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 ; Sat, 15 Jun 91 04:19:38 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sat, 15 Jun 91 04:19:32 -0400 (EDT) Subject: SPACE Digest V13 #651 SPACE Digest Volume 13 : Issue 651 Today's Topics: Re: satellite refuelling Re: Good for the Japanese Re: 3D views from 2d data Re: Privatization Re: Babies in Space NASA and Criticism Re: Good for the Japanese Re: RE: USF, Inc. : Brought to you by the Re: Calculating delta-V Re: Self-sustaining infrastructures Re: NASA and Criticism Re: satellite refuelling 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 May 91 14:54:38 GMT From: sequent!muncher.sequent.com!szabo@uunet.uu.net Subject: Re: satellite refuelling In article <1991May29.200006.20776@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >... >One has to weigh the cost of a >refuelling mission against the cost of a larger launcher and larger >satellite; it is not at all clear that the balance is always against >refuelling. You missed another option, which is to decrease the payload mass in order to allow more stationkeeping fuel for the same launcher. When we are talking $billions in satellite redesign and infrastructure to develop refueling, it is pretty clear that using larger launchers or decreasing payload mass when extra lifetime is needed is preferable to adding the mass and complexity of refuelable tanks, and performing refueling operations them. For most satellites, the cost of a refueling mission will not be significantly smaller than the cost of launching a new generation, more capable satellite. -- Nick Szabo szabo@sequent.com "If you understand something the first time you see it, you probably knew it already. The more bewildered you are, the more successful the mission was." -- Ed Stone, Voyager space explorer ------------------------------ Date: 30 May 91 17:21:20 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!jato!vsnyder@ucbvax.Berkeley.EDU (Van Snyder) Subject: Re: Good for the Japanese In article <1991May30.120254.300@eagle.lerc.nasa.gov> ecaxron@venus.lerc.nasa.gov writes: >In article <1991May29.194342.11108@sequent.com>, szabo@sequent.com writes... > >>BTW, where were all the astronaut supporters screaming about >>"international agreements" when Solar-Polar got cut to feed the overgrown >>Shuttle budget? What a bunch of hypocrites. > >Solar-Polar. What was once known as the International Solar-Polar Mission >(ISPM), and is now known as Ulysses, was not cut. I figured you woulda >known that, though. Ulysses had to find a new ride to space after the >demise of the Shuttle/Centaur program. Which was based here at Lewis. And >which was killed because of the concerns *of the astronauts* in the wake of >the Challenger tragedy. So the astronaut supporters were right there. And >Ulysses never died, just got delayed. > >RG > >One hypocrite who knows the skinny. Only half the skinny. ISPM was to be a TWO spacecraft mission. When it got cut in half, ESA was pissed. -- vsnyder@jato.Jpl.Nasa.Gov ames!elroy!jato!vsnyder vsnyder@jato.uucp ------------------------------ Date: 30 May 91 18:45:30 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!sdd.hp.com!news.cs.indiana.edu!ariel.unm.edu!nmsu!charon!bwebber@ucbvax.Berkeley.EDU (Bill Webber) Subject: Re: 3D views from 2d data In article <49665@ut-emx.uucp> blake@ccwf.cc.utexas.edu (Blake Freeburg) writes: >I am interested in builing a 3D model of the starship enterprise out of >Star Trek: The Next Generation. I have good sequences of the ship passing >overhead, several side views, and it moving away, looking at the back of the >ship. I figure there is enough information in these to calculate 1/2 the >model, and since it is symmetric, I could then build the other half. > >Thanks to anyone who can help >Blake Freeburg I believe that very excellent models exist at any nearby hobby store. You would save many hours and much $$$$ by basing your model on one of these, IMHO. ------------------------------ Date: 30 May 91 19:28:36 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!hela!aws@ucbvax.Berkeley.EDU (Allen W. Sherzer) Subject: Re: Privatization In article <1991May30.151541.17548@sequent.com> szabo@sequent.com writes: >The answers will amaze your typical accountant. They sure amazed the >GAO, who raised NASA's Fred estimate by nearly a factor of 4. Although you point about the difficulty in tracking cost in government projects is well taken you made a mistake here. The GAO study is an estimate of the life cycle cost for Freedom. The NASA estimate is only design and construction costs. You should also bear in mind that the life cycle costs could be cut by a factor of two to four with suitable policy changes even after the station is built. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer | DETROIT: Where the weak are killed and eaten. | | aws@iti.org | | +---------------------------------------------------------------------------+ ------------------------------ Date: 30 May 91 16:14:01 GMT From: mcsun!ukc!strath-cs!prlhp1!hodsonb@uunet.uu.net (hodsonb) Subject: Re: Babies in Space Are you sure that a foetus in amniotic fluid is the same ? Whilst the foetus is floating it is still subject to gravity. For example a hollow spere full of air floating in a liquid ie displacing its own mass as an example. In a gravitational field a ball bearing will fall to the bottom of the spere, in space or zero gravity conditions the ball bearing will float. Therefore there is a distinct difference between a foetus in space and a foetus subject to gravity but floating. Once the foetus is born the situation obviously becomes even more dissimilar. Ben Hodson. (hodsonb@prl.philips.co.uk) ------------------------------ Date: 30 May 91 19:04:28 GMT From: wri!jlanter@uunet.uu.net (Jeff Lanter) Subject: NASA and Criticism peter@taronga.hackercorp.com (Peter da Silva) writes: >Who cares about Mars missions? Not I. That's the problem with the space >station... and all sorts of other NASA stuff: they have *no* idea what >they want to do. In fact, they don't even have the saving grace of having >a bad goal: they have no goals at all. That's a good point. However, I would have to imagine it's difficult for the planners at NASA to set big (or "good") goals for themselves, when their finantial backing can change like the shifting winds. The space station was, as it was initially envisioned, to be much larger and capable of a great deal more than current plans for Station Freedom. The establishment of larger short term goals is made impossible by the refusal of government to commit the $$$ to support a robust space program. My highly critical, earlier posting was in no way indended as an attack against NASA. They have always managed to achieve goals nothing short of miraculous with what money they had (Viking, Pinoeer, Voyager, Gallileo, SkyLab, the shuttle program). My beef lies much higher up in the government. When President Kennedy set a goal for NASA, he followed up by helping to insure the necessary funding was available. Despite what goals Reagan might have claimed to set for NASA, his followup in the funding department was less than adequate. Bush is proving to be even worse. I will always look to NASA to be the world leader in space technology and space exploration. I will also be looking with a very critical--if not downright cynical--eye to the members of congress to uphold the tradition of expansion and exploration. Of course, others will argue that federal moneys should be more appropriately be spent on social programs and problems here on Mother Earth. I can't argue that there is cause to answer those needs. However it is done, I certainly hope that congress will quit keeping such a choke hold on our space program. How did the President's words go...? "We choose to go to the moon and to do these other things, not because they are easy, but because they are hard. Because they will serve to measure the best among us." I'm sure I've slaughtered his words, but you get the idea.... -----Jeffrey ------------------------------ Date: 30 May 91 20:21:06 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!wuarchive!rex!rouge!pc.usl.edu!dlbres10@ucbvax.Berkeley.EDU (Phil) Subject: Re: Good for the Japanese Will writes: \In just few QUARTERS we started a project, partly worked on it and /restarted it again. The International community does'nt really \work this way. Japan thinks in terms of 50 years, Europe too, /about 50 years. America thinks in terms of now. This very minute. Actually, that's the way America's _Public Sector_ works. In spite of all the hubub going around about how government thinks in longer terms than private enterprise, the truth is government is divided between those who think in terms of (suprise!) two year terms (of office), one guy thinking four year terms, and about a hundred or so who think in six year terms. Private enterprise is thinking as long term as it can afford to, given what the government has done to all the investment capital with its massive debt (and also the Investment Discouragement, oops, Capital Gains Tax). Cooperation between Japan and America will probably decreace a lot after the cancellation, or even if Fred survives, at least in the group "Japanese Government/American Government." Japanese and Americans may continue to cooperate. I suspect in the future that international cooperation will be more "person to person" than "government to government." Phil Fraering || Usenet (?):dlbres10@pc.usl.edu || YellNet: 318/365-5418 Standard disclaimer, whatever a disclaimer is, applies. ''It hardly mattered now; it was, in fact, a fine and enviable madness, this delusion that all questions have answers, and nothing is beyond the reach of a strong left arm.`` - Larry Niven and Jerry Pournelle, _The Mote in God's Eye_ ------------------------------ Date: 31 May 91 05:14:16 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!ucselx!petunia!zeus!jgreen@ucbvax.Berkeley.EDU (James T. Green) Subject: Re: RE: USF, Inc. : Brought to you by the I would be interested in seeing a listing of the major members (not honorary types, such as the UN sec. general seems to be). I admit that I've not read throughly all the loooooong postings about this organization and such info might be there, but I think a posting of only the major movers and their credentials is in order. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * "I believe that this nation should commit itself to achieving * * the goal, before this decade is out, of landing a man on the * * Moon and returning him safely to the Earth." * * * * =============================================================== * * (-: James T. Green :-) * * Internet: jgreen@eros.calpoly.edu * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------------------------------ Date: 30 May 91 01:44:08 GMT From: csus.edu!wuarchive!zaphod.mps.ohio-state.edu!usc!chaph.usc.edu!sal-sun10.usc.edu!echeverr@ucdavis.ucdavis.edu (The Black Sheep) Subject: Re: Calculating delta-V In article <30042@hydra.gatech.EDU> ccoprmd@prism.gatech.EDU (Matthew DeLuca) writes: >In article <98181@lll-winken.LLNL.GOV> loren@tristan.llnl.gov (Loren Petrich) writes: > >> In "English" units, there is a unit of mass called the "pound" >>and a unit of force called a "pound". Their ratio is the acceleration >>of gravity, about 9.8 m/s^2. In this type of system, the ratio of >>force to mass rate is measured in seconds, when it is really a >>velocity, the effective exhaust velocity (EEV). > >Actually, the unit of mass in the English system is the slug. Oh? When was the last time you bought a 2-slug steak? :-) >At one g, the weight of this unit is 32.2 pounds. And, of course, the acceleration of gravity is 32.2 ft/sec^2... But let us move on... -- =============================================================================== Ron A Echeverri, | "God is a necessary invention. If there is The Black Sheep | no god, we would have to invent Him." BSAE 1994 Univ of So California | - Voltaire ------------------------------ Date: 31 May 91 23:54:12 GMT From: usc!zaphod.mps.ohio-state.edu!think.com!mintaka!ogicse!sequent!muncher.sequent.com!szabo@apple.com Subject: Re: Self-sustaining infrastructures In article <1991May31.034955.28620@agate.berkeley.edu> fcrary@earthquake.Berkeley.EDU (Frank Crary) writes: >For a 2-man station, of a soviet Mir-type, able to maintain/refuel/repair >50 satellites / year, the OMV to move the satellites around, and the logistical >support of this system... > >approximately $ 5,000 Million to develop/launch > 1,500 Million per year to support >This comes to $30 million per satellite repaired. This is stupendously wrong. * The best cost estimate for a four-man station is $120,000 million (GAO). It is unknown what Mir costs. A two man station requires the same life support, refuelling, etc. equipment R&D and would not, I think, cost significantly less than a 4-man job. * You don't show how either your development or operational cost figures are derived. * The number of satellites launched into any particular low earth orbit reachable by an OMV is less than 5/year, not 50/year. The number of those actually benefiting from refueling is probably no more than one per year; other satellites can be redesigned for optimum component/fuel lifetime balance for less than $30 million. * You didn't even bother to amortize the $5 billion. Over 30 years at 10%/year, this comes to $7,800 million per repair, about 6 times the cost of launching a brand new Hubble telescope, and 160 times the cost of making the largest launcher upgrade that could conceivably be needed (Titan 3 to Titan IV, c. $50 million) to add fuel to a large commercial satellite. To put it another way, we could launch 4 entire fleets of 77 commercial phone cell satellites for every one satellite your system could refuel. Even using the Shuttle ($900 million per launch) is far more economical than your scheme, although still far away from breakeven, which is amortization and operation costs of less than $50 million per year for LEO. -- Nick Szabo szabo@sequent.com "If you understand something the first time you see it, you probably knew it already. The more bewildered you are, the more successful the mission was." -- Ed Stone, Voyager space explorer ------------------------------ Date: 1 Jun 91 08:49:40 GMT From: cis.ohio-state.edu!pacific.mps.ohio-state.edu!linac!Firewall!ddsw1!zane@ucbvax.Berkeley.EDU (Sameer Parekh) Subject: Re: NASA and Criticism In article <6707@mcrware.UUCP> eric@mcrware.UUCP (Eric Miller) writes: [Good thoughts deleted] >Are these really such difficult issues for politicians and their constituents >to grasp??? > Yes. -- The Ravings of the Insane Maniac Sameer Parekh -- zane@ddsw1.MCS.COM ------------------------------ Date: 1 Jun 91 22:20:18 GMT From: haven.umd.edu!socrates.umd.edu!socrates!rockwell@louie.udel.edu (Raul Rockwell) Subject: Re: satellite refuelling Allen W. Sherzer: Again, it's like the early days of avation and the Kelly Act. Without it and the incentives it provided (multi-engines, advanced navigation and large cargo areas) we wouldn't have the aerospace industry we have today. Maybe. Then again, maybe not. It's kinda hard to second guess the past, especially when you're talking about the interaction between the government and private innovation. Or, if I phrase that differently, without the Kelly act (and other aviation related legislation and regulation) we might have a more advanced aerospace industry than what we currently have. But how could you verify something like this? Raul Rockwell ------------------------------ End of SPACE Digest V13 #651 *******************