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 ; Thu, 16 May 91 02:26:08 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Thu, 16 May 91 02:26:02 -0400 (EDT) Subject: SPACE Digest V13 #560 SPACE Digest Volume 13 : Issue 560 Today's Topics: Re: Mir Sweepstakes - Cancelled NASA Headline News for 05/14/91 (Forwarded) Re: Why the space station? Re: Shuttle launches Re: New Subject--Solar Collectors/Antimatter Re: Shuttle launches Re: Saturn V and the ALS Re: New Subject--Solar Collectors/Antimatter Re: SPACE STATION FREEDOM WOUNDED 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: 14 May 91 17:35:29 GMT From: stanford.edu!leland.Stanford.EDU!pangea.Stanford.EDU!rick@decwrl.dec.com (Rick Ottolini) Subject: Re: Mir Sweepstakes - Cancelled Remember Heinlein's "Have Spacesuit, Will Travel" novel? The protagonist wins a spacesuit in a contest and accidently goes on a galactic adventure. This captures the excitement of the Mir contest. ------------------------------ Date: 14 May 91 17:33:04 GMT From: usenet@ames.arc.nasa.gov (Peter E. Yee) Subject: NASA Headline News for 05/14/91 (Forwarded) Headline News Internal Communications Branch (P-2) NASA Headquarters Tuesday, May 14, 1991 Audio Service: 202 / 755-1788 This is NASA Headline News for Tuesday, May 14, 1991 . . . NASA space flight managers yesterday selected May 22 as the target launch date for Columbia and the STS-40 Spacelab Life Sciences mission. The launch window opens on Wednesday, May 22, at 8:00 am and extends until 10:00 am EDT. Mission duration is expected to be just over nine days with a nominal end-of-mission landing at Edwards Air Force Base, Calif., on May 31 at 11:51 am EDT. Current activity at the Kennedy Space Center includes final orbiter closeout activities on Columbia and launch control complex preparations for the call to stations this weekend. * * * * * * * * * * * * * * * * NASA Administrator Richard Truly yesterday announced the creation of a new Systems Analysis and Concepts Office at NASA Headquarters. James D. Bain was also named as director of the new office, which will provide independent and non-advocate decision support to the Administrator. The new office will focus on policy alternatives and on the conceptual and formulative stages of new programs. It is another step in NASA's implementation of the recommendations of the Advisory Committee on the Future of the U.S. Space Program, headed by Norman Augustine. * * * * * * * * * * * * * * * * Goddard Space Flight Center reports that the calibration of instruments aboard the Gamma Ray Observatory is going well and will conclude tomorrow. On Thursday, May 16, the GRO science operations will begin. Phase 1 of the science observation is a full-sky survey of gamma ray sources which is expected to take 15 months to complete. All spacecraft systems are reported in nominal condition. * * * * * * * * * * * * * * * * The Tracking and Data Relay Satellite-E is currently undergoing spacecraft fitness checks at Kennedy Space Center. The astronaut crew payload inspection will occur next Monday and a spacecraft end-to-end test will begin on May 29. Presently, KSC expects to install the TDRS with inertial upper stage into Atlantis' payload bay by the end of June. Atlantis' STS-43 mission to deploy the TDRS-E spacecraft is the next mission after Columbia's STS-40 flight. * * * * * * * * * * * * * * * * NASA-816, the Convair F-106B which Langley Research Center made famous as its "lightning strike" vehicle, was retired recently and will be transferred to the new Virginia Air and Space Center in Hampton. The F- 106 has for the past 12 years flown vortex research and storm hazard missions for Langley, and in that time has been struck more than 700 times by lightning while aloft. It was used by Lewis Research Center in the 70s as a supersonic transport research plane and prior to that flew nine years as an Air Force research plane. It was the last F-106 flying and was the second Consolidated Vultee aircraft to use the Langley- designed "area rule"fuselage. The F-102, Convair's predecessor to the 106, was the first to use the Langley Coke-bottle shape, which made level- flight supersonic speed practical. * * * * * * * * * * * * * * * * Marshall Space Flight Center reports that its three Spacemobile lecturers last month visited 31 schools in their region reaching a student audience of over 24,000. The center also provided educational support for Kentucky