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, 1 May 91 01:27:52 -0400 (EDT) Message-ID: <4c7Z7CO00WBwQ1Pk5E@andrew.cmu.edu> Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 1 May 91 01:27:43 -0400 (EDT) Subject: SPACE Digest V13 #485 SPACE Digest Volume 13 : Issue 485 Today's Topics: Re: Saturn V and Design Reuse: Saturn VI? Re: Transportation Tethers (Beanstalks) Scientific Humor NASA Prediction Bulletins: Space Shuttle Re: Terraforming Mars? Why not Venus? Re: Gas Guns and Tethers Gif files Re: Saturn V vs. ALS Re: new gifs available Re: HOW TO TELL IF Re: Galileo works? 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: 30 Apr 91 22:26:10 GMT From: celit!dave@ucsd.edu (Dave Smith) Subject: Re: Saturn V and Design Reuse: Saturn VI? In article <1991Apr25.210855.20189@csl.dl.nec.com> baker@csl.dl.nec.com (Larry Baker) writes: >My question -- and, I guess, my point -- is this: Why rebuild the Saturn V? >Why not take the Saturn V design and incrementally improve it, with the advantages >of 30 years' improvement in practice, experience and technology? > >Don't rebuild it. Don't start over. Improve the existing design? In my mind there is no _technical_ reason why we could not build a better booster today. We have the technology and plenty of smart people. However, the politics (not just government, but company internal) that seem to inevitably follow these projects ensure that we can't. The revival of the Saturn V, in my mind, is being pushed to avoid the endless paper studies and creeping featurism that have plagued all the other space initiatives in the last 20 years. Once we have a working Saturn V, then we can go back and improve it to be the Saturn VI. Let's get something that flies first, eh? -- David L. Smith FPS Computing, San Diego ucsd!celit!dave or dave@fps.com "It was time to stop playing games. It was time to put on funny hats and eat ice cream. Froggie played his oboe" - Richard Scarry ------------------------------ Date: 30 Apr 91 18:39:07 GMT From: csus.edu!wuarchive!zaphod.mps.ohio-state.edu!samsung!umich!sharkey!fmsrl7!wreck@ucdavis.ucdavis.edu (Ron Carter) Subject: Re: Transportation Tethers (Beanstalks) In article <1991Apr27.232403.11033@milton.u.washington.edu> wiml@milton.u.washington.edu (William Lewis) writes: >and falls on your insurer?) ... not to mention the incredibly >difficult job of putting the beanstalk *up* in the first place. Actually, you would build a beanstalk down from geosync (or, rather, in both directions from geosync, up and down both at once). When the bottom end touches Earth, you anchor it firmly. Dealing with tidal effects and dynamic instabilities is left as an exercise for the student. ;-) ------------------------------ Date: 30 Apr 91 04:36:21 GMT From: att!emory!ducvax.auburn.edu!bbayn@ucbvax.Berkeley.EDU Subject: Scientific Humor In the beginning, GOD created Aristotle, and Objects at rest, tended to remain at rest Objects in motion, tended to come to rest And soon, everything was at rest. And GOD saw that it was boring. Then GOD created Newton, And objects at rest, tended to remain at rest, And objects in motion, tended to remain in motion, And energy was conserved and matter was conserved, And momentum was conserved. And GOD saw that it was conservative. Then GOD created Einstein, And fast things became short, Straight things became curved, And the Universe was filled with inertial frames. And GOD saw that it was relatively general, But some of it was especially relative. Then GOD created Bohr, And there was The Principle, And The Principle was quantum, And everything was quantified, But some things were still relative. And GOD saw that it was confusing. Then GOD would have created Ferguson, And Ferguson would have Unified, And he would have fielded a theory, And all would have been one. But it was the seventh day, and GOD rested, And objects at rest tend to stay at rest. - Anonymous ========================================================================== Disclaimer? I don't need no stinkin' disclaimer! Brendan C. Bayne bbayn@ducvax.auburn.edu brendanb@eng.auburn.edu Making it happen! ========================================================================== ------------------------------ Date: 30 Apr 91 23:11:38 GMT From: udecc.engr.udayton.edu!blackbird.afit.af.mil!tkelso@tut.cis.ohio-state.edu (TS Kelso) Subject: NASA Prediction Bulletins: Space Shuttle The most current orbital elements from the NASA Prediction Bulletins are carried on the Celestial BBS, (513) 427-0674, and are updated several times weekly. Documentation and tracking software are also available on this system. As a service to the satellite user community, the most current elements for the current shuttle mission are provided below. The Celestial BBS may be accessed 24 hours/day at 300, 1200, or 2400 baud using 8 data bits, 1 stop bit, no parity. STS 39 1 21242U 91 31 A 91120.18973379 .00205814 26710-4 25599-3 0 67 2 21242 56.9956 281.3569 0009980 259.2276 279.5206 16.07262807 275 -- Dr TS Kelso Assistant Professor of Space Operations tkelso@blackbird.afit.af.mil Air Force Institute of Technology ------------------------------ Date: 1 May 91 00:09:58 GMT From: munnari.oz.au!metro!grivel!gara!bsercomb@uunet.uu.net (Katani) Subject: Re: Terraforming Mars? Why not Venus? mars. There is a huge amount of corrosive acid on the surface, let alone the stuff in the atmosphere. If you were to convert the atmosphere, there would still be acid/methane etc.etc.etc vaporising from pools on the surface. The other problem is the vulcanism and earthquakes. there is no way you are going tobe able to stop them with a little [little?] catalyst. ther are mainly a result of the spin of the planet and the greater gravitational disturbences of the sun.hence, you would clean up the p lanet but have your buildings flattened fast. If you were really set on the terraformation of Venus, and you had some pretty hot technology, you could calculate the interference caused by the sun and the magnetic flow caused by the planets spin and SLOW DOWN THE PLANET to the required level. [about that of earth] and the vulcanism/earthquakes would slow and probably drop to a more manageable level after a while [while defined as a minimum period of a few centuries!!]. Well, that's my eight cents worth. katani. ------------------------------ Date: 30 Apr 91 03:33:23 GMT From: agate!bionet!uwm.edu!wuarchive!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!utdoe!torag!w-dnes!waltdnes@ucbvax.Berkeley.EDU (Walter Dnes ) Subject: Re: Gas Guns and Tethers eder@hsvaic.boeing.com (Dani Eder) writes: > > This ignores the fact that you do not have to have a tether all > the way from orbit to the ground. A shorter tether hanging vertically > in orbit will have it's lower end moving sub-orbitally. A launch > system then only has to reach the bottom of the tether, rather than > orbit. Anything that makes a launch vehicles' job easier is > beneficial. The reminder of the ride to orbit (which is at the > center of mass of the tether) can be via elevator. > ___ |___| Space I think that you've fallen into the old | station "pull-yourself-up-by-your-bootstraps" fallacy. Here's a | simplified diagram of the situation, just before the | launch vehicle grabs the bottom of the tether. Assuming | that the mass of the tether is small relative to the main | station, the centre of mass of station+tether will be near | the space station itself. When the shuttle grabs the | |===| tether, we have a new body, i.e. station+tether+shuttle. shuttle You have three problems to deal with... Theoretical problem 1) The centre-of-mass of the combined structure has instantaneously dropped closer to the earth's surface without the orbital velocity increasing. The result should be a lower orbit. Theoretical problem 2) Remember my "Summary:" line about no boostrapping? As the shuttle climbs the tether, the space-station+tether descend a bit. Since we're dealing with a closed system, the centre-of-mass must remain in the same orbit. Practical problem 1) Conservation of angular momentum... Unless the shuttle matches velocity *VERY* closely with the station, the two bodies will be spinning around each other at some horrendeous rpm's by the time the shuttle has climbed all the way up the tether. The theoretical problems are where many "perpetual-motion machines" trip over reality. It takes X joules of work to lift a specific payload to a specific orbit. TANSTAAFL... There Ain't No Such Thing As A Free Lunch. Rather than a tether, how