Date: Wed, 5 May 93 07:59:10 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #532 To: Space Digest Readers Precedence: bulk Space Digest Wed, 5 May 93 Volume 16 : Issue 532 Today's Topics: Astro/Space Frequently Seen Acronyms Cape York is dead; Long Live PNG! Drag-free satellites Gamma Ray Bursters. WHere are they. HST Servicing Mission large accelerations revisited Looking for DC-X ftp source Philosophy Quest. How Boldly? 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: 5 May 1993 00:00:10 -0400 From: Mark Bradford Subject: Astro/Space Frequently Seen Acronyms Newsgroups: sci.astro,sci.space,sci.space.shuttle,news.answers Archive-name: space/acronyms Edition: 8 Acronym List for sci.astro, sci.space, and sci.space.shuttle: Edition 8, 1992 Dec 7 Last posted: 1992 Aug 27 This list is offered as a reference for translating commonly appearing acronyms in the space-related newsgroups. If I forgot or botched your favorite acronym, please let me know! Also, if there's an acronym *not* on this list that confuses you, drop me a line, and if I can figure it out, I'll add it to the list. Note that this is intended to be a reference for *frequently seen* acronyms, and is most emphatically *not* encyclopedic. If I incorporated every acronym I ever saw, I'd soon run out of disk space! :-) The list will be posted at regular intervals, every 30 days. All comments regarding it are welcome; I'm reachable as bradfrd2@ncar.ucar.edu. Note that this just tells what the acronyms stand for -- you're on your own for figuring out what they *mean*! Note also that the total number of acronyms in use far exceeds what I can list; special-purpose acronyms that are essentially always explained as they're introduced are omitted. Further, some acronyms stand for more than one thing; as of Edition 3 of the list, these acronyms appear on multiple lines, unless they're simply different ways of referring to the same thing. Thanks to everybody who's sent suggestions since the first version of the list, and especially to Garrett A. Wollman (wollman@griffin.uvm.edu), who is maintaining an independent list, somewhat more verbose in character than mine, and to Daniel Fischer (dfi@specklec.mpifr-bonn.mpg.de), who is maintaining a truly HUGE list (535 at last count) of acronyms and terms, mostly in German (which I read, fortunately). Special thanks this time to Ken Hollis at NASA, who sent me a copy of NASA Reference Publication 1059 Revised: _Space Transportation System and Associated Payloads: Glossary, Acronyms, and Abbreviations_, a truly mammoth tome -- almost 300 pages of TLAs. Special Bonus! At the end of this posting, you will find a perl program written by none other than Larry Wall, whose purpose is to scramble the acronym list in an entertaining fashion. Thanks, Larry! A&A: Astronomy and Astrophysics AAO: Anglo-Australian Observatory AAS: American Astronomical Society AAS: American Astronautical Society AAVSO: American Association of Variable Star Observers ACE: Advanced Composition Explorer ACRV: Assured Crew Return Vehicle (or) Astronaut Crew Rescue Vehicle ADFRF: Ames-Dryden Flight Research Facility (was DFRF) (NASA) AGN: Active Galactic Nucleus AGU: American Geophysical Union AIAA: American Institute of Aeronautics and Astronautics AIPS: Astronomical Image Processing System AJ: Astronomical Journal ALEXIS: Array of Low Energy X-ray Imaging Sensors ALPO: Association of Lunar and Planetary Observers ALS: Advanced Launch System ANSI: American National Standards Institute AOA: Abort Once Around (Shuttle abort plan) AOCS: Attitude and Orbit Control System Ap.J: Astrophysical Journal APM: Attached Pressurized Module (a.k.a. Columbus) APU: Auxiliary Power Unit ARC: Ames Research Center (NASA) ARTEMIS: Advanced Relay TEchnology MISsion ASA: Astronomical Society of the Atlantic ASI: Agenzia Spaziale Italiano ASRM: Advanced Solid Rocket Motor ATDRS: Advanced Tracking and Data Relay Satellite ATLAS: Atmospheric Laboratory for Applications and