Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.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 ; Wed, 9 Jan 1991 01:42:37 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 9 Jan 1991 01:41:54 -0500 (EST) Subject: SPACE Digest V13 #028 SPACE Digest Volume 13 : Issue 28 Today's Topics: NASA Headline News for 01/04/91 (Forwarded) room avail to see eclipse Re: Chiron and asteroid belts Building a sundial, position of the sun Re: Bussard ramjet question Satellite description Re: Interstellar Light Sails Re: Interplanetary travel Re: Interstellar Travel 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 ---------------------------------------------------------------------- Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 4 Jan 91 22:22:24 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Organization: NASA Ames Research Center, Moffett Field, CA Subject: NASA Headline News for 01/04/91 (Forwarded) Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu Headline News Internal Communications Branch (P-2) NASA Headquarters Friday, January 4, 1991 Audio Service: 202 / 755-1788 This is NASA Headline News for Friday, January 4, 1991 NASA has announced that it would jointly develop a spacecraft with the European Space Agency to study the planet Saturn, its moons, rings, atmosphere and magnetosphere. The formal agreement was recently signed by Administrator Truly and ESA Director-General Jean-Marie Luton. Named after the 17th century astronomer, Jean Dominique Cassini, the probe will explore the Saturnian system with a planetary orbiter provided by NASA and an ESA-provided Titan moon-orbiter. The Saturnian mission is expected to last for at least eleven years, seven of which will be required for the journey to the outer planet. Enroute, Cassini will make asteroid observations and a Jupiter fly-by. NASA expects to launch the Cassini spacecraft aboard a Titan IV/Centaur booster in April 1996. * * * * * * * * * * * * * * Artificial auroras may be created in January night skies when NASA conducts experiments releasing metallic vapors from the Combined Release and Radiation Effects Satellite. The joint NASA/USAF project seeks to understand the processes which cause auroras by using artificial charged-particle clouds to induce them. The release of the barium and lithium vapors into the Earth's magnetosphere will have no adverse environmental effect, and is expected to be visible in the western hemisphere. Scientists are studying auroral effects, which not only produce brilliant natural displays, but affect high frequency communications, power systems, and sensitive terrestrial and space instruments. * * * * * * * * * * * * * * * * Kennedy Space Center workers installed the Forward Reaction Control System on the Space Shuttle Discovery last night, and an interface test of the system is planned for tomorrow. Discovery is being prepared for rollover to the Vehicle Assembly Building at the end of this month. The orbiter Atlantis is powered up today for routine tests, and new general purpose computers are being installed. In the VAB, Columbia's tile system is being waterproofed. Technicians removed sleep stations from the orbiter crew cabin yesterday. Stacking of the STS-37 (Atlantis) Solid Rocket Boosters continues, and the new 17-inch liquid hydrogen disconnect is being positioned on the External tank. (No scheduled television programming through Monday) This report is filed daily, Monday through Friday, at 12:00 pm, EST. It is a service of Internal Communications Branch at NASA Headquarters. Contact: CREDMOND on NASAmail or at 202/453-8425. NASA Select TV: Satcom F2R, Transponder 13, C-Band, 72 degrees West Longitude, Audio 6.8, Frequency 3960 MHz. ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 4 Jan 91 18:29:56 GMT From: uoft02.utoledo.edu!desire.wright.edu!duetrecht@tut.cis.ohio-state.edu Organization: University Computing Services, Wright State University Subject: room avail to see eclipse Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu Going to the eclipse in Mexico this July and need someplace to stay? I have an extra space or two to fill in my hotel room in Puerto Vallarta starting on the night of Thursday 7/4/91 and ending on the night of Friday 7/12/91. If interested email to this address or call 1-513-435-4558 between 8:00am and 05:00pm EST and just ask for Jack Frillman. ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 2 Jan 91 02:46:22 GMT From: ogicse!intelhf!agora!trifid@uunet.uu.net (Edward Fitzgerald) Organization: Open Communications Forum Subject: Re: Chiron and asteroid belts References: <1990Dec31.162330.26603@athena.mit.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu This reminds me...Members of a local BBS asked a question I am also interested in. Are there any plans to have the Hubble look for/at any of our asteroids? It would seem like the perfect device to finally get a good look at them. Suze Hammond ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 4 Jan 91 19:05:01 GMT From: njin!njitgw!hertz.njit.edu!ken@rutgers.edu (ken ng cccc) Organization: New Jersey Institute of Technology, Newark, N.J. Subject: Building a sundial, position of the sun References: <1990Dec28.125421@axion.bt.co.uk>, <1429@mpirbn.mpifr-bonn.mpg.de> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu Please pardon the cross-posting, I'm not sure which newsgroup this request belongs to. I have recently moved into a new office with a southern view. I would like to put a small mirrow on the window to reflect the sun up at the ceiling where I will have placed a sundial calbrated by time of day and day of year. My problem is, is there any way of doing this besides marking it every day of the year? Given the time, my longitude, lattitude, and day of year, does anyone know a way to compute where the sun will be in the sky? Has anyone else tried something this nutty? ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Dec 90 22:49:18 GMT From: swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!censor!geac!torsqnt!lethe!telly!moore!eastern!egsgate!Maury.Markowitz@ucsd.edu (Maury Markowitz) Organization: EGS/Philo BBS Gateway, Toronto (416) 286-6191 Subject: Re: Bussard ramjet question Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu >>OK, I was thinking about Bussard ramjets the other day (after reading >>entirely too much science fiction) and got to wondering: How do >>you decelerate with a Bussard ramjet? ... >You're going to have to decelerate the incoming gas essentially to >a halt to hang onto it long enough to fuse it, unless you've got a >truly remarkably rapid fusion reaction going somehow. That being >the case, there is no reason why you can't point the exhaust jet >and the ramscoop in the same direction rather than in opposite >directions. The more common suggestion as seen in JBIS is to hang a large "shield" behind the craft, turn off the fusion, and let the incoming particle stream reflect off the shield. An energy-limited system has been investigated in several papers, try... G. L. Matloff and A. J. Fennelly, "Interstellar Applications and Limitations of Several Electrostatic/Electromagnetic Ion Collection Techniques", JBIS 30 (1977):213-222 N. H. Langston, "The Erosion of Interstellar Drag Screens", JBIS 26 (1973): 481-484 C. Powell, "Flight Dynamics of the Ram-Augmented Interstellar Rocket", JBIS 28 (1975):553-562 A. R. Martin, "The Effects of Drag on Relativistic Spacefight", JBIS 25 (1972):643-652 Hope that helps. Maury -- EGSGate Fidonet Gateway, Toronto (egsgate.fidonet.org) ...!{uunet, moore, lsuc}!eastern!egsgate ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: Fri, 4 Jan 91 13:39:19 PST From: trop@hls.com (Troy T. Pummill) To: space+@andrew.cmu.edu Subject: Satellite description Netlanders, Now that I have copies of orbital data from T.S. Kelso and T. Molzcan, where can I find a file that describes the different satellites and their functions..... thanks...troy (Troy) ----------------------------------------------------------------------------- | Troy T. Pummill | trop@hls.com | | Sr. Technical Instructor | ...uunet!lanslide.hls.com!trop | | Hughes LAN Systems | 1225 Charleston Rd., Silicon Gulch | | Mountain View, CA 94043 | The preceding drivel is entirely my own! | ----------------------------------------------------------------------------- ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 4 Jan 91 22:40:57 GMT From: zephyr.ens.tek.com!tektronix!sequent!crg5!szabo@beaver.cs.washington.edu (Nick Szabo) Organization: Sequent Computer Systems, Inc Subject: Re: Interstellar Light Sails References: <1990Dec29.212153.20748@cunixf.cc.columbia.edu>, <1990Dec30.004107.7363@zoo.toronto.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <1990Dec30.004107.7363@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >[Forward's] lightsails in particular showed up in serious papers before >he used them in his fiction. If you can build the laser system >on the necessary colossal scale, laser sails are workable. What is the spread of a laser over interstellar, or even interplanetary distances? Last I heard from the deep-space laser communications people, there is large dispersion over even interplanetary distances (alas I don't have figures handy). Transmitting power around the solar system via laser could be quite useful to future space industry, if it is feasible. -- Nick Szabo szabo@sequent.com "If you want oil, drill lots of wells" -- J. Paul Getty The above opinions are my own and not related to those of any organization I may be affiliated with. ------------------------------ Date: Fri, 4 Jan 91 21:14:42 EST From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Re: Interplanetary travel >Date: 24 Dec 90 20:40:16 GMT >From: cs.utexas.edu!news-server.csri.toronto.edu!utgpu!cunews!cognos!geovision!gd@tut.cis.ohio-state.edu (Gord Deinstadt) >Organization: GeoVision Corp., Ottawa, Ontario >Subject: Re: Interstellar travel >Fusion engines are just the thing for travelling about in the solar >system. Since the ideal reaction mass is 4 times the (payload+ ------------------------------------------------ >structure) mass, there is no point in having a higher-density fuel. --------------- >You just have to carry more reaction mass to compensate for the >reduction in mass of the fuel. Consequently, for efficient (minimum- >energy) operation, fusion is just as good as antimatter, provided >the fusion reactor can be made light enough. >Gord Deinstadt gdeinstadt@geovision.UUCP I don't understand why that should be considered an ideal ratio. By the classic equations, this should allow a total change in velocity of about 1.6 times the exhaust velocity, but why is that a particularly good number? John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 5 Jan 91 01:33:43 GMT From: mindcraft.com!ronnie@ames.arc.nasa.gov (Ronnie Kon) Subject: Re: Interstellar Travel In article <1991Jan4.170012.4367@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >In article <9101041605.AA15306@hermes.intel.com> thamilton@ch3.intel.com (Tony Hamilton, WF1-81, x48142) writes: > >given that the energy requirements go as the square of velocity. (Energy >is the dominant problem of starflight.) It's also the dominant problem of interstellar communications. Even with a really bitching Buck-Rogers 0-degree-spread laser, it's going to be awfully hard to punch a beam all the way back to Earth. We're having enough trouble just receiving Voyager's transmissions, and it's not even out of the solar system. Perhaps it could go into a parking orbit around the star (doing a hell of a decelleration from .2C to orbital velocity) and absorb solar energy to power it. The beam would then, however, have to be separated from the overwhelming energy from the very close, and very bright, star. Perhaps it can do a flyby, and do a 180 turn through the gravity well, and return to us. Probably about as likely as an interplanetary mission within the next couple of centuries. Pity. Ronnie -- ------------------------------------------------------------------------------- Ronnie B. Kon | "I don't know about your brain, but kon@groundfog.stanford.edu | mine is really bossy." ...!{decwrl,ames}!mindcrf!ronnie | -- Laurie Anderson ------------------------------ End of SPACE Digest V13 #028 *******************