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 ; Mon, 1 Jul 91 05:23:47 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 1 Jul 91 05:23:43 -0400 (EDT) Subject: SPACE Digest V13 #762 SPACE Digest Volume 13 : Issue 762 Today's Topics: Re: A Space Science letter Re: Pioneer Venus ? When Is Next Shuttle Launch? Re: Access to Space Manned Space Flight Re: Access to Space Re: Access to Space Re: anti-gravity? Re: Slingshot effect Re: Body Mass Measurements Re: Mars "face" Re: Fred's Operatic Death 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: 18 Jun 91 00:11:07 GMT From: sequent!muncher.sequent.com!szabo@uunet.uu.net Subject: Re: A Space Science letter In article <328@hsvaic.boeing.com> eder@hsvaic.boeing.com (Dani Eder) writes: >If the committees are too dumb to understand this, we need to educate >them fast, since projects winding down, like Mars Observer, will get >unneeded windfalls, while those ramping up will be stalled. Congress has to cover a wide range of topics including DoD, DOE, Commerce, Agriculture, EPA, etc. etc. It cannot be expected to understand details of planetary missions, any more than a rocket engineer can be expected to be well-versed in tort law. It is up to the NASA leadership to provide an intelligent budget and guidance on these issues. They have failed to do so. On this topic, is there any way for space explorers to transfer money "under the covers" to provide the funds where they are needed? For example, CRAF work performed under the MO budget line, etc. -- Nick Szabo szabo@sequent.com Embrace Change... Keep the Values... Hold Dear the Laughter... These views are my own, and do not represent any organization. ------------------------------ Date: 18 Jun 91 03:24:20 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!think.com!snorkelwacker.mit.edu!bloom-picayune.mit.edu!pgf%space.mit.edu@ucbvax.Berkeley.EDU (Peter G. Ford) Subject: Re: Pioneer Venus ? In article <1991Jun17.224627.3146@ists.ists.ca> white@nereid (H. Peter White) writes: >I've heard rumors lately that Pioneer Venus will be sent into the atmosphere to >collect data for future Magellan work. I guess this would mean that Pioneer >Venus will collect data till the very end. >Anyone else heard anything about this, or did I hear wrong? You've got it half right--the Pioneer Venus spacecraft will indeed be captured by the Venus atmosphere, and burn up, sometime next fall, but it won't be deliberate... the spacecraft ran out of fuel long, long ago, (1980, I think) and its orbit has been wandering ever since. Its last few months will be closely monitored by Magellan engineers (among others), in order to plan for an aero-breaking manoeuver in which the Magellan spacecraft (which *does* have plenty of reserve fuel), will dip into the fringes of the Venus atmosphere in order to turn its current elliptical orbit into a more nearly circular one, which is desired in order (a) to obtain high quality measurements of the Venus gravity field, and (b) to increase radar resolution in polar regions. Peter Ford MIT and Magellan Project (also Pioneer Venus, a long time ago). ------------------------------ Date: 18 Jun 91 19:03:01 GMT From: ns-mx!ccad.uiowa.edu!koch@uunet.uu.net (Peter Koch) Subject: When Is Next Shuttle Launch? When is the next scheduled space shuttle launch? ------------------------------ Date: 18 Jun 91 18:29:34 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!think.com!yale.edu!ox.com!hela!aws@ucbvax.Berkeley.EDU (Allen W. Sherzer) Subject: Re: Access to Space In article <1991Jun18.172719.26033@sequent.com> szabo@sequent.com writes: >>Communications satellites are a pretty loose defintion of 'industry'... >Interesting. This ("loosely" defined :-) self-sustaining industry is $6 >billion per year. ^^^^^^^^^^^^^^^ It is a big industry but it is by no means self-sustaining. Buyers of launch services only pay the incrimental cost of their launches. They use huge amounts of infrastructure provided by nasty central planners (some of it constructed to support evil manned space). This is true for every launch proveder in the world today. If we did it your way there wouldn't be any launchers at all. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer | DETROIT: Where the weak are killed and eaten. | | aws@iti.org | | +---------------------------------------------------------------------------+ ------------------------------ Date: 18 Jun 91 19:06:41 GMT From: agate!bandit!wayne@ucbvax.Berkeley.EDU (Wayne Lee) Subject: Manned Space Flight Seeing as how I cannot seem to access Mr. Nick Szabo's network through the mail, I am posting this. I think I and a lot of others out there would be especially interested in EXACTLY what aspects (if any) of manned space flight including the shuttle does he support as "useful". Wayne Lee ------------------------------ Date: 18 Jun 91 21:03:50 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!caen!ox.com!hela!aws@ucbvax.Berkeley.EDU (Allen W. Sherzer) Subject: Re: Access to Space In article <1991Jun18.195748.27968@sequent.com> szabo@sequent.com writes: >Oh boy, now we're down to "good vs. evil". I'm just using your own words Nick. If you don't like them then don't use them. As to the rest of it, I am just pointing out that if the standards you apply to projects you don't like where applied to projects you do like, then they wouldn't have them either. Communication satellites are NOT self sustaining because they only pay incrimental launch costs. This is true for both the US and all world providers. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer | DETROIT: Where the weak are killed and eaten. | | aws@iti.org | | +---------------------------------------------------------------------------+ ------------------------------ Date: 18 Jun 91 21:55:11 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!rphroy!caen!spool.mu.edu!uwm.edu!ogicse!sequent!muncher.sequent.com!szabo@ucbvax.Berkeley.EDU Subject: Re: Access to Space In article <31548@hydra.gatech.EDU> ccoprmd@prism.gatech.EDU (Matthew DeLuca) writes: >Communications satellites are a service. The service sector of the >economy does not create signifigant real wealth, If the ability to communicate instantly across the planet does not constitute "wealth", what does? My particular business, Sequent, would lose over half of its revenues if we couldn't talk and send faxes to our European offices via satellite. Perhaps we could also say that steel mills and airplanes don't create real wealth, because that's merely manufacturing and transportation. Only farms that make food are real wealth. Ad absurdum. I find your arguments quite astounding. Perhaps what you are really trying to say is that, because the industry does not employ astronauts, you don't care about it? -- Nick Szabo szabo@sequent.com Embrace Change... Keep the Values... Hold Dear the Laughter... These views are my own, and do not represent any organization. ------------------------------ Date: 18 Jun 91 20:24:42 GMT From: Teknowledge.COM!unix!fritz.sri.com!stach@beaver.cs.washington.edu (John Stach x6191) Subject: Re: anti-gravity? 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] > > Interesting, but is it feasible? He claims that using nuclear >generators, it can be used to power spacecraft at a _constant_ 1G. > >Brett No, it works on the same ordinary principles that the one on Beyond 2000 works on. I will elaborate along with a simple (seemingly innocuous) modification that will eliminate the effect tomorrow (if someone else doesn't). HINT: The principle cannot be used for spacecraft although it can and has been used for aircraft. John I'm not antigravity, just proflight! ------------------------------ Date: 17 Jun 91 16:17:30 GMT From: sgeels@athena.mit.edu (Scott A Geels) Subject: Re: Slingshot effect In article <1991Jun15.032840.23428@athena.mit.edu> brndlfly@athena.mit.edu (Matthew T Velazquez) writes: >In la_carle@sol.brispoly.ac.uk >(Les Carleton) writes: > >>Can you please explain the "slingshot" effect as used on recent >>probes. I understand that it increases the velocity of the vehicle by >>making passes around the sun. I'm not a physics or Astrophysics major >>so it may seem a naiive question. What I don't understand is why the >>velocity increases. Surely if a pass of the sun is made, the energy >>conservation law will come into play and the vehicle will end up with >>the same velocity at its original distance from the sun as it had when >>left there (after launch?). > pseudo-proof: (pardon the ascii attempts at notation) V'(0,1) = velocity of spacecraft wrt the center of mass (CM), initial (0) and final (1) V (0,1) = velocity os spacecraft wrt the Earth (or Sun, or Solar System), initial (0) and final (1) V (CM) = velocity of center of mass (Venus) Definition of CM: (this is elementary physics) V(0) = V'(0) + V(CM) V(1) = V'(1) + V(CM) We want |V(0)| < |V(1)| , so that we gain energy Ergo, we want: |V'(0) + V(CM)| < |V'(1) + V(CM)| Example of how this can be the case: V'(0) = -5i(hat) V'(1) = +5i(hat) (note: these must have the same magnitude, by conservation of energy) V(CM) = +i(hat) |V(0)| = 4 |V(1)| = 6 Disclaimer: the numbers used here are bogus Therefore, net gain in velocity wrt the Earth! You can also use this to lose velocity. Scott Geels sgeels@athena.mit.edu sgeels%fred.den.mmc.com@everest.den.mmc.com ------------------------------ Date: 17 Jun 91 15:46:01 GMT From: mintaka!think.com!zaphod.mps.ohio-state.edu!swrinde!ctcvax.ccf.swri.edu!rocke!robison@bloom-beacon.mit.edu (Bob Robison) Subject: Re: Body Mass Measurements In article <1991Jun14.174759.9041@pmafire.inel.gov> alan@pmafire.inel.gov (Alan Herbst) writes: >>How are body mass measurements made aboard the shuttle in the weight- >>lessness of space? Is it the mirco-gravity at 180 miles up? >> >A good answer was received from: > >-- Ken Jenks, NASA/JSC/GM2, Space Shuttle Program Office > >"There are various devices used, including spring-based mechanisms which >"bounce" the crew member off a spring and calculate body mass through >f=ma, a "shaker" mechanism which moved crew members around and >calculated their mass by measuring inertia, and several others. I once >took a class from Dr. Thornton, a former astronaut (STS-51C) and >researcher of human physiology in space. Fascinating stuff. The main >problem with all zero-G mass measurement systems for humans has been >that people are flexible and mostly fluid. When measuring a flexible, >fluid-filled body by bouncing or shaking, that body tends to wiggle and >slosh, which throws off the mass measurements." > Sorry I'm lating responding to this -- I was out last week and am just now reading my news... Southwest Research Institute designed and built the Body Mass Measurement Device (BMMD) and the Small Mass Measuring Instrument (SMMI) that were aboard the Columbia on this past mission. Both of these devices work by supporting the mass to be measured on stiff springs. The mass is then deflected to one side and released which causes the mass to oscillate as the springs deflect one way and then the other (This is a side to side type of motion). The period of oscillation is measured very accurately and the mass is calculated from that period. As mentioned in the above post, the "sloshing" of one's internal organs is one of the problems with getting accurate measurements. On the BMMD, the subject sits in the device in a sort of "cannonball" position with knees pulled up close to the chest and is asked to tighten his/her muscles during the measurement. This minimizes the "sloshing" and provides better mass measurements. One thing I found interesting when we were researching how the Soviets did this, is that their version of the BMMD looked like a column with a plunger in it that moved up and down. The subject bent over the column with the (presumably) padded plunger pressed up against the subjects abdomen. The plunger then oscillated up and down -- doesn't sound like a fun way to be 'weighed' to me. BTW, the SMMI is used to measure masses in the range of about 1 gram to 1 kilogram, and is used for measuring chemicals, rodents, etc. The earlier version of the SMMI was called the SMMD. Both the SMMD and the BMMD were aboard SKYLAB. The SMMD required a connection to a TI calculator that ran the mass calculation. The SMMI is more automated and uses a built in computer to do the calculation and drive a dedicated display. This was the first flight for the SMMI, which I first worked on in 1979. Yes, it uses a state-of-the-art 6502 processor! Well, didn't mean to carry on so much -- but that is the background. And Dr. Thornton worked very closely with SwRI on the development of these mass measurement techniques. I believe work began on that in the late 60's. bob -- Bob Robison - Southwest Research Institute, Electromagnetics Div. brobison@swri.edu {sun!texsun, gatech!petro, uunet!cs.utexas.edu}!swrinde!dfsun1!robison ------------------------------ Date: 17 Jun 91 23:06:37 GMT From: tristan!loren@lll-winken.llnl.gov (Loren Petrich) Subject: Re: Mars "face" I've seen a copy of the Mars Face that was made available as a GIF. It looks remarkably like the face of a macaque monkey. I guess I'm not too impressed by it. $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ Loren Petrich, the Master Blaster: loren@sunlight.llnl.gov Since this nodename is not widely known, you may have to try: loren%sunlight.llnl.gov@star.stanford.edu ------------------------------ Date: 17 Jun 91 22:02:33 GMT From: sdd.hp.com!elroy.jpl.nasa.gov!jpl-devvax!ddc@decwrl.dec.com (Douglas Creel) Subject: Re: Fred's Operatic Death > >The fact that your employer, JSC, gets its revenues via the IRS >for astronaut projects makes me discount your "pro-manned" >statements. Quit wasting my tax money making self-serving posts to the >net. Quit wasting my money on engineer-welfare projects like Fred. Get a >real job. > > >-- >Nick Szabo szabo@sequent.com You sound like a desperately lonely person, Nick. I suggest you seek some professional counseling for this hostility problem of yours. As far as someone's postings being a waste of your tax paying dollars, well, Nick, you're not the only one who pays taxes on this net. Maybe we should clarify exactly what it is you consider an "engineer-welfare" project. What about me? I work for the Mars Observer project which is decidedly unmanned and would seem to fall under the auspices of one of your pet projects. Is this welfare for engineers and space scientists? I can't recall of ever hearing of welfare recipients who work for their living. What about all the scientists who work for NASA, or NOAA, or the NSF, or NIMH, or any one of the national labs. Are we all just a bunch of self-serving welfare recipients, be that self-serving "astronaut-groupies" or self-serving "science-weenies"? Please enlighten me Nick, so that this veil of ignorance which seems to surround all of us who consider the men and women who died on Challenger heroes and not misguided martyrs can be lifted. Douglas D. Creel Mars Observer Navigation Team Jet Propulsion Laboratory ------------------------------ End of SPACE Digest V13 #762 *******************