Science ATM: Amateur Telescope Maker ATO: Abort To Orbit (Shuttle abort plan) AU: Astronomical Unit AURA: Association of Universities for Research in Astronomy AW&ST: Aviation Week and Space Technology (a.k.a. AvLeak) AXAF: Advanced X-ray Astrophysics Facility BATSE: Burst And Transient Source Experiment (on CGRO) BBXRT: Broad-Band X-Ray Telescope (ASTRO package) BEM: Bug-Eyed Monster BH: Black Hole BIMA: Berkeley Illinois Maryland Array BNSC: British National Space Centre BTW: By The Way C&T: Communications & Tracking CCAFS: Cape Canaveral Air Force Station CCD: Charge-Coupled Device CCDS: Centers for the Commercial Development of Space CD-ROM: Compact Disk Read-Only Memory CFA: Center For Astrophysics CFC: ChloroFluoroCarbon CFF: Columbus Free Flyer CFHT: Canada-France-Hawaii Telescope CGRO: (Arthur Holley) Compton Gamma Ray Observatory (was GRO) CHARA: Center for High Angular Resolution Astronomy CIRRIS: Cryogenic InfraRed Radiance Instrument for Shuttle CIT: Circumstellar Imaging Telescope CM: Command Module (Apollo spacecraft) CMCC: Central Mission Control Centre (ESA) CNES: Centre National d'Etude Spatiales CNO: Carbon-Nitrogen-Oxygen CNSR: Comet Nucleus Sample Return COBE: COsmic Background Explorer COMPTEL: COMPton TELescope (on CGRO) COSTAR: Corrective Optics Space Telescope Axial Replacement CRAF: Comet Rendezvous / Asteroid Flyby CRRES: Combined Release / Radiation Effects Satellite CSM: Command and Service Module (Apollo spacecraft) CSTC: Consolidated Satellite Test Center (USAF) CTIO: Cerro Tololo Interamerican Observatory DCX: Delta Clipper eXperimental DDCU: DC-to-DC Converter Unit DFRF: Dryden Flight Research Facility (now ADFRF) DMSP: Defense Meteorological Satellite Program DOD: Department Of Defense (sometimes DoD) DOE: Department Of Energy DOT: Department Of Transportation DSCS: Defense Satellite Communications System DSN: Deep Space Network DSP: Defense Support Program (USAF/NRO) EAFB: Edwards Air Force Base ECS: Environmental Control System EDO: Extended Duration Orbiter EGRET: Energetic Gamma Ray Experiment Telescope (on CGRO) EJASA: Electronic Journal of the Astronomical Society of the Atlantic ELV: Expendable Launch Vehicle EMU: Extravehicular Mobility Unit EOS: Earth Observing System ERS: Earth Resources Satellite (as in ERS-1) ESA: European Space Agency ESO: European Southern Observatory ET: (Shuttle) External Tank ETLA: Extended Three Letter Acronym ETR: Eastern Test Range EUV: Extreme UltraViolet EUVE: Extreme UltraViolet Explorer EVA: ExtraVehicular Activity FAQ: Frequently Asked Questions FAST: Fast Auroral SnapshoT explorer FFT: Fast Fourier Transform FGS: Fine Guidance Sensors (on HST) FHST: Fixed Head Star Trackers (on HST) FIR: Far InfraRed FITS: Flexible Image Transport System FOC: Faint Object Camera (on HST) FOS: Faint Object Spectrograph (on HST) FRR: Flight-Readiness Review FTP: File Transfer Protocol FTS: Flight Telerobotic Servicer FUSE: Far Ultraviolet Spectroscopic Explorer FWHM: Full Width at Half Maximum FYI: For Your Information GAS: Get-Away Special GBT: Green Bank Telescope GCVS: General Catalog of Variable Stars GEM: Giotto Extended Mission GEO: Geosynchronous Earth Orbit GDS: Great Dark Spot GHRS: Goddard High Resolution Spectrograph (on HST) GIF: Graphics Interchange Format GLOMR: Global Low-Orbiting Message Relay GMC: Giant Molecular Cloud GMRT: Giant Meter-wave Radio Telescope GMT: Greenwich Mean Time (also called UT) GOES: Geostationary Orbiting Environmental Satellite GOX: Gaseous OXygen GPC: General Purpose Computer GPS: Global Positioning System GRO: Gamma Ray Observatory (now CGRO) GRS: Gamma Ray Spectrometer (on Mars Observer) GRS: Great Red Spot GSC: Guide Star Catalog (for HST) GSFC: Goddard Space Flight Center (NASA) GTO: Geostationary Transfer Orbit HAO: High Altitude Observatory HD: Henry Draper catalog entry HEAO: High Energy Astronomical Observatory HeRA: Hermes Robotic Arm HF: High Frequency HGA: High Gain Antenna HLC: Heavy Lift Capability HLV: Heavy