Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Received: from andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests) ID ; Thu, 25 Aug 88 12:11:05 -0400 (EDT) Received: from andrew.cmu.edu via qmail ID ; Thu, 25 Aug 88 12:09:06 -0400 (EDT) Received: by andrew.cmu.edu (5.54/3.15) id ; Thu, 25 Aug 88 10:27:02 EDT Received: by angband.s1.gov id AA04261; Thu, 25 Aug 88 01:05:23 PDT id AA04261; Thu, 25 Aug 88 01:05:23 PDT Date: Thu, 25 Aug 88 01:05:23 PDT From: Ted Anderson Message-Id: <8808250805.AA04261@angband.s1.gov> To: Space@angband.s1.gov Reply-To: Space@angband.s1.gov Subject: SPACE Digest V8 #337 SPACE Digest Volume 8 : Issue 337 Today's Topics: Re: SETI (& STI) Re: Ozone layers Re: HOTOL funding cancelled Re: Aerospike 'prestigious' space programs Feedback Space Bloopers Re: SDI, Asats, and access to orbit Not in the line of duty Re: SETI: Why don't we hear anything? Re: space news from Juen 27 AW&ST ---------------------------------------------------------------------- Date: 15 Aug 88 17:44:20 GMT From: spacely!eto@elroy.jpl.nasa.gov (Edward Olsen) Subject: Re: SETI (& STI) The NASA SETI program will only be a SEARCH. It will be listen only. No Transmissions are not part of the program. The search space presently envisioned is (1) High Sensitivity Target Search of the nearly 800 solar type stars within 25 pc and (2) Low Sensitivity, Broad Band All Sky Survey. The Target Search will be carried out with a frequency resolution of about 1 Hz between 1 GHz and 3 GHz. Integration times will be 100 -> 1000 seconds using Arecibo and other large antennae (i.e. 70m DSN net, OSU, etc). Instantaneous bandpass will be 10 MHz to 40 MHz and polarization dual circular. Sensitivity achieved will be approximately 10**-26 watts/m**2. The Sky Survey will be carried out with a frequency resolution of 10 Hz to 30 Hz between 1 GHz and 10 GHz (and higher frequency spot bands). Integration times will be 1/3 -> 3 seconds using the DSN 34m net and possibly the NRAO 300 ft. Instantaneous bandpass will be 300 MHz and polarization dual circular. Sensitivity achieved will be approximately 10**-23 watts/m**2. The big problem is radio frequency interference --- keeping our signal detectorsfrom saturating with reports of all the local intelligent signals. Edward Olsen /******************************************************************* * Edward Olsen ARPA: eto@spacely.jpl.nasa.gov * * Mail Stop: 169-506 UUCP: ...!cit-vax!spacely!eto * * Jet Propulsion Laboratory SPAN: jplrag::olsen * * 4800 Oak Grove Drive * * Pasadena, CA 91109 * * * * Phone: FTS: 792-7604 Commercial: (818) 354-7604 * *******************************************************************/ ------------------------------ Date: Mon, 15 Aug 88 18:50:57 PDT From: Eugene Miya Subject: Re: Ozone layers 18:45 PDT start out bound. Peter Scott asks about Ozone, unfortunately, Bob Watson, one of the best men to ask this question isn't at JPL anymore, but there's lots of other people you can ask. Basically, inversion layers don't completely have much to do with it. 1st: we don't really understand the production (your word was regeneration) mechanism. Anything anyone tells you is a theory. 2nd: we don't completely understand the transport mechanism. It was only recently discovered that CFCs could convect so quickly, because the O3 doesn't (don't forget it's heavy). So generation is largely "in place." The "in place mechanisms are largely molecular and atomic oxygen up high combining. Some argued lightning was a production mechanism, largely too low in altitude, largely discounted. One person asked about working on scrubbers for CFCs up high, the problem here is the sheer size of the upper atmosphere. Prevention is a better treatment, but who knows, we may have passed points of no-return, maybe not. --eugene 18:54 PDT ------------------------------ Date: 15 Aug 88 19:58:41 GMT From: concertina!fiddler@sun.com (Steve Hix) Subject: Re: HOTOL funding cancelled In article <6233@ihlpl.ATT.COM>, knudsen@ihlpl.ATT.COM (Knudsen) writes: > > If I remember right, we were very interested a few