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 ; Fri, 5 Jul 91 04:10:10 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 5 Jul 91 04:10:03 -0400 (EDT) Subject: SPACE Digest V13 #786 SPACE Digest Volume 13 : Issue 786 Today's Topics: Re: Access to Space Re: Dark matter Re: Mining El Dorado GRO status report 5/20/91 Astro Soc Directory Re: Mission status report 6/5/91 Magellan status reports Re: anti-gravity? 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: 22 Jun 91 21:51:08 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!hela!aws@ucbvax.Berkeley.EDU (Allen W. Sherzer) Subject: Re: Access to Space In article <31591@hydra.gatech.EDU> ccoprmd@prism.gatech.EDU (Matthew DeLuca) writes: >>No, self-sustaining is not the same thing as profitable... >Okay, perhaps I missed it in the original post, but how did you come up >with the statement that comsats aren't self-sustaining? Let's go back to the original statement. Nick was saying that government construction of space infrastructure was wrong. He then used the example of communication satellites as a self sustaining use of space. All I am saying is that this is not the case; all satellites get lots of subsidies from those nasty central planners which Nick rails against. Without these subsidies there would be no space launches at all. The fact is that there is almost no private launcher development going on (and the few which are private are dependant on what amounts to government seed money). Ditto for launch facilites. If the governmrnt dropped all support the launch industry would colapse. The satellite buisness would soon follow. This means that there are no self sustaining space industries today. The question isn't government support vs no govenrment support rather the question is how should the government support the creation of an infrastructure which IS self sustaining. The government has done this many times in the past and we need to do it the same way today. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer | DETROIT: Where the weak are killed and eaten. | | aws@iti.org | | +---------------------------------------------------------------------------+ ------------------------------ Date: 21 Jun 91 07:48:20 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!emory!wa4mei!ke4zv!gary@ucbvax.Berkeley.EDU (Gary Coffman) Subject: Re: Dark matter In article <1991Jun15.031134.14353@ux1.cso.uiuc.edu> tbm19061@uxa.cso.uiuc.edu (Thomas B MacIukenas) writes: >lev@slced1.nswses.navy.mil (Lloyd E Vancil) writes: > >>And I was wondering, why cant "dark matter" be planets, rocks, comets, etc etc? > >Well, let's see-- >Planets. These are only a small fraction of the mass of solar systems, > which are already accounted for, so they can't be the dark matter. >Rocks. I don't see any reason why not. >Comets. These are just rocks which get too close to stars, so the same > comment applies. > >The only thing I can think of is that since rocks/comets are formed of >matter which comes from dead suns, maybe what we know about star life >cycles says that not enough rocky material could have been formed already. Bingo! According to the theories postulating dark matter, it has to have formed around the time of symetry breaking immediately after the Big Bang. As such, it must be really strange stuff indeed. Gary ------------------------------ Date: 21 Jun 91 07:23:00 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!emory!wa4mei!ke4zv!gary@ucbvax.Berkeley.EDU (Gary Coffman) Subject: Re: Mining El Dorado In article <1991Jun16.195153.9959@stb.info.com> charles@stb.info.com (Charles (from bbs)) writes: >How do we mine the El Dorado asteroid ? Is it one big stainless steel >nugget, or is it differentiated ? Either way, I propose blasting it >to pieces using high explosives. If it is a homogeneous stainless >steel nugget I would drill a hole right to the center and insert a >small nuclear device. If it is differentiated, conventional >explosives might suffice. Nuclear gives more bang per pound, so >better than chemical and takes less propellant to send it to El >Dorado. >We do not want lots of fragments flying everywhere, all we need >is to create a powerful shock wave to disrupt the asteroid structure. >The shock should be small enough that gravity will continue to hold >the pieces together. We could literally surround the asteroid with a >safety net to ensure most of it is retained. Once shocked the >pieces can be individually transported or processed by a robot >smelter. If it is well differentiated it might be possible to >visually separate out nuggetts of rare metals, and discard the >silicates and iron. A weak acid could dissolve reactive metals ( >alkali