Lift Vehicle HMC: Halley Multicolor Camera (on Giotto) HR: Hertzsprung-Russell (diagram) HRI: High Resolution Imager (on ROSAT) HSP: High Speed Photometer (on HST) HST: Hubble Space Telescope HUT: Hopkins Ultraviolet Telescope (ASTRO package) HV: High Voltage IAPPP: International Amateur/Professional Photoelectric Photometry IAU: International Astronomical Union IAUC: IAU Circular ICE: International Cometary Explorer IDA: International Dark-sky Association IDL: Interactive Data Language IGM: InterGalactic Medium IGY: International Geophysical Year IMHO: In My Humble Opinion IOTA: Infrared-Optical Telescope Array IOTA: International Occultation Timing Association IPS: Inertial Pointing System IR: InfraRed IRAF: Image Reduction and Analysis Facility IRAS: InfraRed Astronomical Satellite ISAS: Institute of Space and Astronautical Science (Japan) ISM: InterStellar Medium ISO: Infrared Space Observatory ISO: International Standards Organization ISPM: International Solar Polar Mission (now Ulysses) ISY: International Space Year IUE: International Ultraviolet Explorer IUS: Inertial Upper Stage JEM: Japanese Experiment Module (for SSF) JGR: Journal of Geophysical Research JILA: Joint Institute for Laboratory Astrophysics JPL: Jet Propulsion Laboratory JSC: Johnson Space Center (NASA) KAO: Kuiper Airborne Observatory KPNO: Kitt Peak National Observatory KSC: Kennedy Space Center (NASA) KTB: Cretaceous-Tertiary Boundary (from German) LANL: Los Alamos National Laboratory LaRC: Langley Research Center (NASA) LDEF: Long Duration Exposure Facility LEM: Lunar Excursion Module (a.k.a. LM) (Apollo spacecraft) LEO: Low Earth Orbit LeRC: Lewis Research Center (NASA) LEST: Large Earth-based Solar Telescope LFSA: List of Frequently Seen Acronyms (!) LGA: Low Gain Antenna LGM: Little Green Men LH: Liquid Hydrogen (also LH2 or LHX) LLNL: Lawrence-Livermore National Laboratory LM: Lunar Module (a.k.a. LEM) (Apollo spacecraft) LMC: Large Magellanic Cloud LN2: Liquid N2 (Nitrogen) LOX: Liquid OXygen LRB: Liquid Rocket Booster LSR: Local Standard of Rest LTP: Lunar Transient Phenomenon MB: Manned Base MCC: Mission Control Center MECO: Main Engine CutOff MMH: MonoMethyl Hydrazine MMT: Multiple Mirror Telescope MMU: Manned Maneuvering Unit MNRAS: Monthly Notices of the Royal Astronomical Society MOC: Mars Observer Camera (on Mars Observer) MOL: Manned Orbiting Laboratory MOLA: Mars Observer Laser Altimeter (on Mars Observer) MOMV: Manned Orbital Maneuvering Vehicle MOTV: Manned Orbital Transfer Vehicle MPC: Minor Planets Circular MRSR: Mars Rover and Sample Return MRSRM: Mars Rover and Sample Return Mission MSFC: (George C.) Marshall Space Flight Center (NASA) MTC: Man Tended Capability NACA: National Advisory Committee on Aeronautics (became NASA) NASA: National Aeronautics and Space Administration NASDA: NAtional Space Development Agency (Japan) NASM: National Air and Space Museum NASP: National AeroSpace Plane NBS: National Bureau of Standards (now NIST) NDV: NASP Derived Vehicle NERVA: Nuclear Engine for Rocket Vehicle Application NGC: New General Catalog NICMOS: Near Infrared Camera / Multi Object Spectrometer (HST upgrade) NIMS: Near-Infrared Mapping Spectrometer (on Galileo) NIR: Near InfraRed NIST: National Institute for Standards and Technology (was NBS) NLDP: National Launch Development Program NOAA: National Oceanic and Atmospheric Administration NOAO: National Optical Astronomy Observatories NRAO: National Radio Astronomy Observatory NRO: National Reconnaissance Office NS: Neutron Star NSA: National Security Agency NSF: National Science Foundation NSO: National Solar Observatory NSSDC: National Space Science Data Center NTR: Nuclear Thermal Rocket(ry) NTT: New Technology Telescope OAO: Orbiting Astronomical Observatory OCST: Office of Commercial Space Transportation OMB: Office of Management and Budget OMS: Orbital Maneuvering System OPF: Orbiter Processing Facility ORFEUS: Orbiting and Retrievable Far and Extreme Ultraviolet Spectrometer