------------ End of SPACE Digest V13 #354 *******************