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 ; Mon, 3 Dec 1990 01:36:22 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 3 Dec 1990 01:35:47 -0500 (EST) Subject: SPACE Digest V12 #612 SPACE Digest Volume 12 : Issue 612 Today's Topics: sts35 orbital data Galileo's Earth-Moon Encounter Set for December 8 Re: Visual Observation of Galileo Re: Naive HST question Re: Visual Observation of Galileo Re: HST images via anonFTP and SPAN/HEPnet Re: Translunar/interplanetary shuttle? Re: HST images via anonFTP and SPAN/HEPnet Re: Total Solar Eclipses Re: $$/pound of Freedom vs LLNL (was: ELV Support...) Re: HST images via anonFTP and SPAN/HEPnet Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription notices, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: Thu, 29 Nov 90 13:19:28 PST From: trop@hls.com (Troy T. Pummill) Subject: sts35 orbital data Could someone please post the new orbital elements for sts35.... thanks trop ----------------------------------------------------------------------------- | Troy T. Pummill, N6XMV | 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! | ----------------------------------------------------------------------------- Invisible airwaves crackle with life, bright antenna bristles with the energy Emotional feedback on timeless wavelength, bearing a gift beyond price.... Almost free. "Spirit of Radio" - Rush ------------------------------ Date: 30 Nov 90 18:47:53 GMT From: acd!fetzer@handies.ucar.edu (Eric Fetzer) Subject: Galileo's Earth-Moon Encounter Set for December 8 There is an article entitled "Galileo's Earth-Moon Encounter Set for December 8" in the November 20 _Eos, Transactions of the American Geophysical Union_. For those not familiar with _Eos_, it is a weekly publication in newspaper format sent to AGU members. The contents are only slightly more technical than _Scientific American_. This article describes the scientific objectives of the encounter. These include: -- Imaging and spectral measurements (in IR, visible and UV) of large areas of the Moon hidden from Earth view. -- Remote sounding of the Earth's atmosphere, including several previously unmeasured quantities. -- Observations of dust and particle properties in local space. -- A 24 hr movie by the imaging system of the Earth flyby, similar to those from the Voyagers' flybys of the outer planets. Despite several decades of observing the Earth and Moon from space and the ground, many of these measurements will be unique. Eric Fetzer fetzer@ncar.ucar.edu ------------------------------ Date: 30 Nov 90 03:26:32 GMT From: agate!shelby!snorkelwacker.mit.edu!usc!zaphod.mps.ohio-state.edu!lavaca.uh.edu!menudo.uh.edu!lobster!lescsse!gamorris@ucbvax.Berkeley.EDU (Gary A. Morris) Subject: Re: Visual Observation of Galileo In <901128.08462687.045202@RMC.CP6> Somers_PW@RMC.CA (Somers_PW) writes: > Galileo is fast approaching its first Earth flyby. If the >Sun-Earth-Galileo geometry is right, it should be possible to >observe the spacecraft. Somewhere on Earth, that geometry >should be right. Iberia is your best spot. Warm up your Learjet :-) I was told Iberia is in Spain, but I can't find it on my map, anyone know where it is? >Unfortunately, I have been unable to obtain any info >about its present orbit or near Earth trajectory. Is there anyone >who could provide heliocentric orbital elements, or better still >some details of its actual flyby path? This ASCII diagram below isn't nearly as nice as the diagram I was given but I hope you get the idea. This is a view looking down at the North Pole of the Earth. For North America there is really no opportunity to see Galileo. "The best place to see Galileo as it does its Earth fly-by is Iberia. It will be evening twilight there. Observers might see the sunlit side of Galileo against the dark night sky before it enters Earth shadow. Observers in the Far East also have a chance to see it as it leaves Earth shadow, but they will be looking at Galileo's dark side against the lighter morning twilight sky. It will be early afternoon in Houston, so we don't have a prayer of seeing it." | | . | Earth | + | Shadow .| | . | | . | |. | 0 = North Pole .| ***** | 1 = Japan + | 1******** | 2 = Houston . |***********| 3 = Iberia ******0****3* . ooooooooooooo * = Night side ooooooooooo o = Day side ooooo2ooo + = Galileo ooooo . = Galileo's Trajectory | | V SUN In the diagram above, Galileo approaches from the upper right, passes thru the shadow and departs toward the lower left of the diagram. Many thanks to JPL for providing the original diagram and information. --GaryM -- Gary Morris Internet: lobster!lescsse!gamorris@menudo.uh.edu Lockheed (LESC), A22 UUCP: lobster!lescsse!gamorris Space Station Freedom NASAmail: gmorris/jsc/nasa Houston, Texas Internet: gmorris@nasamail.nasa.gov ------------------------------ Date: 30 Nov 90 15:01:50 GMT From: amethyst!organpipe!argus.lpl.arizona.edu!ron@noao.edu (Ron Watkins) Subject: Re: Naive HST question In regards to using space based optical telescopes as an array similar to the VLA, several people have noted the necessity of capturing the images in phase (or as close as possible) and the need for image coherence. Further reasons include: 1) High angular resolution is the goal of such arrays as the VLA, thus the optical scopes must be observing in a very narrow bandwidth or the resolution element (nominaly 1.22*lambda/D) will vary in size and blur the image. Bandwidths on the order of 100-300 angstroms would probably be appropriate as thats what is used at the 6-mirror MMT (VLA type of interferometer in the optical band). 