Date: Wed, 5 May 93 05:25:01 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #519 To: Space Digest Readers Precedence: bulk Space Digest Wed, 5 May 93 Volume 16 : Issue 519 Today's Topics: Space FAQ 02/15 - Network Resources Space FAQ 04/15 - Calculations Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: 3 May 1993 12:14:28 -0400 From: Jon Leech Subject: Space FAQ 02/15 - Network Resources Newsgroups: sci.astro,sci.space,sci.answers,news.answers Archive-name: space/net Last-modified: $Date: 93/05/03 12:08:09 $ NETWORK RESOURCES OVERVIEW You may be reading this document on any one of an amazing variety of computers, so much of the material below may not apply to you. In general, however, systems connected to 'the net' fall in one of three categories: Internet, Usenet, or BITNET. Electronic mail may be sent between these networks, and other resources available on one of these networks are sometimes accessible from other networks by email sent to special 'servers'. The space and astronomy discussion groups actually are composed of several mechanisms with (mostly) transparent connections between them. One mechanism is the mailing list, in which mail is sent to a central distribution point which relays it to all recipients of the list. In addition to the general lists for space (called SPACE Digest for Internet users, and SPACE on BITNET), there are a number of more specialized mailing lists described below. A second mechanism is Usenet 'netnews'. This is somewhat like a bulletin board operating on each system which is a part of the net. Netnews separates contributions into hundreds of different categories based on a 'group name'. The groups dealing most closely with space topics are called 'sci.space.news', 'sci.space', 'sci.space.shuttle', 'sci.astro', and 'talk.politics.space'. Contributors 'post' submissions (called 'articles' in netnews terminology) on their local machine, which sends it to other nearby machines. Similarly, articles sent from nearby machines are stored locally and may be forwarded to other systems, so that an article is posted locally and eventually reaches all the Usenet sites interested in receiving the news group to which the article was posted. Gateway machines redirect the Usenet sci.space group into Internet and BITNET mailing lists and vice versa; the other Usenet groups are not accessible as mailing lists. If you can receive netnews, its more flexible interface and access to a wider range of material usually make it the preferred option. MAILING LISTS SPACE Digest is the main Internet list, and is now being run by the International Space University (in only its second change of management in over a decade). Email space-request@isu.isunet.edu (message body should be in the format 'subscribe space John Public') to join. Note that the moderated SPACE Magazine list is defunct at present for lack of a moderator. Old copies of SPACE Digest since its inception in 1981 are available by anonymous FTP. Retrieve julius.cs.qub.ac.uk:pub/SpaceDigestArchive/README for further details. Elements is a moderated list for fast distribution of Space Shuttle Keplerian Elements before and during Shuttle flights. NASA two line elements are sent out on the list from Dr. Kelso, JSC, and other sources as they are released. Email to elements-request@telesoft.com to join. GPS Digest is a moderated list for discussion of the Global Positioning System and other satellite navigation positioning systems. Email to gps-request@esseye.si.com to join. Space-investors is a list for information relevant to investing in space-related companies. Email Vincent Cate (vac@cs.cmu.edu) to join. Space-tech is a list for more technical discussion of space topics; discussion has included esoteric propulsion technologies, asteroid capture, starflight, orbital debris removal, etc. Email to space-tech-request@cs.cmu.edu to join. Archives of old digests and selected excerpts are available by anonymous FTP from gs80.sp.cs.cmu.edu (128.2.205.90) in /usr/anon/public/space-tech, or by email to space-tech-request if you don't have FTP access. SEDS-L is a BITNET list for members of Students for the Exploration and Development of Space and other interested parties. Email LISTSERV@TAMVM1.BITNET with a message saying "SUBSCRIBE SEDS-L your name". Email saying "INDEX SEDS-L" to list the archive contents. SEDSNEWS is a BITNET list for news items, press releases, shuttle status reports, and the like. This duplicates material which is also found in Space Digest, sci.space, sci.space.shuttle, and sci.astro. Email LISTSERV@TAMVM1.BITNET saying "SUBSCRIBE SEDSNEWS your