OSC: Orbital Sciences Corporation OSCAR: Orbiting Satellite Carrying Amateur Radio OSSA: Office of Space Science and Applications OSSE: Oriented Scintillation Spectrometer Experiment (on CGRO) OTA: Optical Telescope Assembly (on HST) OTHB: Over The Horizon Backscatter OTV: Orbital Transfer Vehicle OV: Orbital Vehicle PAM: Payload Assist Module PAM-D: Payload Assist Module, Delta-class PI: Principal Investigator PLSS: Portable Life Support System PM: Pressurized Module PMC: Permanently Manned Capability PMIRR: Pressure Modulated InfraRed Radiometer (on Mars Observer) PMT: PhotoMultiplier Tube PSF: Point Spread Function PSR: PulSaR PV: Photovoltaic PVO: Pioneer Venus Orbiter QSO: Quasi-Stellar Object RCI: Rodent Cage Interface (for SLS mission) RCS: Reaction Control System REM: Rat Enclosure Module (for SLS mission) RF: Radio Frequency RFI: Radio Frequency Interference RIACS: Research Institute for Advanced Computer Science RMS: Remote Manipulator System RNGC: Revised New General Catalog ROSAT: ROentgen SATellite ROUS: Rodents Of Unusual Size (I don't believe they exist) RSN: Real Soon Now RTG: Radioisotope Thermoelectric Generator RTLS: Return To Launch Site (Shuttle abort plan) SAA: South Atlantic Anomaly SAGA: Solar Array Gain Augmentation (for HST) SAMPEX: Solar Anomalous and Magnetospheric Particle EXplorer SAO: Smithsonian Astrophysical Observatory SAR: Search And Rescue SAR: Synthetic Aperture Radar SARA: Satellite pour Astronomie Radio Amateur SAREX: Search and Rescue Exercise SAREX: Shuttle Amateur Radio Experiment SAS: Space Activity Suit SAS: Space Adaptation Syndrome SAT: Synthetic Aperture Telescope S/C: SpaceCraft SCA: Shuttle Carrier Aircraft SCT: Schmidt-Cassegrain Telescope SDI: Strategic Defense Initiative SDIO: Strategic Defense Initiative Organization SEI: Space Exploration Initiative SEST: Swedish ESO Submillimeter Telescope SETI: Search for ExtraTerrestrial Intelligence SID: Sudden Ionospheric Disturbance SIR: Shuttle Imaging Radar SIRTF: Space (formerly Shuttle) InfraRed Telescope Facility SL: SpaceLab SLAR: Side-Looking Airborne Radar SLC: Space Launch Complex SLS: Space(lab) Life Sciences SMC: Small Magellanic Cloud SME: Solar Mesosphere Explorer SMEX: SMall EXplorers SMM: Solar Maximum Mission SN: SuperNova (e.g., SN1987A) SNR: Signal to Noise Ratio SNR: SuperNova Remnant SNU: Solar Neutrino Units SOFIA: Stratospheric Observatory For Infrared Astronomy SOHO: SOlar Heliospheric Observatory SPAN: Space Physics and Analysis Network SPDM: Special Purpose Dextrous Manipulator SPOT: Systeme Probatoire pour l'Observation de la Terre SPS: Solar Power Satellite SRB: Solid Rocket Booster SRM: Solid Rocket Motor SSF: Space Station Fred (er, Freedom) SSI: Solid-State Imager (on Galileo) SSI: Space Studies Institut SSME: Space Shuttle Main Engine SSPF: Space Station Processing Facility SSRMS: Space Station Remote Manipulator System SST: Spectroscopic Survey Telescope SST: SuperSonic Transport SSTO: Single Stage To Orbit STIS: Space Telescope Imaging Spectrometer (to replace FOC and GHRS) STS: Shuttle Transport System (or) Space Transportation System STScI: Space Telescope Science Institute SWAS: Submillimeter Wave Astronomy Satellite SWF: ShortWave Fading TAL: Transatlantic Abort Landing (Shuttle abort plan) TAU: Thousand Astronomical Unit (mission) TCS: Thermal Control System TDRS: Tracking and Data Relay Satellite TDRSS: Tracking and Data Relay Satellite System TES: Thermal Emission Spectrometer (on Mars Observer) TIROS: Television InfraRed Observation Satellite TLA: Three Letter Acronym TOMS: Total Ozone Mapping Spectrometer TPS: Thermal Protection System TSS: Tethered Satellite System UARS: Upper Atmosphere Research Satellite UBM: Unpressurized Berthing Mechanism UDMH: Unsymmetrical DiMethyl Hydrazine UFO: Unidentified Flying Object UGC: Uppsala General Catalog UHF: Ultra High Frequency UIT: Ultraviolet Imaging Telescope (Astro package) UKST: United Kingdom Schmidt Telescope USAF: United States Air