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, 24 May 91 02:39:25 -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, 24 May 91 02:39:20 -0400 (EDT) Subject: SPACE Digest V13 #574 SPACE Digest Volume 13 : Issue 574 Today's Topics: The value of infrastructure (was: SPACE STATION FREEDOM WOUNDED) Alginquin RO Desaturation of the Reaction wheels on the Magellan Spacecraft space news from March 25 AW&ST Re: Mir Sweepstakes - Cancelled Re: SPACE STATION FREEDOM WOUNDED Re: SPACE STATION FREEDOM WOUNDED Re: NASA discovers ... dinosaurs' :-) (Forwarded) If no Freedom, what comes next? 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: 16 May 91 17:09:24 GMT From: emory!ox.com!hela!aws@gatech.edu (Allen W. Sherzer) Subject: The value of infrastructure (was: SPACE STATION FREEDOM WOUNDED) In article <9105161623.AA17143@gemini.arc.nasa.gov> greer%utdssa.dnet%utadnx@utspan.span.nasa.gov writes: >>its a pity the space science people don't support the creation of a better >>infrastructure. I can't think of anything which do more to promote science >>that the reduced costs we would see. >Huh? Please explain what you mean by all this. In the first place, it >isn't possible to do good space science from a manned space station. Some science could but I agree that most is better done in human tended free flyers. >In the second place, exactly what do you mean by reduced costs, especially >as relates to space science? Let's assume that we have a real infrastructure in LEO and on the moon. This includes fuel depots, orbital drydocks, and light manufacturing. Let's also assume that we where going to send a orbiter with an entry probe to, oh, let's say Jupiter. We'll name this probe after a well known early astonomer: Kepler. Because of our drydock we can do integration of the Kepler probe in space. This means we aren't nearly as constrained about the shape of the probe as other Jupiter bound probes have been. For example, Kepler won't need any complex error prone facilities to unfold things like antennas. Also remember that since these comploex deployment hardware isn't needed, we reduce weight and save money and (more important) design time. After the probe is integrated it is time to launch. Since we have a fuel dump supplied by extraterstrial materials the fuel costs about three orders of magnitude less. We can also have larger fuel tanks so the engines can burn longer. Kepler will not need complex orbital maneuvers which add risk and years to mission time like the other Jupiter bound probe. In addition, we now have upper stage engines which can fire for long periods of time and restart several times. Instead of buying brand new engines for Kepler we will use whatever is in stock. The bottom line to all this is that the incrimental cost of new space science missions goes way down if there is a proper infrastructure to support it. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer | Allen's tactics are too tricky to deal with | | aws@iti.org | -- Harel Barzilai | +---------------------------------------------------------------------------+ ------------------------------ Date: 16 May 91 21:03:56 GMT From: snorkelwacker.mit.edu!spool.mu.edu!mips!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!ephillip%magnus.acs.ohio-state.edu@bloom-beacon.mit.edu (Earl W Phillips) Subject: Alginquin RO I have been asked to forward the following message regarding the Algonquin RO for a friend who cannot send mail directly to the nwsgroup. Hope the info proves useful, it sure was to me! ***************************************************************** The rumors of the demise of ARO are exagerated. Just last year the Mark III VLBI system and the pointing system on the 46m antenna was upgraded in acooperative effort with NASA Goddard Space Flight Center's Crustal Dynamics Project. Last summer it was used in a series of geodetic VLBI sessions helping to establish the stability of the North American tectonic plate and establishing the locations of several GPS fiducial sites. The Canadians plan to continue its use as a VLBI base station. This may not be Astronomy, but it IS science. Since the antenna will remain operational, in the near future at least, it seems probable that radioastronomers with funding could get time on it. The major technical problem with using Algo is that it slews rather slowly. It IS 25 years old. Fortunately it is very sensitive compared to many antennas used for geodetic VLBI. This is a very nice when trying to make fringes to small antennas across long baselines. ***************************************************************** * | ====@==== ///////// * * ephillip@magnus.ircc.ohio-state.edu| ``________// * * | `------' * * -JR- | Space;........the final * * | frontier............... * ***************************************************************** ------------------------------ Date: 16 May 91 20:37:58 GMT From: ucivax!jarthur!elroy.jpl.nasa.gov!swrinde!zaphod.mps.ohio-state.edu!ub!ubvmsc.cc.buffalo.edu!v096my2q@ucbvax.Berkeley.EDU (Mark A Wieczorek) Subject: Desaturation of the Reaction wheels on the Magellan Spacecraft I've got a question for everyone out their. Why do the reaction wheels have to be desaturated on the magellan spacecraft? There are three reaction wheels which correspond to rotation in the x, y, and z directions. If the spacecraft was in a reference frame with no forces acting on it, desaturation would not be necessary. Does anyone know what kind of forces would be acting on the spacecraft that would put it in a non equilibrium situation? The only things that I can think of would be the following: 1) a frictional force coming from the upper atmosphere--how far does the venutian atmosphere extend anyways? 