name" to join. Email saying "INDEX SEDSNEWS" to list the archive contents. Ron Baalke (baalke@kelvin.jpl.nasa.gov) runs a mailing list which carries the contents of the sci.space.news Usenet group. Email him to join the list. As a general note, please mail to the *request* address to get off a mailing list. SPACE Digest, for example, relays many inappropriate 'please remove me from this list' messages which are sent to the list address rather than the request address. PERIODICALLY UPDATED INFORMATION In addition to this FAQ list, a broad variety of topical information is posted to the net (unless otherwise noted, in the new group sci.space.news created for this purpose). Please remember that the individuals posting this information are performing a service for all net readers, and don't take up their time with frivolous requests. ACRONYMS Garrett Wollman (wollman@UVM.EDU) posts an acronym list around the first of each month. ASTRO-FTP LIST Veikko Makela (veikko.makela@helsinki.fi) posts a monthly list of anonymous FTP servers containing astronomy and space related material to sci.space and sci.astro. AVIATION WEEK Henry Spencer (henry@zoo.toronto.edu) posts summaries of space-related stories in the weekly _Aviation Week and Space Technology_. BUYING TELESCOPES Ronnie Kon (ronnie@cisco.com) posts a guide to buying telescopes to sci.astro. ELECTRONIC JOURNAL OF THE ASA Don Barry (don@chara.gsu.edu) posts the monthly Electronic Journal of the Astronomical Society of the Atlantic to sci.astro. FLIGHT INTERNATIONAL Swaraj Jeyasingh (sjeyasin@axion.bt.co.uk) posts summaries of space-related news from _Flight International_. This focuses more on non-US space activities than Aviation Week. LARGE ASTRONOMICAL PROJECTS Robert Bunge (rbunge@access.digex.com) posts a list describing many "Large Telescope Projects Either Being Considered or in the Works" to sci.astro. NASA HEADLINE NEWS & SHUTTLE REPORTS Peter Yee (yee@ames.arc.nasa.gov) posts a variety of NASA material, including NASA Headline News (with the schedule for NASA SELECT), shuttle payload briefings and flight manifests, and KSC shuttle status reports. For Usenet users, much of this material appears in the group sci.space.shuttle. NASA UPDATES Ron Baalke (baalke@kelvin.jpl.nasa.gov) posts frequent updates from JPL, Ames, and other centers on the Ulysses, Gailileo, Pioneer, Magellan, Landsat, and other missions. ORBITAL ELEMENT SETS TS Kelso (tkelso@blackbird.afit.af.mil) posts orbital elements from NASA Prediction Bulletins. Mike Rose (mrose@stsci.edu) posts orbital elements for the Hubble Space Telescope to sci.astro. Jost Jahn (j.jahn@abbs.hanse.de) posts ephemerides for asteroids, comets, conjunctions, and encounters to sci.astro. SATELLITE LAUNCHES Richard Langley (lang@unb.ca) posts SPACEWARN Bulletin, which describes recent launch/orbital decay information and satellites which are useful for scientific activities. Recent bulletins are available by anonymous FTP from nssdca.gsfc.nasa.gov in ANON_DIR:[000000.ACTIVE.SPX]. SHUTTLE MANIFEST Ken Hollis (gandalf@pro-electric.cts.com) posts a compressed version of the Space Shuttle launch manifest to sci.space.shuttle. This includes dates, times, payloads, and information on how to see launches and landings. SOLAR ACTIVITY Cary Oler (oler@hg.uleth.ca) posts Solar Terrestrial reports (describing solar activity and its effect on the Earth) to sci.space. The report is issued in part from data released by the Space Enviroment Services Center, Boulder Colorado. The intro document needed to understand these reports is available by anonymous FTP from solar.stanford.edu (36.10.0.4) in pub/understanding_solar_terrestrial_reports. nic.funet.fi (128.214.6.100) also has this document in /pub/misc/rec.radio.shortwave/solarreports and is an archive site for the reports (please note this site is in Europe, and the connection to the US is only 56KB). A new primary archive site, xi.uleth.ca (142.66.3.29), has recently been established and will be actively supported. SOVIET SPACE ACTIVITIES Glenn Chapman (glennc@cs.sfu.ca) posts summaries of Soviet space activities. SPACE ACTIVIST NEWSLETTER Allen Sherzer (aws@iti.org) posts a newsletter, "One Small Step for a Space Activist," to talk.politics.space. It describes current legislative activity affecting NASA and commercial space activities. SPACE EVENTS CALENDAR Ron Baalke (baalke@kelvin.jpl.nasa.gov) posts a calendar including anniversaries, conferences, launch dates, meteor showers and eclipses, and other space-related events. SPACE NEWS John Magliacane (kd2bd@ka2qhd.UUCP) posts "SpaceNews" (covering