Force USMP: United States Microgravity Payload UT: Universal Time (a.k.a. GMT, UTC, or Zulu Time) UTC: Coordinated Universal Time (a.k.a. UT) UV: UltraViolet UVS: UltraViolet Spectrometer VAB: Vehicle Assembly Building (formerly Vertical Assembly Building) VAFB: Vandenberg Air Force Base VEEGA: Venus-Earth-Earth Gravity Assist (Galileo flight path) VHF: Very High Frequency VLA: Very Large Array VLBA: Very Long Baseline Array VLBI: Very Long Baseline Interferometry VLF: Very Low Frequency VLT: Very Large Telescope VMS: Vertical Motion Simulator VOIR: Venus Orbiting Imaging Radar (superseded by VRM) VPF: Vertical Processing Facility VRM: Venus Radar Mapper (now called Magellan) WD: White Dwarf WFPC: Wide Field / Planetary Camera (on HST) WFPCII: Replacement for WFPC WIYN: Wisconsin / Indiana / Yale / NOAO telescope WSMR: White Sands Missile Range WTR: Western Test Range WUPPE: Wisconsin Ultraviolet PhotoPolarimter Experiment (Astro package) XMM: X-ray Multi Mirror XUV: eXtreme UltraViolet YSO: Young Stellar Object #!/usr/bin/perl # 'alt', An Acronym Scrambling Program, by Larry Wall $THRESHOLD = 2; srand; while (<>) { next unless /^([A-Z]\S+): */; $key = $1; $acro{$key} = $'; @words = split(/\W+/,$'); unshift(@words,$key); $off = 0; foreach $word (@words) { next unless $word =~ /^[A-Z]/; *w = $&; vec($w{$word}, $off++ % 6, 1) = 1; } } foreach $letter (A .. Z) { *w = $letter; @w = keys %w; if (@w < $THRESHOLD) { @d = `egrep '^$letter' /usr/dict/words`; chop @d; push(@w, @d); } } foreach $key (sort keys %acro) { $off = 0; $acro = $acro{$key}; $acro =~ s/((([A-Z])[A-Z]*)[a-z]*)/ &pick($3, $2, $1, ++$off) || $& /eg; print "$key: $acro"; } sub pick { local($letter, $prefix, $oldword, $off) = @_; $i = 0; if (length($prefix) > 1 && index($key,$prefix) < 0) { if ($prefix eq $oldword) { $prefix = ''; } else { $prefix = $letter; } } if (length($prefix) > 1) { local(*w) = substr($prefix,0,1); do { $word = $w[rand @w]; } until $word ne $oldword && $word =~ /^$prefix/i || ++$i > 30; $word =~ s/^$prefix/$prefix/i; $word; } elsif (length($prefix) == 1) { local(*w) = $prefix; do { $word = $w[rand @w]; } until $word ne $oldword && vec($w{$word}, $off, 1) || ++$i > 10; $word = "\u\L$word" if $word =~ tr/a-z/A-Z/; $word; } else { local(*w) = substr($oldword,0,1); do { $word = $w[rand @w]; } until $word ne $oldword && $word =~ tr/a-z/A-Z/ == 0 || ++$i > 30; $word; } } -- Mark Bradford (bradfrd2@ncar.ucar.edu) <> To err is human, to moo bovine. "It's an ill wind that gathers no moss." ------------------------------ Date: Wed, 5 May 93 05:00:11 GMT From: Michael Nielsen Subject: Cape York is dead; Long Live PNG! Newsgroups: sci.space In article <1993May5.024115.11024@bby.com.au> gnb@leo.bby.com.au (Gregory N. Bond) writes: >A story appeard on the (Australian) ABC radio news last night that is >of interest. It is also mentioned in "The Australian Financial >Review" this morning (4/5/93), p14. (Don't say I don't give >references!) > >Space Transportation Systems is the company that was the preferred >bidder for the Cape York space port, with a prominant polititian >(Ahern, ex-Premier of Queensland) at its head. There was a >one-last-time, firm-and-this-time-we-mean-it deadline for STS to line >up funding for CY that expired without a whisper in December. > >Last night there was an announcement by the Prime Minister of Papua >New Guinea (PNG, an island nation to the north of Australia and east >of Indonesia - basically half the huge blob just north of Cape York, >the pointy bit on the east edge of Australia that was the preferred >site for the space port.). STS has been given an in-principle >go-ahead for the establishmnent of a commercial spaceport on an as-yet >unchosen PNG equatorial island. The project was predicted to cost >about $USD 920m. Talks with internation funding sources are $US0.920 that extremelly cheap :-> (m == 10^-3 usually). >continuing, and STS is "confident about their success." A feasability >study (a $mil or so) is about