years ago in > the British HOTOL (Reagan's "space plane", not heard of lately) Two different aircraft (air?). Similar missions, though. > and approached the British Govt about sharing the development. > We were rebuffed, the Brits saying tht the technology was too > advanced to share with anyone (secret, proprietary, ya know). Apparently Rolls Royce had solved some problems bugging US engine designers up to that point. Maybe it'll get out now. ------------------------------ Date: 15 Aug 88 14:14:49 GMT From: att!whuts!sw@ucbvax.berkeley.edu (WARMINK) Subject: Re: Aerospike In article , josh@klaatu.rutgers.edu (J Storrs Hall) writes: > What is an aerospike? What is meant by its being (or not being) > "plugged"? An aerospike is a sharp extension of a (usually) blunt nose cone. The idea is that by starting the shockwave ahead of the main nose cone, as far as the airflow is concerned, the nose cone has the same shape as the shockwave rather than its real, blunt, shape. This will reduce the supersonic drag quite considerably. I believe this is used on some of the submarine lauched ICBMs, like Trident, which are rather blunt-nosed so as to pack as much volume as possible into the limited space available. I'm not sure what 'plugged' refers to, I would hazard a guess at 'stored (i.e. retracted) position' or maybe it is a reference to the small cone at the end of the spike (the angle at the vertex (?) of the cone is the same as the angle of the shockwave at the velocity for which the spike is optimized). > > What is the specific impulse of hydrazine? Already been answered by another mailing. -- ------------------------------------------------------------------------------ If all the statisticians were laid end to | Stuart Warmink, APT UK Ltd. end across the Atlantic, 99% would drown :-) | !whuts!sw Whippany NJ USA -----------> My opinions are not necessarily those of APT UK Ltd. <----------- ------------------------------ Date: 16 Aug 88 01:04:03 GMT From: spdcc!eli@husc6.harvard.edu (Steve Elias) Subject: 'prestigious' space programs In article <907@altger.UUCP> Macros@altger.UUCP (Macros) writes: >In another article, ?? writes: >>program, the ESA's space program, Japan, China, India, Brazil, and >Controlling these countries might not even be too bad an idea. They should do >more in fighting poverty, starvation and their population >explosion, than diving into some prstigious space programs. why does this argument apply to other countries if it does not apply to the US & Soviets ? (leaving followups here, for lack of a better 'space' for them). ------------------------------ Date: 15 Aug 88 12:48:11 GMT From: nyser!cmx!anand@itsgw.rpi.edu (Rangachari Anand) Subject: Feedback Did anyone on the net catch an interesting call-in talk show on Public radio called "Feedback" last night? Last night's program was devoted entirely to space. There were several people on hand from NASA and from the Commerce department to answer questions about the US space program. Many of the callers appeared to be quite enthusiastic about the space program in general but more than one caller seemed to be very worried about the increasing role of the military in the space program. In response to this, the person from NASA said that the space station was to be devoted entirely to civilian activities.[This seemed to contradict reports published in Aviation week]. The other popular question was on whether the spinoffs from the space program justified the investment. NASA has apparently calculated that $8 is returned for every $ spent. I myself was able to get in a question on the topic of expendable launch vehicles. I tried to point out the virtues of a simple and cheap launcher. As an example, I mentioned that the reliable Proton rocket was essentialy unchanged from the 1960's. I also mentioned the Pegasus rocket being developed by Hercules/OSC in this regard. The person from NASA replied that the Russians were in the process of building a space shuttle and in his words "... were desperately trying catch up with us" !. His view was that the shuttle is all