AMSATs, NOAA and other weather satellites, and other ham information) to rec.radio.amateur.misc and sci.space. SPACE REPORT Jonathan McDowell (mcdowell@cfa.harvard.edu) posts "Jonathan's Space Report" covering launches, landings, reentries, status reports, satellite activities, etc. TOWARD 2001 Bev Freed (freed@nss.fidonet.org) posts "Toward 2001", a weekly global news summary reprinted from _Space Calendar_ magazine. WARNING ABOUT NON-PUBLIC NETWORKS (Included at the suggestion of Eugene Miya, who wrote the item) NASA has an internal system of unclassified electronic mail and bulletin boards. This system is not open for public use. Specifically, NASA personnel and procurement operations are regarded with some sensitivity. Contractors must renegotiate their contracts. The Fair and Open Procurement Act does not look kindly to those having inside information. Contractors and outsiders caught using this type of information can expect severe penalities. Unauthorized access attempts may subject you to a fine and/or imprisonment in accordance with Title 18, USC, Section 1030. If in fact you should should learn of unauthorized access, contact NASA personnel. Claims have been made on this news group about fraud and waste. None have ever been substantiated to any significant degree. Readers detecting Fraud, Waste, Abuse, or Mismanagement should contact the NASA Inspector General (24-hours) at 800-424-9183 (can be anonymous) or write NASA Inspector General P.O. Box 23089 L'enfant Plaza Station Washington DC 20024 NEXT: FAQ #3/15 - Online (and some offline) sources of images, data, etc. ------------------------------ Date: 3 May 1993 12:16:01 -0400 From: Jon Leech Subject: Space FAQ 04/15 - Calculations Newsgroups: sci.astro,sci.space,sci.answers,news.answers Archive-name: space/math Last-modified: $Date: 93/05/03 12:08:07 $ PERFORMING CALCULATIONS AND INTERPRETING DATA FORMATS COMPUTING SPACECRAFT ORBITS AND TRAJECTORIES References that have been frequently recommended on the net are: "Fundamentals of Astrodynamics" Roger Bate, Donald Mueller, Jerry White 1971, Dover Press, 455pp $8.95 (US) (paperback). ISBN 0-486-60061-0 NASA Spaceflight handbooks (dating from the 1960s) SP-33 Orbital Flight Handbook (3 parts) SP-34 Lunar Flight Handbook (3 parts) SP-35 Planetary Flight Handbook (9 parts) These might be found in university aeronautics libraries or ordered through the US Govt. Printing Office (GPO), although more information would probably be needed to order them. M. A. Minovitch, _The Determination and Characteristics of Ballistic Interplanetary Trajectories Under the Influence of Multiple Planetary Attractions_, Technical Report 32-464, Jet Propulsion Laboratory, Pasadena, Calif., Oct, 1963. The title says all. Starts of with the basics and works its way up. Very good. It has a companion article: M. Minovitch, _Utilizing Large Planetary Perubations for the Design of Deep-Space Solar-Probe and Out of Ecliptic Trajectories_, Technical Report 32-849, JPL, Pasadena, Calif., 1965. You need to read the first one first to realy understand this one. It does include a _short_ summary if you can only find the second. Contact JPL for availability of these reports. "Spacecraft Attitude Dynamics", Peter C. Hughes 1986, John Wiley and Sons. "Celestial Mechanics: a computational guide for the practitioner", Lawrence G. Taff, (Wiley-Interscience, New York, 1985). Starts with the basics (2-body problem, coordinates) and works up to orbit determinations, perturbations, and differential corrections. Taff also briefly discusses stellar dynamics including a short discussion of n-body problems. COMPUTING PLANETARY POSITIONS More net references: Van Flandern & Pullinen, _Low-Precision Formulae for Planetary Positions_, Astrophysical J. Supp Series, 41:391-411, 1979. Look in an astronomy or physics library for this; also said to be available from Willmann-Bell. Gives series to compute positions accurate to 1 arc minute for a period + or - 300 years from now. Pluto is included but stated to have an accuracy of only about 15 arc minutes. _Multiyear Interactive Computer Almanac_ (MICA), produced by the US Naval Observatory. Valid for years 1990-1999. $55 ($80 outside US). Available for IBM (order #PB93-500163HDV) or Macintosh (order #PB93-500155HDV). From the NTIS sales desk, (703)-487-4650. I believe this is intended to replace the USNO's Interactive Computer Ephemeris. _Interactive Computer Ephemeris_ (from the US Naval Observatory) distributed on IBM-PC floppy disks, $35 (Willmann-Bell). Covers dates 1800-2049. "Planetary Programs and Tables from -4000 to +2800", Bretagnon & Simon 1986, Willmann-Bell. Floppy disks available separately. "Fundamentals of Celestial Mechanics" (2nd ed), J.M.A. Danby 1988, Willmann-Bell. A good fundamental text. Includes BASIC programs; a companion set of floppy disks is available separately. "Astronomical Formulae for Calculators" (4th ed.), J. Meeus 1988, Willmann-Bell. "Astronomical Algorithms", J. Meeus 1991, Willmann-Bell. If you actively use one of the editions of "Astronomical Formulae for Calculators", you will want to replace it with "Astronomical Algorithms". This new book is more oriented towards computers than calculators and contains formulae for planetary motion based on modern work by the Jet Propulsion Laboratory, the U.S. Naval Observatory, and the Bureau des Longitudes. The previous books were all based on formulae mostly developed in the last century. Algorithms available separately on diskette. "Practical Astronomy with your Calculator" (3rd ed.), P. Duffett-Smith 1988, Cambridge University Press. "Orbits for Amateurs with a Microcomputer", D. Tattersfield 1984, Stanley Thornes, Ltd. Includes example programs in BASIC. "Orbits for Amateurs II", D. Tattersfield 1987, John Wiley & Sons. "Astronomy / Scientific Software" - catalog of shareware, public domain, and commercial software for IBM and other PCs. Astronomy software includes planetarium simulations, ephemeris generators, astronomical databases, solar system simulations, satellite tracking programs, celestial mechanics simulators, and more. Andromeda Software, Inc. P.O. Box 605 Amherst, NY 14226-0605 COMPUTING CRATER DIAMETERS FROM EARTH-IMPACTING ASTEROIDS Astrogeologist Gene Shoemaker proposes the following formula, based on studies of cratering caused by nuclear tests. (1/3.4) D = S S c K W : crater diameter in km g p f n (1/6) S = (g /g ) : gravity correction factor for bodies other than g e t Earth, where g = 9.8 m/s^2 and g is the surface e t gravity of the target body. This scaling is cited for lunar craters and may hold true for other bodies. (1/3.4) S = (p / p ) : correction factor for target density p , p a t t p = 1.8 g/cm^3 for alluvium at the Jangle U a crater site, p = 2.6 g/cm^3 for average rock on the continental shields. C : crater collapse factor, 1 for craters <= 3 km in diameter, 1.3 for larger craters (on Earth). (1/3.4) K : .074 km / (kT TNT equivalent) n empirically determined from the Jangle U nuclear test crater. 3 2 19 W = pi * d * delta * V / (12 * 4.185 * 10 ) : projectile kinetic energy in kT TNT equivalent given diameter d, velocity v, and projectile density delta in CGS units. delta of around 3 g/cm^3 is fairly good for an asteroid. An RMS velocity of V = 20 km/sec may be used for Earth-crossing asteroids. Under these assumptions, the body which created the Barringer Meteor Crater in Arizona (1.13 km diameter) would have been about 40 meters in diameter. More generally, one can use (after Gehrels, 1985): Asteroid Number of objects Impact probability Impact energy diameter (km) (impacts/year) (* 5*10^20 ergs) 10 10 10^-8 10^9 1 1 000 10^-6 10^6 0.1 100 000 10^-4 10^3 assuming simple scaling laws. Note that 5*10^20 ergs = 13 000 tons TNT equivalent, or the energy released by the Hiroshima A-bomb. References: Gehrels, T. 1985 Asteroids and comets. _Physics Today_ 38, 32-41. [an excellent general overview of the subject for the layman] Shoemaker, E.M. 1983 Asteroid and comet bombardment of the earth. _Ann. Rev. Earth Planet. Sci._ 11, 461-494. [very long and fairly technical but a comprehensive examination of the subject] Shoemaker, E.M., J.G. Williams, E.F. Helin & R.F. Wolfe 1979 Earth-crossing asteroids: Orbital classes, collision rates with Earth, and origin. In _Asteroids_, T. Gehrels, ed., pp. 253-282, University of Arizona Press, Tucson. Cunningham, C.J. 1988 _Introduction to Asteroids: The Next Frontier_ (Richmond: Willman-Bell, Inc.) [covers all aspects of asteroid studies and is an excellent introduction to the subject for people of all experience levels. It also has a very extensive reference list covering essentially all of the reference material in the field.] MAP PROJECTIONS AND SPHERICAL TRIGNOMETRY Two easy-to-find sources of map projections are the "Encyclopaedia Brittanica", (particularly the older volumes) and a tutorial appearing in _Graphics Gems_ (Academic Press, 1990). The latter was written with simplicity of exposition and suitability of digital computation in mind (spherical trig formulae also appear, as do digitally-plotted examples). More than you ever cared to know about map projections is in John Snyder's USGS publication "Map Projections--A