2) Coverage in the U-V plane could be a problem. The spatial response of the optical system is generated by the overall pupil plane of all optical components. Thus you may have fantastic resolution (large seperation) but only spatial frequency components relating to the specific seperation would be in the image. For example, suppose you had an object which had many spatial constituants such as a comb-type object. If you observe this with a seperation which would cover the extreem end of the resolution then only the closest elements of the comb would be resolvable and the wider conponents would be missed. As a quick example of how you can do this yourself, Try creating a set of filled disks in a 2-D array where the disks are set to 1 and the background is set to 0. This represents your pupil plane. You can space the individual pupil disks wherever you want. Then compute the modulus squared of the Fourier Transform. This will give you the point-spread function for your pupil plane. This shows what happens to a single point source object as it passes through your optical path. Consider what would happen if you had several point sources spaced at such a seperation as they would lie in the valleys of each-others PSF. Conclusion: You can do somthing like this but you should consider what the PSF of the pupil array looks like in the U-V plane (ie what is your spatial frequency coverage) and you should try to fill in all the gaps as well as possible to get a smooth as possible PSF. The later isn't realy possible though you may get close. The optics must be in a plane as close as possible to the perpendicular of the object direction. This is it's difficult to do beam-combinition at optical wavelengths inside a computer. The speed of light is to fast for the computer to sample enough points across the wavelength to co-phase two or more different beams while at the radio wavelengths the computer can keep up as the frequency is much less. There are plans in the works for arrays of optics on I-beams that rotate in azimuth and can be changed in elevation (AZ-EL mounts) for the moon. These are just plans though and although the physical aspects of working such a structure stabley on the moon are easier, the overall construction is more difficult than on the earth. Its difficult to generate a sufficiently stable support structure on the earth for such a optical array of any significant resolution. The MMT (6.86 meters) gives a resolution element of about 15 mili-arc-seconds (mas). Ron Watkins ron@argus.lpl.arizona.edu ------------------------------ Date: 30 Nov 90 22:15:23 GMT From: tristan!loren@lll-winken.llnl.gov (Loren Petrich) Subject: Re: Visual Observation of Galileo Sounds like a nice idea, but how bright will Galileo be? Making some plausible assumptions on its size and distance and albedo (1m*1m, 10^4 km, 50%), and using the Moon as a comparison, I estimate that its apparent magnitude wll be about +9. Unless one knows EXACTLY where to look, one will not be able to see it. However, its position should be easy to calculate with precision -- the JPL people certainly know how to do _that_. :-) $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ Loren Petrich, the Master Blaster: loren@sunlight.llnl.gov Since this nodename is not widely known, you may have to try: loren%sunlight.llnl.gov@star.stanford.edu ------------------------------ Date: 1 Dec 90 04:28:15 GMT From: spacsun.rice.edu!uk1@rice.edu (Paul A. Scowen) Subject: Re: HST images via anonFTP and SPAN/HEPnet If the Saturn image you're all talking about is the one that was distributed on the first GTO tape then only the first plane has anything on it: they only used one WFPC frame to take the shot. That may make extracting it easier for the dabbler. -- Paul Scowen Department of Space Physics Rice University (uk1@spacsun.rice.edu) ------------------------------ Date: 30 Nov 90 07:21:51 GMT From: mintaka!think.com!samsung!crackers!m2c!wpi.WPI.EDU!megazone@bloom-beacon.mit.edu (MEGAZONE 23) Subject: Re: Translunar/interplanetary shuttle? In article <7633@eos.arc.nasa.gov> millard@eos.UUCP (Millard Edgerton) writes: >If the engines(mains) are not restartable, HOW DO THEY FIRE TO DE-ORBIT? >THINK ABOUT IT! No, you think about it. What engines fire deorbit burn? Can you say OMS? The SSME do not reegnite until the next mission. They are NOT RESTARTABLE. Please do start shouting until you check facts. ############################################################################### # "Calling Garland operator 7G," EVE Email megazone@wpi.wpi.edu # # MEGAZONE, aka DAYTONA, aka BRIAN BIKOWICZ Bitnet Use a gateway. Sorry. # ############################################################################### ------------------------------ Date: 30 Nov 90 22:22:32 GMT From: haven!uvaarpa!murdoch!astsun.astro.Virginia.EDU!gsh7w@ames.arc.nasa.gov (Greg Hennessy) Subject: Re: HST images via anonFTP and SPAN/HEPnet In article <9357@ncar.ucar.edu> strandwg@ncar.ucar.edu (Gary Strand) writes: # # Well, I pulled the Saturn picture over, and besides its large size (5Mb+) # I can't get 'saoimage' to show anything useful. Is there something obvious # that I'm missing? I know that the FITS file is 800x800x4 (what exactly does # the '4' mean) and it looks like it's in 16-bit color. You have to fiddle with the contrast quite a bit, and be warned, that there is a "hot" pixel in the image. The 800x800x4 means that the data is a 3 dimentional image, 800 by 800 by 4. The 4 is the four CCD's that are present in the Planetary Camera. There was a LOT of work done in going from the raw data to the pretty color picture that was given to the press. # If so, then what's the point of telling everyone about them, if only a few # people have the software and hardware to look at them? I suspect this is part of the reason WHY NASA hasn't made more publicity over the images. NASA cannot have a FITS reader for evry computer. The FITS standard was designed by professionals, for professionals. The basic format for images is pretty easy to decipher, although some variations of fits are not easy to understand. Good luck with the images. -- -Greg Hennessy, University of Virginia USPS Mail: Astronomy Department, Charlottesville, VA 22903-2475 USA Internet: gsh7w@virginia.edu UUCP: ...!uunet!virginia!gsh7w ------------------------------ Date: 30 Nov 90 04:54:36 GMT From: news-server.csri.toronto.edu!utgpu!utzoo!henry@rutgers.edu (Henry Spencer) Subject: Re: Total Solar Eclipses In article <17838@hydra.gatech.EDU> ccoprmd@prism.gatech.EDU (Matthew DeLuca) writes: >>Beware that accommodations and such are already *very* heavily booked... > >I don't know about South America, but July in Baja California is pretty >nice; just pitch a tent! If I recall what Sky&Telescope reported correctly, camping will not be allowed during the eclipse, except perhaps in designated areas, with reservations. S&T said there is a high probability that there will be police checkpoints along the road down, admitting only people with proof of accommodation. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 30 Nov 90 17:36:43 GMT From: hub.ucsb.edu!ucsbuxa!3001crad@ucsd.edu (Charles Frank Radley) Subject: Re: $$/pound of Freedom vs LLNL (was: ELV Support...) In article <9011300244.AA25261@iti.org> aws@ITI.ORG ("Allen W. Sherzer") writes: >In article <2810@polari.UUCP>: >>Once it [LLNL] is "fleshed out" its dollar per pound cost to >>weight ratio will be about the same as Freedom. >Would you mind justifying this a bit better? You have demonstrated >(by your own admission) very limited knowledge of the LLNL approach. >This is especially strange when you consider that Freedom uses >ligher material throughout and that its transport costs are five >times cheaper then the Shuttle. > Allen >-- >+---------------------------------------------------------------------------+ >|Allen W. Sherzer| I had a guaranteed military sale with ED-209. Renovation | >| aws@iti.org | programs, spare parts for 25 years. Who cares if it | >| | works or not? - Dick Jones, VP OCP Security Concepts | Certainly. 1) - without using numbers admittedly, but the lighter hull materials of LLNL only account for a small portion of the overall vehicle. Most of the mass of Freedom is in its support SYSTEMS, eg electronics, power, science experiments, thermal control etc, the hull is a small percentage. Copper wire on LLNL will weight the same as it does on Freedom, for example. (I mena in terms of pound per fott for a given gauge). 2) - the lightweight material of LLNL advantage is largely negated by being much bigger in volume than the Freedom habitable areas, because it spins. A nonspinning smaller LLNL would be more competitive. - to change the subject:- Nobody has responded to my point about long term radiation doses, which is the design driver for 90 day crew rotation. Zero-g is not the problem, so spinning the station is no advantage. LLNL, being at highdr altitude and with less shielding will need to rotate crews even more often....... Would be interested to see LLNL's numbers in that area. ------------------------------ Date: 30 Nov 90 20:50:18 GMT From: ncar.ucar.EDU!gary@handies.ucar.edu (Gary Strand) Subject: Re: HST images via anonFTP and SPAN/HEPnet Well, I pulled the Saturn picture over, and besides its large size (5Mb+) I can't get 'saoimage' to show anything useful. Is there something obvious that I'm missing? I know that the FITS file is 800x800x4 (what exactly does the '4' mean) and it looks like it's in 16-bit color. If so, then what's the point of telling everyone about them, if only a few people have the software and hardware to look at them? -- Gary Strand There is only one success -- to be able Internet: strandwg@ncar.ucar.edu to spend your life in your own way. Voicenet: (303) 497-1383 - Christopher Morley ------------------------------ End of SPACE Digest V12 #612 *******************