to begin and could be completed by the >end of 1993. > >This pretty much implies that Cape York is dead, and the report said >as much. More details as they come to hand. Sorry I just couldn't help my self mike -- ----------------------------------------------------------------------- JOKE == (:->) Michael Nielsen @ 1993 cemn@groper.jcu.edu.au Disclamer :- I'm Innocent ------------------------------------------------------------------------ ------------------------------ Date: 4 May 93 11:35:19 GMT From: steveg@arc.ug.eds.com Subject: Drag-free satellites Newsgroups: sci.space isaackuo@skippy.berkeley.edu (Isaac Kuo) writes: > > Well, you can certainly express any smooth function as the sum of an infinite > number of harmonic functions. I wouldn't, and neither would any other > mathematician, call such summands "harmonics". > As a mathematician myself, I'd call the terms harmonics, by extension to the general (musical) usage. Jargon, prehaps, but standard jargon. > In any case, the small difference from spherical that the Earth is is > ridiculously small. Even counting all of the mountains, etc. that make the > Earth bumpy, the Earth is closer to a sphere than the smoothest billiard > ball. > > Even if the Earth were significantly flattenned, it would be flattenned on > the axis of rotation, and thus the gravitational field does not rotate and > thus no orbiting satellite can derive energy from the non-changing > gravitational field. The difference between polar & equatorial diameters is ~1/300 diameter; and there *are* non rotationally symmetric distortions; which are in the main generated by density gradients & movements in the mantle. ------------------------------ Date: 5 May 1993 03:29:57 GMT From: "David M. Palmer" Subject: Gamma Ray Bursters. WHere are they. Newsgroups: sci.astro,sci.space Lines: 24 Message-Id: <1s7cblINN4du@gap.caltech.edu> References: <1radsr$att@access.digex.net> <1rbl0eINNip4@gap.caltech.edu> <1993Apr27.132255.12653@tpl68k0.tplrd.tpl.oz.au> Nntp-Posting-Host: alumni.caltech.edu Sender: news@CRABAPPLE.SRV.CS.CMU.EDU Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU alien@acheron.amigans.gen.nz (Ross Smith) writes: >I don't know what you mean by 'edged', but surely there are two other >possibilities for an isotropic distribution: near interstellar (up to >~100 pc, i.e. within the disc), or the Galaxy's corona? You see fewer faint (presumably distant) bursts than you would expect from the number of bright (presumably nearby) bursts, assuming that they are uniformly distributed in space for as far as we can see. We are near (within 10% of) the center of a spherical distribution of gamma-ray burst sources. Near insterstellar would not show the deficit of faint bursts. Galactic Halo sources would have to be distributed with a typical radius of ~80 kpc (we are at ~8 kpc from the Galactic center). About half the people in the field mostly believe, (and most people about half believe), that GRBs are from our Galaxy, according to a show of hands at a conference last October. But top scientists are still baffled, as the press would say. -- David M. Palmer palmer@alumni.caltech.edu palmer@tgrs.gsfc.nasa.gov ------------------------------ Date: 5 May 1993 01:44:00 -0700 From: Dan Tilque Subject: HST Servicing Mission Newsgroups: sci.space,sci.space.shuttle,sci.astro >prb@access.digex.net (Pat) writes: >> >> After all the space walking, they are going to re-boost the HST's >> orbit. I think right now it's sitting at 180 miles up, >> they would like 220. If it's currently at 180 miles altitude, it's dropped considerably since it was launched. The original orbit was about 600 Km, if I recall correctly. --- Dan Tilque -- dant@techbook.com ------------------------------ Date: Wed, 5 May 1993 04:56:19 GMT From: Gary Coffman Subject: large accelerations revisited Newsgroups: sci.space In article <1s4olt$93m@access.digex.net> prb@access.digex.net (Pat) writes: > >Of course, if you are going to de-couple