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 ; Mon, 18 Feb 91 01:38:47 -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, 18 Feb 91 01:38:43 -0500 (EST) Subject: SPACE Digest V13 #170 SPACE Digest Volume 13 : Issue 170 Today's Topics: Re: Spy satellite coverage of the Gulf Commercial Space News (1 of 5) Commercial Space News (2 of 5) 30 foot telescopes Re: Fractions (was Re: SPACE Digest V13 #124) CRRES hotline info Re: 30 foot telescopes 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: 7 Feb 91 01:20:23 GMT From: munnari.oz.au!uniwa!vax7!tgumleyle@uunet.uu.net (Liam Gumley) Subject: Re: Spy satellite coverage of the Gulf In article <4409@syma.sussex.ac.uk>, nickw@syma.sussex.ac.uk (Nick Watkins) writes: > From article <14230@ganymede.inmos.co.uk>, by conor@lion.inmos.co.uk (Conor O'Neill): >> I realise that the real details are almost certainly classified, but I would >> like to get some feel for the answers: >> 5) Are they affected by the dark, or by cloud cover, or is much of the >> sensing done in the Infra Red? > Radar isn't, apparently, I think IR will be affected by cloud cover > though. Maybe somebody who knows about weather satellites can help. Nothing classified here.... Visible sensors obviously only work during the daytime. Depending on the type of orbit, the satellite can be in sunlight for up to about 50% of the time (sun-synchronous orbit). I don't know the altitude of the KH-11, but I imagine it would be low, to maximise image spatial resolution. This probably means it does not have a sun-synchronous orbit. They are usually at an altitude of 850 km or so. Infrared sensors are usable both in the day and the night, although if you want to see targets such as vehicles or people, you would want to do it at night when the ground is cooler than the objects you are trying to see. Weather sensors have a different kind of emphasis than an recon imaging system would have. Meteorologists are typically more concerned about knowing the temperature of a given pixel accurately, rather than the spatial resolution of that pixel. Most kinds of clouds are either partly or completely opaque to both visible and infrared radiation - you can't see the ground through them. I don't know too much about radar, but at microwave wavelengths, clouds are pretty transparent. I imagine that synthetic aperture radar (SAR) technology would be used. Oceanographic SAR aims for height resolution on the scale of centimeters, so you can imagine the resolution defense sensors would be working at. Check out "Jane's all the world's satellites" - a pretty good reference. Cheers, Liam. -- tgumleyle@cc.curtin.edu.au #Liam E. Gumley, Department of Applied Physics, Curtin University of Technology# #Perth, Western Australia. >>>All opinions expressed are exclusively mine.<<<# ------------------------------ Date: 16 Feb 91 04:23:52 GMT From: cs.utexas.edu!sun-barr!olivea!oliveb!felix!dhw68k!ofa123!Wales.Larrison@rutgers.edu (Wales Larrison) Subject: Commercial Space News (1 of 5) This is the second of an irregular series on news from the commercial space business. Commentary is my own thoughts on these developments. Posted in 5 messages (My apologies - message length restrictions at my up-load point). Contents - o $200 MILLION IN SATELLITE INSURANCE CLAIMS FILED. o SATELLITE NAVIGATION "PURE PLAY" IDENTIFIED o COMET CONTRACTS SIGNED o ORBITAL SCIENCES OPENS MARKETING OFFICE IN JAPAN o SPOT IMAGE PLANNING DIVORCE FROM FRENCH GOVERNMENT? o 3 MORE COMMERCIAL LAUNCHES LICENSED o GENERAL DYNAMICS POSTS $300 M LOSS FROM COMMERCIAL SPACE Articles - ------------------------------------------------------------------ $200 MILLION IN SATELLITE INSURANCE CLAIMS FILED. Two recent satellite failures have hit the satellite insurance market with over $200 M in claims. The satellites, TDF-1 (A French national telecommunications geosat), and Superbird-A (Japanese domestic telecommunications geosat), have both failed on-orbit well before the end of their expected lifetimes - both after launch by Ariane in 1989. An immediate consequence of these losses is payment to their operators from the space insurance firms wipes out the total of profits to the insurance industry from all prior years. This will result in higher insurance rates and reduced availability of insurance as the space insurance industry will have to recover their losses. International Technology Underwriters (INTEC), one of the largest of the half- dozen firms in the space insurance market in the U.S. and abroad, has already announced plans to hike premiums and restrict coverage. Since INTEC controls about 30% of the current space insurance market, this step is expected to lead to increased rates across the board. [Commentary: these failures are failures of the satellites, and not the transportation systems. In the Superbird case, the satellite, built by Ford Aerospace, had valve that failed allowing the oxidizer needed for the bi-propellant ACS system to leak out. Over the past decade and a half, by my estimation, insurance companies have paid out about $1.4 Billion, while having collected less than $900 million in premiums. Not good business and rates must rise if the insurers are to stay in business. My guestimate is current total (launch plus operations) rates of about 20-25% will rise to about 25-30%, overall. Of course the exact rate is dependent upon the different types of launchers, satellites, and type of coverage requested. For operators of large satellite constellations, we will probably see more "self-insurance" as they try to avoid these increased insurance premiums. This also further raises a barrier for new entries into the satellite market. Ford Aerospace (now Loral) may also have taken a major blow. They have