that is needed for now. In marked contrast, the person from the Commerce department was in complete agreement with me. He was very enthusiastic about the Pegasus project and said that they were trying to give all the encouragement they could. He went so far as to say that had the Saturn Vs not been scrapped, they would have probably been cheaper than the shuttle. I can tell you that I was more reassured by the Commerce department than NASA ! R. Anand Internet: anand@amax.npac.syr.edu Bitnet: ranand@sunrise ------------------------------ Date: 16 Aug 88 01:24:19 GMT From: markh@csd4.milw.wisc.edu (Mark William Hopkins) Subject: Space Bloopers In article <1049@cfa237.cfa250.harvard.edu> mcdowell@cfa250.harvard.edu (Jonathan McDowell) writes: >From article <62689@sun.uucp>, by fiddler%concertina@Sun.COM (Steve Hix): ... When space travel DOES become common, we're going to have to keep on a constant lookout for the remains of all the "missed shots"; because in space, what goes around, comes around ... ... > >AMS "Luna" Solar orbit, missed moon, called Luna-1 now. >Ranger 3 missed moon... What did they call IT after it missed the moon? >Ranger 5 missed moon... >Mariner 2 flew past Venus >Luna-4 missed moon, perturbed into solar orbit >Zond-1 failed Venus probe >Mariner 3 Mars flyby failed >Luna 6 Lunar soft lander missed moon >Venera 2 passed Venus, no data >Venera-3 HIT Venus, no data BULLSEYE! (20 years is enough time to look back and laugh.) ------------------------------ Date: 15 Aug 88 19:57:18 GMT From: tektronix!tekcae!vice!keithl@ucbvax.berkeley.edu (Keith Lofstrom) Subject: Re: SDI, Asats, and access to orbit bobmon@iuvax writes: > Years ago, somebody British proposed (in Punch? New Scientist? > Lancet?) a nice, cheap anti-ICBM solution to be used preemptively in > times of tension: Just throw a few tons of gravel into LEO. This sort of thing comes up about once a year. Time for some math, kiddies: Assume, by some miracle, we are able to orbit all these tons of gravel in a thin shell at 120 Km altitude (Radius = 6.5e6 meters). Assume a third stage moving at 4000 meters per second and still boosting, 5 meters long and 2 meters in diameter. Assume a 10 gram pellet moving at orbital velocity (8000 m/s) will destroy it and its warheads. The booster will spend (5 m)/(4000 m/s) or 1.25 msec traversing the shell. It will collide with any pellets in a patch 2 meters x 1.25 msec x 8000 m/s in area, or 20 square meters (crude description; see a good book on statistical mechanics for a better description yielding the same result). If N pellets are randomly distributed, they will have a density of N/(4*pi*R^2) per square meter, and the probability of finding one or more pellets in a given area is Probability = 1 - exp( - Area * density ) [see the book again]. This can be boiled down to the following equation: V missile 4 pi (Orbit Radius)^2 Number of pellets = --------- * --------------------- * -ln( 1 - Probability ) V orbit Area Missile for a 25% intercept rate (typical SDI number) about 8e12 pellets will be needed; about 80 million tons. More than "a few tons". For a 99.9% intercept rate (as claimed by many Anti-SDI folk) about 2 billion tons will be needed. ---- Smart interceptors (which can cover vastly more territory) are a whole different kettle of fish. If the booster has been visible for 60 seconds, and the interceptor can change velocity by 2000 meters/second in that time, it can intercept boosters over a "patch" of around 1e10 square meters. A 25% intercept rate would require 15,000 interceptors. ---- Please don't construe this message as being pro-SDI. Most bureaucrats and their political allies live in cities. The only way to eliminate this infestation may be for them to fry each other, as they seem hell-bent to do. If it wasn't for all the innocent people in cities it might even be a good idea :-). Hopefully, I just caused apoplexy for a few of the deserving :-). I DO want to show that space is a BIG place; the Earth is not too small, either. Village-scale thinking doesn't work any more. You have to do some math until