earth and alkali metals and iron ) and heavier metals like Gold >and Platinum would be beneficiated. If desired the acid solution >could be electrolysed with low energy to recover the lighter metals. >Beneficiating by weight might be possible, would have to spin the > nuggetts in a centrifuge to find out how dense they are. Each nugget > could also be scanned by alpha particle back scattering or other > radio-spectroscopy means, and then sorted into valuable and less > valuable bins. Probably cheaper than electrolysis too. Most efficient > might be to use minimum size ( ie critical mass only ) nuclear > charges, and progressively shock parts of El Dorado, that allows more > margin for error in case we guess wrong about the quantity of shock > needed - do not want to over do it ! Would need rather a lot of > diamond drills if it is steel, maybe somebody could design a laser > cutting torch so we can burn our way in. How about a deliberate > nuclear pile meltdown on the surface, the hot pile melts to the center > via gravity - al la China Syndrome. The asteroid would have so little self gravity that it wouldn't be able to hold on to pieces blasted loose, nor would a melted pile sink to the center in less than geologic time. After a nuclear meltdown, or even a nuclear explosion, the gold, platinum and nickel iron would find no market on Earth, and likely no use in orbit for at least 500 years. Using nukes in this way means you better consider your investment *very* long term. In general, I wouldn't want you as mining engineer on my project. :-) Mining something this big in space is really novel. Nobody's ever done anything similar and totally new techniques will have to be developed. Don't let me dampen your speculations, this is really fresh ground and really practical ideas may sound wild at first glance. Gary ------------------------------ Date: 23 Jun 91 00:02:02 GMT From: cis.ohio-state.edu!pacific.mps.ohio-state.edu!linac!mp.cs.niu.edu!ux1.cso.uiuc.edu!rs6000.cmp.ilstu.edu!ejbehr@ucbvax.Berkeley.EDU (Eric Behr) Subject: GRO status report 5/20/91 [even though the reports are supposed to be "weekly", this is the newest one on SpaceLink... E.B.] ----- GRO Weekly Status 5/20/91 NOTE: This will be the last regularly scheduled status report. GRO news will be released when significant scientific discoveries have been made or when it is warranted by the performance of the spacecraft. GAMMA RAY OBSERVATORY (GRO) WEEKLY STATUS REPORT #5 May 20, 1991 The Flight Operations Team in the Payload Operations Control Center, Goddard Space Flight Center, Greenbelt, Md., reports the Gamma Ray Observatory (GRO) is performing well. GRO orbits Earth at an altitude of 287 x 280 statute miles (462 x 451 kilometers). All four of GRO's instruments have been calibrated. Science operations began Thursday May 16, 1991 with the observatory pointed toward a pulsar in the Crab Nebula. The Phase 1 viewing plan of the science operations is a full-sky survey expected to last fifteen months. Analysis of the propulsion system pressure transducer and valve misconfiguration anomalies continues. The system is stable and the observatory will continue to be operated in its present configuration for an indefinite period. The propulsion system anomalies do not affect the spacecraft's operation. Four detectors in the Imaging Compton Telescope (COMPTEL) instrument have not been activated at this time, leaving the instrument at 67% of full efficiency. The detectors are experiencing high levels of noise associated with out-gassing. Out-gassing is a normal process. One of the detectors will be activated this week and all four are expected to be activated by the end of May. The Flight Operations Team anticipates that COMPTEL will be functioning at 100 percent efficiency once the equipment is activated. -- Eric Behr, Illinois State University, Mathematics Department Internet: ejbehr@rs6000.cmp.ilstu.edu Bitnet: ebehr@ilstu ------------------------------ Date: 22 Jun 91 07:21:22 GMT From: agate!usenet.ins.cwru.edu!magnus.acs.ohio-state.edu!zaphod.mps.ohio-state.edu!mips!spool.mu.edu!munnari.oz.au!bruce!monu0.cc.monash.edu.au!vaxc.cc.monash.edu.au!apm945h@ucbvax.Berkeley. Subject: Astro Soc Directory Hi, me again. I'm an inquisitive mathematics honours student, and find myself often reading scientific papers formy project and other areas of interest. Since I last requested help in finding two American scientists, I was e-mailed by several people giving me their e-mail addressess from The American Astronomical Society 1991 Membership Directory. To save me bugging people all the time, I was wondering if it was possible for me to get hold of a copy, perhaps there is