Working Manual", USGS Professional Paper 1395. This contains detailed descriptions of 32 projections, with history, features, projection formulas (for both spherical earth and ellipsoidal earth), and numerical test cases. It's a neat book, all 382 pages worth. This one's $20. You might also want the companion volume, by Snyder and Philip Voxland, "An Album of Map Projections", USGS Professional Paper 1453. This contains less detail on about 130 projections and variants. Formulas are in the back, example plots in the front. $14, 250 pages. You can order these 2 ways. The cheap, slow way is direct from USGS: Earth Science Information Center, US Geological Survey, 507 National Center, Reston, VA 22092. (800)-USA-MAPS. They can quote you a price and tell you where to send your money. Expect a 6-8 week turnaround time. A much faster way (about 1 week) is through Timely Discount Topos, (303)-469-5022, 9769 W. 119th Drive, Suite 9, Broomfield, CO 80021. Call them and tell them what you want. They'll quote a price, you send a check, and then they go to USGS Customer Service Counter and pick it up for you. Add about a $3-4 service charge, plus shipping. A (perhaps more accessible) mapping article is: R. Miller and F. Reddy, "Mapping the World in Pascal", Byte V12 #14, December 1987 Contains Turbo Pascal procedures for five common map projections. A demo program, CARTOG.PAS, and a small (6,000 point) coastline data is available on CompuServe, GEnie, and many BBSs. Some references for spherical trignometry are: _Spherical Astronomy_, W.M. Smart, Cambridge U. Press, 1931. _A Compendium of Spherical Astronomy_, S. Newcomb, Dover, 1960. _Spherical Astronomy_, R.M. Green, Cambridge U. Press., 1985 (update of Smart). _Spherical Astronomy_, E Woolard and G.Clemence, Academic Press, 1966. PERFORMING N-BODY SIMULATIONS EFFICIENTLY "Computer Simulation Using Particles" R. W. Hockney and J. W. Eastwood (Adam Hilger; Bristol and Philadelphia; 1988) "The rapid evaluation of potential fields in particle systems", L. Greengard MIT Press, 1988. A breakthrough O(N) simulation method. Has been parallelized. L. Greengard and V. Rokhlin, "A fast algorithm for particle simulations," Journal of Computational Physics, 73:325-348, 1987. "An O(N) Algorithm for Three-dimensional N-body Simulations", MSEE thesis, Feng Zhao, MIT AILab Technical Report 995, 1987 "Galactic Dynamics" J. Binney & S. Tremaine (Princeton U. Press; Princeton; 1987) Includes an O(N^2) FORTRAN code written by Aarseth, a pioneer in the field. Hierarchical (N log N) tree methods are described in these papers: A. W. Appel, "An Efficient Program for Many-body Simulation", SIAM Journal of Scientific and Statistical Computing, Vol. 6, p. 85, 1985. Barnes & Hut, "A Hierarchical O(N log N) Force-Calculation Algorithm", Nature, V324 # 6096, 4-10 Dec 1986. L. Hernquist, "Hierarchical N-body Methods", Computer Physics Communications, Vol. 48, p. 107, 1988. INTERPRETING THE FITS IMAGE FORMAT If you just need to examine FITS images, use the ppm package (see the comp.graphics FAQ) to convert them to your preferred format. For more information on the format and other software to read and write it, see the sci.astro.fits FAQ. SKY (UNIX EPHEMERIS PROGRAM) The 6th Edition of the Unix operating system came with several software systems not distributed because of older media capacity limitations. Included were an ephmeris, a satellite track, and speech synthesis software. The ephmeris, sky(6), is available within AT&T and to sites possessing a Unix source code license. The program is regarded as Unix source code. Sky is <0.5MB. Send proof of source code license to E. Miya MS 258-5 NASA Ames Research Center Moffett Field, CA 94035-1000 eugene@orville.nas.nasa.gov THREE-DIMENSIONAL STAR/GALAXY COORDINATES To generate 3D coordinates of astronomical objects, first obtain an astronomical database which specifies right ascension, declination, and parallax for the objects. Convert parallax into distance using the formula in part 6 of the FAQ, convert RA and declination to coordinates on a unit sphere (see some of the references on planetary positions and spherical trignometry earlier in this section for details on this), and scale this by the distance. Two databases useful for this purpose are the Yale Bright Star catalog (sources listed in FAQ section 3) or "The Catalogue of Stars within 25 parsecs of the Sun" (in pub/SPACE/FAQ/stars.data and stars.doc on ames.arc.nasa.gov). NEXT: FAQ #5/15 - References on specific areas ------------------------------ End of Space Digest Volume 16 : Issue 519 ------------------------------