2) momentum from the solar wind 3) tidal forces acting on the spacecraft 4) irregularities of the gravitational field of the planet Any ideas or comments? Mark Wieczorek ------------------------------ Date: 17 May 91 01:42:53 GMT From: mintaka!olivea!samsung!cs.utexas.edu!news-server.csri.toronto.edu!utzoo!henry@bloom-beacon.mit.edu (Henry Spencer) Subject: space news from March 25 AW&ST [Light news week. Just as well, since I'm behind and need to catch up some.] Hiten becomes first spacecraft to do an aerobraking maneuver from deep space, making a pass over the north Pacific March 12th at 126km to reduce its velocity 1.77m/s. This may sound insignificant, but it lowered the apogee of Hiten's highly elliptical orbit by circa 1000km. Truly, although privately praising the Augustine report, is reported to be privately furious about one recommendation: tailoring the schedule for a Mars mission to the availability of funds. The report's phrase, "go as you pay", has been banned from NASA official documents. Truly reportedly thinks it is hard enough to get major programs funded with firm schedules, and volunteering to be flexible is an invitation to death by slow starvation. Administration working on rallying congressional support for the scaled- down space station. The emphasis now is on life sciences in support of future manned activity, rather than a general microgravity science facility. There are still some uncertainties about this role, notably the problem of where to put the much-moved centrifuge. Interestingly, there is now a possibility that Italy might add a small manned lab module, perhaps a life-sciences lab that could hold the centrifuge among other things. This is quite apart from Italy's ESA involvement; Italy wants to put some money into manned spaceflight as a bilateral US-Italy deal, and this is one possibility. Soviets marketing formerly-secret military store-and-forward data relay satellites as commercial comsat system. The 250kg low-orbit satellites go up six at a time aboard a Tsyklon booster; the intent of the Western consortium that is working with the Soviets is an operational constellation of 24 by 1995. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 16 May 91 00:56:47 PDT From: jim@pnet01.cts.com (Jim Bowery) To: crash!space+@andrew.cmu.edu Subject: Re: Mir Sweepstakes - Cancelled Gary W. Hoogeveen writes: > A Houston tv news show recently ran an update on the mir-men. > It seems that they have moved their entrepreneurial schemes to a > place less strict; they have gone to Nebraska. Evidently Nebraska laws > do not prohibit the promotion of sweepstakes, in contrast to the state > of Texas. > But to their credit, they have somehow arranged an official deal > with the soviets to fly the winner. It seems to be on the up and up, > according to a newspaper in the Soviet Union. Having talked to Jim Davidson this evening, I think I can safely say this is old news and is no longer valid. Space Travel is no longer advertising they can offer a trip with the Soviets and the business is not in operation. Indeed, they are being quite careful to avoid further advertising of a launch opportunity. ----------------------------------------------------------------------------- Jim Bowery 619/295-3164 The Coalition for PO Box 1981 Science and La Jolla, CA 92038 Commerce ----------------------------------------------------------------------------- ------------------------------ Date: 16 May 91 13:26:39 GMT From: swrinde!cs.utexas.edu!usc!samsung!news.cs.indiana.edu!widener!hela!aws@ucsd.edu (Allen W. Sherzer) Subject: Re: SPACE STATION FREEDOM WOUNDED In article yamauchi@cs.rochester.edu (Brian Yamauchi) writes: >Another question: is the money zeroed or just the program? The money. The NASA appropriation was reduced so something had to go. The house subcommittee decided to not vote money for Freedom. It works this way because first they decide how much to spend and then they decide how to spend it. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer | Allen's tactics are too tricky to deal with | | aws@iti.org | -- Harel Barzilai | +---------------------------------------------------------------------------+ ------------------------------ Date: 16 May 91 18:01:41 GMT From: elroy.jpl.nasa.gov!swrinde!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@handies.ucar.edu (Henry Spencer) Subject: Re: SPACE STATION FREEDOM WOUNDED In article <9105161623.AA17143@gemini.arc.nasa.gov> greer%utdssa.dnet%utadnx@utspan.span.nasa.gov writes: >... In the first place, it >isn't possible to do good space science from a manned space station. The principal investigators of the Skylab solar telescope would be surprised to hear that. What you *mean* is "my favorite projects can't be done from a manned space station". -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 15 May 91 13:47:04 GMT From: asuvax!mcdphx!qisoff!citek.UUCP!hbg6@handies.ucar.edu (John Schuch) Subject: Re: NASA discovers ... dinosaurs' :-) (Forwarded) > The team's findings agree with the work of other scientists >who have found unusual circular gravity and magnetic patterns and ^^^^^^^^^^^^^^^^ >quartz fractured by an impact, all suggesting a buried crater in the >Yucatan. OK, I'll ask. Can anyone explain (simply) what a circular gravity pattern is? John ------------------------------ Date: 17 May 91 00:30:09 GMT From: agate!tornado.Berkeley.EDU!gwh@ucbvax.Berkeley.EDU (George William Herbert) Subject: If no Freedom, what comes next? We should begin considering how we can fly an affordable station. Most of us would agree that an affordable station is a good thing. Let's work on designing one. I would suggest two initiatives: short and long term. Short term, look at what we can salvage from Freedom and other projects. Is there an alternative configuration that costs less? Long term: look at NDV as a launch platform. Paradigm shift; how do we design a station for $100/lb? (It's a rule of thumb that a space vehicle's final cost is usually about twice the launch cost; thus, if the NDV flies 10 tons to orbit for a $1 million pricetag, we want 10 ton $1 million modules...) George William Herbert gwh@ocf.berkeley.edu ------------------------------ End of SPACE Digest V13 #574 *******************