Space Week, a week-long state-sponsored program modeled after the very successful Tennessee Space Week. Marshall also reports that their online educational database - Spacelink - now has over 5,600 registered users, 2,300 of whom indicate they are teachers or students. The electronic system received a record 7,500 calls during April, which Marshall attributes to interest in the STS-39 mission. Stennis Space Center reports that its Community Leader Briefing was successful with more than 70 community leaders in the Mississippi Gulf Coast and Louisiana Delta region attending. Stennis followed the briefing with a reception and the opportunity to view a space shuttle main engine being test fired. The center also reports that their Early Education Monday program was presented to 163 kindergartners from five local elementary and day care facilities, including Stennis' own. Here's the broadcast schedule for Public Affairs events on NASA Select TV. Note that all events and times may change without notice, and that all times listed are Eastern. Tuesday, 5/14/91 10:00 am Begin coverage for NOAA-D launch, from Vandenberg Air Force Base. Launch is set for 11:52 am EDT. LIVE 2:30 pm STS-40 mission overview press briefing with lead flight director Al Pennington, from Johnson Space Center. LIVE 3:30 pm STS-40 astronaut crew press briefing with Bryan O'Connor, commander; Sid Gutierrez, pilot; Tammy Jernigan, Rhea Seddon and Jim Bagian, mission specialists; and Drew Gaffney and Millie Hughes-Fulford, payload specialists, from JSC. LIVE Wednesday, 5/15/91 10:00 am STS-40 general science and mission management overview press briefings with Dr. Arnauld Nicogossian, Dan Womac and Dr. Howard Schneider, from JSC. LIVE 11:00 am STS-40 metabolic investigations briefing with Dr. Carolyn Leach, from JSC. LIVE 11:30 am STS-40 neurovestibular investigations briefing with Dr. Laurance Young, from JSC. LIVE 12:00 pm STS-40 cardiovascular investigations briefing with Dr. Leon Farhi, from JSC. LIVE 12:30 pm STS-40 cardiopulmonary investigations briefing with Dr. Harold Guy, from JSC. LIVE 1:15 pm Magellan-at-Venus final status report, from Jet Propulsion Laboratory. Magellan will have completed one full mapping cycle of the planet. LIVE 2:00 pm STS-40 musculoskeletal investigations briefing with Dr. Kenneth Baldwin, from JSC. LIVE 2:30 pm STS-40 briefing on other disciplines and tests with Dr. Gary Jahns, from JSC. LIVE 3:30 pm STS-40 Get-Away-Special cannister briefings from Goddard Space Flight Center. LIVE This report is filed daily at noon, Monday through Friday. It is a service of NASA's Office of Public Affairs. The contact is Charles Redmond, 202/453-8425 or CREDMOND on NASAmail. NASA Select TV is carried on GE Satcom F2R, transponder 13, C-Band, 72 degrees West Longitude, transponder frequency is 3960 megaHertz, audio is offset 6.8 MHz, polarization is vertical. ------------------------------ Date: 15 May 91 04:32:05 GMT From: mintaka!ogicse!sequent!muncher.sequent.com!szabo@bloom-beacon.mit.edu Subject: Re: Why the space station? In article dlbres10@pc.usl.edu (Fraering Philip) writes: >Mars will not be as easy to quantify with an Apollo-style sampling >as the moon was. Anyway, even with HLV, the scale I just described >would have to be assembled in space or the mission foregone. Watch out, another solution in search of a problem is rearing its ugly head... Returning Martian polar samples wouldn't require any sort of assembly. You would land a small drilling rig on the pole, bring up a nice long thin core, take pictures of it as it came up, and chop pieces out of it at intervals for on-site analysis or return to earth via rendesvous and sample transfer in Martian orbit. The lander/drilling rig is all one piece, the orbiter is a separate peice. There is no benefit from assembly; forcing assembly on the mission could severely handicap the functions. -- 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: 15 May 91 15:54:05 GMT From: psuvm!esoc!tnedderh@psuvax1.cs.psu.edu (Thorsten Nedderhut) Subject: Re: Shuttle launches Think of the little Pegasus on B-52 and its altitude range. Try to compare it with the STS and the SCA. Any questions? ------------------------------ Date: 15 May 91 23:13:45 GMT From: agate!bionet!uwm.edu!cs.utexas.edu!news-server.csri.toronto.edu!utzoo!henry@ucbvax.Berkeley.EDU (Henry Spencer) Subject: Re: New Subject--Solar Collectors/Antimatter In article <12321@mentor.cc.purdue.edu> f3w@mentor.cc.purdue.edu (Mark Gellis) writes: > 1) Given a solar cell that will produce 10 kilowatts in Earth orbit, >would the same cell (i.e., the same mass of finished product) produce more >power if it was moved to Venus orbit, where it would be getting more than >twice as much energy from sunlight? ... Power output is proportional to available light, but there are limits. Eventually the cell will overheat. Exactly where trouble begins is a function of the cell technology. There may also be some nonlinearities in the response at high light levels, I'm not sure. If you're in the bulk solar power business, it is *probably* better to use mirrors and turbogenerators. Mirrors are lighter and easier to make in large areas than solar cells, and turbogenerators have 2-3 times the efficiency of solar cells. They do result in more complex systems, but in large sizes that is probably worthwhile, unless there is some special constraint operating. >... Could we build solar power stations, say, in Mercury orbit, where >we would be getting more than six times the sunlight we get in Earth orbit? If you are doing things with solar power on a large scale, doing it near Mercury is probably better than doing it near Earth. It will take slightly different system designs, but it should be practical. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 14 May 91 14:10:44 GMT From: aio!vf.jsc.nasa.gov!kent@eos.arc.nasa.gov Subject: Re: Shuttle launches In article <1991May12.034146.19113@ncsu.edu>, dfrobins@eos.ncsu.edu (DAVID F ROBINSON) writes: > Was there ever any consideration for launching the shuttle off of the carrier > aircraft. It could have been carried to 40-50 kft and after it cleared the > aircraft it could ignite its engines. Wouldn't this have greatly reduced > the fuel mass required? With this scenario the shuttle also could have glided > back in case of any engine problems. > The Shuttle Carrier Aircraft can carry the Shuttle. It cannot, however, carry the Shuttle and it fully fueled External Tank! Remember the Shuttle main engines get ALL of their hydrogen and O2 from the tank. Even if it could carry the External Tank, The shuttle main engines generate a combined thrust of about 450,000 pounds. The Shuttle stack ( Shuttle, External Tank, and SRB's) weigh about 4.6 million pounds at liftoff. Each SRB has a little over 3.2 million pounds of thrust. SRB's thrust + the Shuttle main engines = about 7 million pounds of thrust at liftoff. Without SRB's the shuttle will go nowhere. The Shuttle carrier aircraft (747) just cannot carry that weight. -- Mike Kent - Lockheed Engineering and Sciences Company at NASA JSC 2400 NASA Rd One, Houston, TX 77058 (713) 483-3791 KENT@vf.jsc.nasa.gov ------------------------------ Date: 15 May 91 07:41:00 GMT From: swrinde!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!wa4mei!ke4zv!gary@ucsd.edu (Gary Coffman) Subject: Re: Saturn V and the ALS In article <1991May8.015849.2874@murdoch.acc.Virginia.EDU> gsh7w@astsun9.astro.Virginia.EDU (Greg Hennessy) writes: >"You screwed up the last time, why should I trust you know?" > >and you say: > >"ALS is not the shuttle." > >then you lose. I don't have to prove that ALS won't work. You have to >prove it will, at least before you expect to have large sums of money >given to it. Since the track record so far is an expensive launch >system that does not meet promises, it is nearly *impossible* to trust >you again. NASA's track record doesn't begin with the Shuttle. Most of NASA's programs have been wildly successful. A few have not. Even for the shuttle, most of the systems perform as planned. Bad choices, driven primarily by budget pressure, dictated the present SRBs, tiles over aluminum rather than titanium, and other tradeoffs that have made the shuttle unreliable and difficult to maintain. When you look at NASA's track record from X15 flights through Apollo, Voyager, Viking, etc, holding the shuttle alone over their heads as representative of their track record is unfair. ALS is supposed to capitalize on the experience drawn from the mistakes made with the shuttle. NASA more than anyone knows the faults of the shuttle. NASA more than anyone doesn't want to make those same mistakes again. NASA also has a long proven track record of things that work. They can draw on that experience as well. To succeed, NASA must constantly point to the shuttle, and the political and technical decisions that