a version in the form of a datafile that could be e-mailed to me??? Thanks in advance, The Gryphon........... Mick Pope Dept of Applied Mathematics, Monash University, Clayton 3168, Victoria Australia e-mail apm945h@vaxc.cc.monash.edu.au ------------------------------ Date: 21 Jun 91 04:30:27 GMT From: ucivax!p4tustin!ofa123!p201.f208.n103.z1.fidonet.org!Mark.Perew@ucbvax.Berkeley.EDU (Mark Perew) Subject: Re: Mission status report 6/5/91 > > [...deleted section...] and whether the > > seal poses any threat to payload bay doors closing has yet to > > be determined. However, that possibility is considered doubtful. > Wow, this biological studies mission seems to have gotten out of hand. > Imagine a loose seal blocking the payload bay doors - bark, bark!! :-) Wow, these unmanned planetary probe missions seem to have gotten out of hand. Imagine a partially deployed antenna blocking high-speed communications back to Earth and no astronaut on board to fix the problem - bark, bark!! (smiley omitted). - Mark Perew Mark.Perew@ofa123.fidonet.org -- Mark Perew Internet: Mark.Perew@p201.f208.n103.z1.fidonet.org Compuserve: >internet:Mark.Perew@p201.f208.n103.z1.fidonet.org -------------------------------------------------------------------------- ------------------------------ Date: 22 Jun 91 23:58:37 GMT From: att!linac!mp.cs.niu.edu!ux1.cso.uiuc.edu!rs6000.cmp.ilstu.edu!ejbehr@ucbvax.Berkeley.EDU (Eric Behr) Subject: Magellan status reports Someone asked me to upload some info on planetary missions (from the NASA SpaceLink BBS). It might be of interest to others, so I'm posting it here. Some of the reports are quite old, but they are the latest available ones. ----- MGN REPORT 6/17 AJS 6-17-91 9:00 AM MAGELLAN STATUS REPORT 1. The Magellan spacecraft is continuing to perform nominally. 2. Electrical power was down in the Denver Mission Support area so subsystem engineers are still checking the engineering telemetry from the weekend. 3. The star invalid counter incremented by only three, indicating that most STARCALs and DESATs continue to be very successful. 4. Magellan is currently operating in a mode which includes two 55-minute hide periods, and using a right look radar approach in order to map area around the South Pole. This will continue for the next ten days. MGN REPORT 6/18 AJS 6-18-91 9:00 AM MAGELLAN STATUS REPORT 1. The Magellan spacecraft and its radar system are performing nominally. All starcals and desats were successful. 2. The weekly command sequence M1170 will be sent to the spacecraft later today. It will continue the two 55- minute hide periods for thermal control, and mapping of the area from 45 degrees south latitude to the South Pole. 3. The next command sequence, M1177, will shift to left- looking radar mapping and 32 minute hide periods as we begin to fill in the Superior Conjunction Gap. MGN REPORT 6/19 AJS 6-19-91 9:00 AM MAGELLAN STATUS REPORT 1. The Magellan spacecraft and its radar system are performing nominally. All starcals and desats were successful. 2. The weekly command sequence M1170 was successfully uplinked to the spacecraft yesterday. It continues the two 55-minute hide periods for thermal control, and mapping of the area from 45 degrees south latitude to the South Pole. 3. Next week's sequence, M1177, will shift to left-looking radar mapping and 32-minute hide periods as we begin to fill in the Superior Conjunction Gap. MGN REPORT 6/20 AJS 6-20-91 9:00 AM MAGELLAN STATUS REPORT 1. Magellan spacecraft performance continues to be excellent. 2. All STARCALs and DESATs yesterday were successful except for one star reject on orbit #2415. 3. Tomorrow spacecraft controllers will perform the routine update to the Radar Control Parameter File. 4. Magellan is now in its 1934th mapping orbit, with over 200 since we switched to right-look mapping. -- Eric Behr, Illinois State University, Mathematics Department Internet: ejbehr@rs6000.cmp.ilstu.edu Bitnet: ebehr@ilstu ------------------------------ Date: 23 Jun 91 05:24:53 GMT From: wdl30!ekman@ford-wdl1.arpa (Donald Ekman) Subject: Re: anti-gravity? In article <25547@unix.SRI.COM> stach@fritz.sri.com.UUCP (John Stach x6191) writes: >In article <1991Jun18.004625.156@falcon.aamrl.wpafb.af.mil> bkottmann@falcon.aamrl.wpafb.af.mil (Brett Kottmann) writes: >> >> A researcher in Scotland has developed a device that harnesses >>gyroscopic energy to lift a device against gravity--antigravity for all intents >>and purposes. >> >> [... details deleted] Has David Tiberio moved to Scotland recently? -- Donald E. Ekman, Space Systems/Loral, Palo Alto, CA ekman@wdl30.wdl.loral.com ------------------------------ End of SPACE Digest V13 #786 *******************