Subject: Space-tech Digest #96 Contents: Rich Schroeppel ion engines Jay Skeer fwd: The Lunar Society Jonathan Leech Dole accretion model code Dale Amon polar beanstalks Marc Ringuette orbital mechanics code Dale Amon hybrids ------------------------------------------------------------ Date: Thu, 26 Dec 91 12:48:16 MST From: "Richard Schroeppel" To: space-tech@cs.cmu.edu Subject: ion engines There's been recent discussion in Space-Digest about using mercury as reaction mass for ion engines. Query: Is the Hg accelerated & exhausted as Hg+ or as (Hg2)+? The gas phase is diatomic, as is the anion in (water) solution. This is relevant to discussion of the mass of the accelerated species, and the comparison with fullerenes. Rich Schroeppel rcs@cs.arizona.edu ------------------------------ From: Jay Skeer Reply-To: jay@markv.com To: space-tech@daisy.learning.cs.cmu.edu Subject: [71750.2413@compuserve.com: The Lunar Society] Date: Fri, 27 Dec 91 14:15:09 PST From: jay@hermix To: space-tech@daisy.learning.cs.cmu.edu Subject: [71750.2413@compuserve.com: The Lunar Society] I thought space-tech readers might be interested in this. I'd be interested in readers' perspectives of the book mentioned, and of the orginization. j' To: Extropians@gnu.ai.mit.edu From: "Russell E. Whitaker" <71750.2413@compuserve.com> Subject: The Lunar Society 21 Dec 371/1991 I just finished reading a paperback compilation of science fiction and non-fiction essays, edited by Jerry Pournelle, *Cities in Space* (Ace, 1991). In his after afterward to Jim Ransom's article "Access to Space: SSX", Pournelle writes: [beginning of excerpt] "...All of which is preparatory to a pitch: the L-5 Society has merged with the National Space Society (NSS), and has become yet one more part of the NASA cheering section. NSS now seems to have the typical Washington attitude that nothing of importance happens outside the Beltway, and nothing can be done without the government. As for me, as I watch The Incredible Shrinking Space Station, the redesign of things that weren't broken, and the general bureaucratic CYA attitude, I am convinced that NASA is the problem, not the solution. "Recall Dick Rhutan patting *Voyager*'s wing after his historic flight: 'See what free men can do', he said. "Well, we're going to try. Jim Ransom, Phil Chapman, and some of the other old L-5 enthusiasts have started The Lunar Society. The Society exists; it has a legal charter. It isn't precisely _looking_ for members, but we'll take them. We prefer people who want to do something. "There's no big membership-services group, because the organization has no full-time employees. If you want to register, it costs one hundred dollars, and the only thing you get for that money is our personal guarantee that we won't waste the money. If you're interested, the address is: The Lunar Society 3960 Laurel Canyon Blvd. Suite 372 North Hollywood, California 91604 Please don't write to ask for 'information'. We don't have any fancy brochures. Just hard-working people trying to put a colony on the moon in our lifetimes." [end of excerpt] Well, I'm game: my $100 check is on the way. Enough of us here are acquainted with Jerry to know this isn't a dodgy proposition. This message is being sent to several lists and individuals. [j': see distribution below, please try to maintain it to prevent people seeing multiple copies of it] Oh, and if anyone who receives this has a BIX account, please forward this to Jerry; his userid is 'jerryp'. Thanks. Distributing this at RAND, Xerox, Xanadu/Autodesk, Ames, and a few other places might not be wasted effort, now that I think of it.... Freedom, immortality, and the stars, Russell E. Whitaker 71750.2413@compuserve.com Communications Editor EXTROPY: The Journal of Transhumanist Thought Distribution: Extropians >INTERNET:extropians@gnu.ai.mit.edu Alcor >INTERNET:alcor@cup.portal.com Steven B. Harris [71450,1773] Foresight Institute >INTERNET:foresight@cup.portal.com Libernet >INTERNET:libernet@dartvax.dartmouth.edu Ralph Merkle >INTERNET:merkle@xerox.com Dan Spitzer [76276,27] Dean Tribble >INTERNET:tribble@xanadu.com [j'] space-tech >INTERNET:space-tech@daisy.learning.cs.cmu.edu ------------------------------ Date: Wed, 1 Jan 92 23:01:08 -0500 From: Jonathan Leech To: space-tech@cs.cmu.edu Subject: Dole accretion model code I converted Wales' planetary formation model code from BASIC to C++ and made it spit out PostScript. It should work with any current C++ compiler. It can be obtained by anonymous FTP from ftp.cs.unc.edu:pub/acrete.c. Jon (leech@cs.unc.edu) __@/ ------------------------------ Date: Thu, 16 Jan 92 14:51 GMT From: CSG0669@vax2.queens-belfast.ac.uk To: SPACE-TECH-REQUEST <@nsfnet-relay.ac.uk:SPACE-TECH-REQUEST@CS.CMU.edu> Subject: RE: Space-tech Digest #93 Subject: Polar beanstalks I'm surprised no one mentioned that there will be an increase in tension on the cables. Of course, if they meet at GEO, the angles will be rather small, but it still might be significant. (The cable tension is a vector and we have added another component) Also, mightn't there be some coriolis effects? And in opposing directions, which doubles the effect. Thus each cable will sag due to gravity AND one will sag East and the other West. I've a feeling the shape of this 3d curve could be a bit tricky... [ No, there aren't any Coriolis forces acting east/west here. Coriolis forces only occur when you _move_ in a gravity well. They act to push you up/down when you move east/west, and vice versa. Okay, there will be Coriolis forces when you send a payload up/down the cable, but that's the only time. --Marc ] ------------------------------ Date: Fri, 17 Jan 1992 17:20-EST From: Marc.Ringuette@DAISY.LEARNING.CS.CMU.EDU To: space-tech@cs.cmu.edu Subject: orbital mechanics code > Date: Fri, 17 Jan 92 13:50 PST > From: trost@reed.edu (Bill Trost) > To: space-tech-request@cs.cmu.edu > Subject: some interesting code? > > The Macintosh program to do orbital mechanics Karl Dishaw wrote is > available for anonymous ftp from ftp.reed.edu. You might want to put > it on daisy.learning.cs.cmu.edu and announce to the net its > availability. The filename is ~ftp/pub/OrbMech.sit.hqx. Done. You can get it from daisy.learning.cs.cmu.edu (128.2.218.26), file /usr/anon/public/OrbMech.sit.hqx. M. ------------------------------ Date: Fri, 17 Jan 92 21:06 GMT From: CSG0669@vax2.queens-belfast.ac.uk To: space-tech@cs.cmu.edu Subject: RE: Space-tech Digest #94 Sender: mnr@DAISY.LEARNING.CS.CMU.EDU Subject: Hybrids I'm aware of a fellow who has built and tested some AL-H20 engines. Initial test was with a Li igniter. It causes the water to dissociate and gets the temp high enough for the Al to start burning, and once it gets going the temp is high enough to dissociate the water oxidizer as it enters the chamber. I believe he was going to go to a different igniter. (Is it methyl something or other?) That would give him a restart capability. Design was dead cheap. [If Bev is listening, any rumors of Ichor lately?] Dale Amon ------------------------------ End of Space-tech Digest #96 *******************