the new scale of things gets imbedded in the culture; "common sense" isn't calibrated in this regime. -- Keith Lofstrom ...!tektronix!vice!keithl keithl@vice.TEK.COM MS 59-316, Tektronix, PO 500, Beaverton OR 97077 (503)-627-4052 ------------------------------ Date: 16 Aug 88 01:46:13 GMT From: stsci!berman@noao.edu (Mike Berman) Subject: Not in the line of duty Ten of our astronauts' deaths have been widely publicized - namely the three aboard Apollo 1 and the seven aboard the Challenger. I'm curious as to who is no longer with us as the result of a more "normal" demise? Are all of the crews of the successful Mercury, Gemini, Apollo, and shuttle missions still alive? -- Space Telescope Science Institute, Baltimore, MD 21218 Mike ARPA: berman@stsci.edu BITNET: berman@stsci Berman UUCP: {arizona,decvax,hao}!noao!stsci!berman SPAN: {SCIVAX,KEPLER}::BERMAN ------------------------------ Date: 16 Aug 88 01:41:15 GMT From: vsi1!unisv!vanpelt@ames.arc.nasa.gov (Mike Van Pelt) Subject: Re: SETI: Why don't we hear anything? In article <1112@ndsuvax.UUCP> nekinsel@ndsuvax.UUCP (Peter Kinsella) writes: > Aren't we making a few rather large assumptions. If we assume that >life exists elswhere in the universe. > 1. That the warring society can travel to conquer the broadcasting > world before that society developes sufficent technology to defend > itself. (faster then the speed of light ?) > 2. That it can travel in such numbers as to conquer a whole planet. > 3. If it had the technology to transfer enough people to take over > the planet of a lesser thechnology what would it gain ? > (welfare recipients? ) Who knows? Now, I don't really believe this, but suppose the warlike society wasn't interested in conquest, just in extermination? There's lots of talk about making self-replicating explorers to go through all the galaxy collecting data and eventually returning it to Earth -- Suppose a sufficiently xenophobic civilization decided to use the technique for eliminated threats/rivals? You can postulate that they get along fine with each other, but are horrified at the idea of "others", so the "destroy themselves before they advance that far" argument wouldn't hold. Presumably it wouldn't be all that difficult for an advanced civilization to build probes that would be more than a match for any civilization that had only a few years before mastered the use of radio, on which the probes would home in. I like to think of this as preposterously unlikely. (After all, we've been broadcasting like mad for decades, and haven't been blasted yet.) But then again, there's all those Biilyons and Biilyons * of stars out there, for all those Biilyons and Biilyons * of years ... and it only has to happen once for us all to be in deep yoghurt. -- * "Biilyons and Biilyons" is a trademark of Carl Sagan Enterprises, Inc. -- Mike Van Pelt When the fog came in on little cat feet Unisys, Silicon Valley last night, it left these little muddy vanpelt@unisv.UUCP paw prints on the hood of my car. ------------------------------ Date: 15 Aug 88 22:48:43 GMT From: phri!dasys1!tbetz@nyu.edu (Tom Betz) Subject: Re: space news from Juen 27 AW&ST In article <1988Aug11.044242.285@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: > The Chinese have just signed their first firm commercial >launch deal, to launch AsiaSat 1 (the former Westar 6, retrieved by the >shuttle in 1985) as Asia's first regional comsat, with a Hong Kong / >British consortium.) I think the most significant bit of news this month is contained in the sentence above... China has the honor and privilege of launching the first remarketed used communications satellite in the history of space technology! Let us hope there will be many more such launches to follow. -- "Through practice, I have become one of the |Tom Betz better liars in the English language. |ZCNY, Yonkers, NY 10701-2509 I wouldn't say it if I didn't know it wasn't true" |UUCP: tbetz@dasys1.UUCP or - Emmanuel Transmission - | ...!cmcl2!phri!dasys1!tbetz ------------------------------ End of SPACE Digest V8 #337 *******************