made it what it is. NASA must insist that they be allowed to build a good system, or no system at all. Whether NASA's current leadership has this courage is the major question about the ALS or any other system in NASA's future. The current debacle with Fred hints that they may not. To be fair, it must be realized that the current NASA leadership took power after major commitments to Fred were already made, including foreign commitments. With ALS they will have a clean sheet of paper and a chance to do it right. Gary ------------------------------ Date: 15 May 91 15:41:54 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!menudo.uh.edu!jetson.uh.edu!mecewd@tut.cis.ohio-state.edu Subject: Re: New Subject--Solar Collectors/Antimatter In article <12321@mentor.cc.purdue.edu>, f3w@mentor.cc.purdue.edu (Mark Gellis) writes: > My question regards the efficiency of solar collectors. Now, obviously, > technology will change and improve during the next few centuries, but based > on what we know today about such solar power cells... > > 1) Given a solar cell that will produce 10 kilowatts in Earth orbit, > would the same cell (i.e., the same mass of finished product) produce more > power if it was moved to Venus orbit, where it would be getting more than > twice as much energy from sunlight?... > > 2) If you can get more energy from solar cells by moving them closer > to a star, what is the limit?... There are solar cells manufactured today which are designed to work with concentrators, and can handle 100 suns (i.e., equivalent radiation at Earth, 1 sun = about 1400 W/m^2, as I recall) or more. They are more expensive than conventional cells. So the answer is yes, as you move closer to the sun, you can get more energy per square meter of solar array. However, because not all the solar flux is converted to electricity, the rest is absorbed by the solar array as heat. The only way to get rid of this heat is through radiation. The total heat you can get rid of this way is a function of the array area and the maximum temp. the solar panels can take (roughly, as Area*Temp.^4). Even if 99% of the solar flux is converted to electricity (current cells can get 15-30%), the 1% left over as heat HAS to be dealt with. Based on current technology, a solar power station close to Mercury as you describe is feasible. But much closer than that, the thermal limit starts to be a problem, probably long before the concentration limit becomes an issue. This also limits how close you can bring a solar sail to the sun, though solar sails can reflect away much of the solar flux to begin with. So much for the short course on radiation heat transfer. Hope this answers your question. Christian L. Struble Department of Mechanical Engineering mecewd@jetson.uh.edu University of Houston -------------------------------------------------------------------------- ------------------------------ Date: 16 May 91 03:05:03 GMT From: iggy.GW.Vitalink.COM!widener!hela!aws@lll-winken.llnl.gov (Allen W. Sherzer) Subject: Re: SPACE STATION FREEDOM WOUNDED In article yamauchi@cs.rochester.edu (Brian Yamauchi) writes: >My question is how much of this money will actually go to space >science and unmanned space exploration. I'd rather have a lot of >Mariner Mark IIs, planetary rovers, and microprobes than Freedom, but >I'd rather have Freedom than nothing... The real problem is that NASA is funded from the same bucket of money as housing projects and vetrans funds. People try very hard to get on this committee so they can shovel HUD money into their districts. From the point of view of many of them NASA just hurts this process. The upshot of this is that in the short run this money will go to space science but in the long run they will eventually fall prey to the same forces we see at work today. The real problem of course is our socialist aerospace system. We spend all we need to to have a good space science program AND a good exploration program. We just don't spend our moeny very wisely. The House action today (and if the Senate supports it) is IMHO a step in the right direction. We need to exploit this and turn it into an advantage. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer | Allen's tactics are too tricky to deal with | | aws@iti.org | -- Harel Barzilai | +---------------------------------------------------------------------------+ ------------------------------ End of SPACE Digest V13 #560 *******************