about a "Tower of Babel", reaching up to GEO ? Technologically impossible, but good for a sci-fi story or two. At least in the stories, you could take an elevator to the top. Where are you when we need you Monsieur Eiffel ? ------------------------------------------------------------------------ waltdnes%w-dnes@torag.UUCP <--- Use this address until I get officially mapped. hybrid!torag!w-dnes!waltdnes <--- The hard way 73710.3066@compuserve.com <--- Compuserve ------------------------------ Date: Tue, 30 Apr 1991 08:49 EDT From: DOUG LUTE Subject: Gif files X-Organization: Indiana University of Pennsylvania X-Envelope-To: space+@andrew.cmu.edu X-Vms-Cc: PXZYLCB Hello, I had trouble getting the GIF files from ames.arc.nasa.gov. The problem was that I couldn't get to directory /pub/space/cdrom. I'm probably doing something stupid, but I tried cd /pub/space/cdrom, and cd /pub/space, but only cd /pub worked. Can anyone help? Thanks... <> "Dave, I can feel it. I can feel it, Dave, you're destroying my mind, Dave..." - HAL 9000, "2001" ------------------------------ Date: 30 Apr 91 18:28:39 GMT From: pasteur!agate!stanford.edu!snorkelwacker.mit.edu!spool.mu.edu!sol.ctr.columbia.edu!emory!ox.com!fmsrl7!wreck@ucbvax.Berkeley.EDU (Ron Carter) Subject: Re: Saturn V vs. ALS In article <1128@opus.NMSU.Edu> bwebber@charon.UUCP (K.MacArthur working for bwebber) writes: >In article <1991Apr24.234249.10940@nntp-server.caltech.edu> krs@dullea.ipac.caltech.edu (Karl Stapelfeldt) writes: >> The problem with resurrecting the Saturn V today is the same >>same problem that caused the launcher to go out of production in the >>1970s : It is just too damn big for our current needs.... >>It clearly is not worth rebuilding the Saturn V with >>this kind of expected utilization. I am reminded of the estimate that all of the world's calculational needs could be satisfied by a of computers. Needless to say, that estimate has turned out to be low by many orders of magnitude. > I disagree. What about the possibility that once a large and >reliable launcher is proven that more things will be created to fill the >available capacity? Since many payloads are fussy about their exact orbit, there is not too much prospect for piggy-backing payloads in general. However, industrial items such as stand-alone electrophoresis boxes, protein crystallization and large-scale semiconductor processing would appear to be excellent candidates for general hitch-hiker payloads at first blush. If the "standby" space were sold for $500/lb, the equipment could be heavy and rugged yet still pay for its launch. This would eliminate a great deal of R&D work to squeeze weight out of the equipment itself. ------------------------------ Date: 29 Apr 91 16:19:17 GMT From: pasteur!agate!bionet!uwm.edu!wuarchive!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!ducvax.auburn.edu!eng.auburn.edu!bh@ucbvax.Berkeley.EDU (Brian Hartsfield) Subject: Re: new gifs available Is there a GIF viewer that displays pictures in SVGA (PD or shaeware preferred ) and where can I get it from? bh@eng.auburn.edu / ------------------------------ Date: 1 May 91 04:05:48 GMT From: stanford.edu!agate!lightning.Berkeley.EDU!fcrary@decwrl.dec.com (Frank Crary) Subject: Re: HOW TO TELL IF Re: Galileo works? In article <32430@usc> robiner@mizar.usc.edu (Steve Robiner) writes: >Can't NASA use Hubble (if its still working then :> ) to look at >Galileo on its next flyby past Earth. It'll be moving pretty damn >fast, but they must be able to compensate for Hubble's own orbital >rotatioi and Earth's movement through space (which has got to be a lot faster >than galileo will be moving). In fact, Hubble can not compensate for Galileo's velocity. What is important is ANGULAR speed. While Hubble and Earth are moving through space quite fast (as are the objects which Hubble looks at), Hubble is also very very far away from the things it observes. As a result these is effectivly NO angular motion (like watching a distant mountain from a car). Galileo, on the other hand, will be both moving very fast AND be very close to Hubble. I do not believe Hubble could slew fast enough to tract Galileo. Frank Crary UC Berkeley ------------------------------ End of SPACE Digest V13 #485 *******************