the pilot from the physical >frame of the aircraft, both in positioning and sensor systems. >Control systems have been decoupled for the last 10 years. > >Why not go the distance and remove the pilot. If he has to fly using >a virtual reality helmet, take him out of the aircraft, and make it >a "guided" missile. kinda like a next generation smart bomb. The problem breaks down into two parts. First is the technical problem of achieving the necessary bandwidth in the face of hostile action. It's difficult enough under the best of conditions to achieve the high bandwidth required to VR a pilot's senses, but when the enemy is actively trying to interfere, and the airspace and spectrum aren't constrained, the problem becomes very severe. A short fiber optic link is much easier to implement than open spectrum high bandwidth transmissions. Aside from merely implementing the link, a difficult enough challenge, the link's integrity must be ensured against jamming, spoofing, and capture. That adds considerable overhead to an already heavily burdened channel. The second part of the problem is psychological. A pilot on board is more highly motivated than a controller snug in a bunker hundreds of miles from the action. This shouldn't be discounted lightly. While the performance of the aircraft can be improved when not constrained by a pilot's physical limitations, the lesser degree to which the controller identifies with the aircraft and it's mission may negate these improvements in actual tactical situations. Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | | ------------------------------ Date: 5 May 1993 00:33:41 GMT From: steve hix Subject: Looking for DC-X ftp source Newsgroups: sci.space In article dsobin@cbnewsm.cb.att.com (David L. Sobin) writes: >I understand that there is an ftp site somewhere that has the latest info >on DC-X. If anyone knows the address, could you post or direct e-mail? The current (June, 1993) issue of Analog has a nice article outlining the DC project goals and all. Even a few sketches. -- "...Then anyone who leaves behind him a written manual, and likewise anyone who receives it, in the belief that such writing will be clear and certain, must be exceedingly simple-minded..." Plato, _Phaedrus_ ------------------------------------------------------- ------------------------------ Date: Wed, 5 May 93 04:56:52 GMT From: Michael Nielsen Subject: Philosophy Quest. How Boldly? Newsgroups: sci.space In article fiddler@concertina.Eng.Sun.COM (steve hix) writes: >In article <1993May3.102312.21970@hemlock.cray.com> bobo@thejester.cray.com (Bob Kierski) writes: >>In article , henry@zoo.toronto.edu (Henry Spencer) writes: >> > >It's not even that easy: > >Unless, when we come across an alien culture, we remain invisible to them, the >fact that they know we're there is probably going to have an immense effect on >them. > >An alien culture stumbling over us will also have an immense impact on us, one >that might even destroy our culture, intentionally or not. > >It's not necessary that we force our culture on the others at all. Yes however I will argue the fact that every encounter between cultures on earth there has been one which is more "powerful" than the other and it has been used to destroy the weaker culture, rather than co-existing with it. (And it has been a choice to destroy the other culture in all the cases known to me), I cannot recall a single instance in history where this has not happened. (of course I am not a historian) I believe that was what the original author was referring (I could very well be wrong), and I may have added a personal view point to it. mike -- ----------------------------------------------------------------------- JOKE == (:->) Michael Nielsen @ 1993 cemn@groper.jcu.edu.au Disclamer :- I'm Innocent ------------------------------------------------------------------------ ------------------------------ End of Space Digest Volume 16 : Issue 532 ------------------------------