been struggling to stay in the communications satellite business. A previous satellite of theirs (INSAT-1A?), had a very similar failure, which may reduce their ability to capture new commercial business. Similarly, TDF-1 was touted as a "shining example of French technology", and was the cornerstone of the Aerospatiale's entry into the satellite communications market, as well as France's entry into Direct Broadcast Satellite TV. This failure is expected to somewhat cool this market push.] -- Wales Larrison Internet: Wales.Larrison@ofa123.fidonet.org Compuserve: >internet:Wales.Larrison@ofa123.fidonet.org -------------------------------------------------------------------------- ------------------------------ Date: 16 Feb 91 04:25:31 GMT From: pacific.mps.ohio-state.edu!linac!uwm.edu!cs.utexas.edu!sun-barr!olivea!oliveb!felix!dhw68k!ofa123!Wales.Larrison@tut.cis.ohio-state.edu (Wales Larrison) Subject: Commercial Space News (2 of 5) SATELLITE NAVIGATION "PURE PLAY" IDENTIFIED Trimble Navigation of Sunnyvale CA has been identified as a pure play for satellite navigation systems. They specialize in commercial and defense navigation units using the U.S. Global Positioning Satellite (GPS) system. They have recently gone public with a stock offering on July 1990, and are targeting the $100 million annual market for commercial GPS equipment, as well as the DOD market. They are traded on the NASDQ exchanges, currently selling for about 11 3/4 per share (very near their 52 week high), probably driven by their recent receipt of a "rush" order from the DoD for hand-held GPS navigation units for Desert Storm. [Commentary: I ran across a reference to this company in a trade publication. The only other "pure play" navigation company is Geostar, which uses their own navigation system, based upon Comsats. Geostar is having financial problems, and is not yet available for common investors. Trimble provides a much more accessible "pure play" space navigation investment. Among their interesting products is the Satellite Cruising System (AVIC-1) developed in conjunction with Pioneer Electronics of Japan, which uses road maps stored on CD-ROM with the GPS signals to provide a position of a car (or truck) on a color CRT map. Linkage with Pioneer Electronics is interesting since Pioneer is marketing this system in the high-end after-market for auto accessories - selling a package that includes a high quality CD player, AM/FM tuner and TV to be installed in an auto after it has left the assembly line - which is a large potential market. According to the trade press, Japanese car companies are already installing over 5,000 auto navigation units per month - and competition is heating up with several firms including Mazda/Japan Radio corp. As always with any investment, you should check out the company's financial status yourselves and DO YOUR HOMEWORK on the investment to understand the risks involved. This is not a solicitation for an investment, but is provided as an point of interest to space investors. Annual reports and copies of SEC filings are available from Trimble Navigation, 645 North Mary Avenue, P.O. Box 3642, Sunnyvale, CA 94088-3642, or call 1-800-TRIMBLE.] -- Wales Larrison Internet: Wales.Larrison@ofa123.fidonet.org Compuserve: >internet:Wales.Larrison@ofa123.fidonet.org -------------------------------------------------------------------------- ------------------------------ Date: 17 Feb 91 18:28:27 GMT From: ghot@g.ms.uky.edu (Allan Adler) Subject: 30 foot telescopes According to a book I am reading on telescope making, if one could make a 30 foot mirror, one could see the disk of a star other than the sun, something which has never been seen. I assume that means enlarging the image of a star so that it looks like the sun looks, like a disk and not like a point. Can someone confirm that a mirror of that size would be adequate for that purpose ? I'm also curious about the problems of building and using such a telescope (relax, I am not thinking of doing this myself...). I am told that the weight of a 30 foot telescope mirror would cause strains in the glass that would in turn affect the optics. But why does the mirror have to be made of glass ? With all the experimentation with materials, why has no substitute been found for glass ? And even if one insists on glass, why could such a mirror not be made and used in outer space, where gravity would not be such a problem ? I'm also told of something called NTT's (New Technology Telescopes) where instead of using a single piece mirror, one uses a lot of smaller mirrors and coordinates their movements so that they behave like one big mirror. If the US government can contemplate placing complicated Star Wars technology in space, why can't it contemplate coordinating the pieces of a 30 foot NTT mirror in orbit ? But of course, there is the Hubble, which I regrettably know nothing about ? What size is the Hubble ? Allan Adler ghot@ms.uky.edu ------------------------------ Date: 18 Feb 91 03:59:39 GMT From: zephyr.ens.tek.com!tektronix!sequent!crg5!szabo@uunet.uu.net (Nick Szabo) Subject: Re: Fractions (was Re: SPACE Digest V13 #124) In article <1648@borg.cs.unc.edu> leech@vivaldi.cs.unc.edu (Jonathan Leech) writes: >In article <21154@crg5.UUCP> szabo@crg5.UUCP (Nick Szabo) writes: >>Coincidentally enough, the typical communications satellite also costs >>1/10 of 1% of our GNP, and pays for itself. The smaller space probes > > Comsats cost $3 billion? This is news to me. Thanks for the correction -- the approximation should be 1/100 of 1%. The figure for Fred was correct at 1%, or 100 times the cost of a comsat (c. $300 million vs. $30 billion). -- Nick Szabo szabo@sequent.com Embrace Change... Keep the Values... Hold Dear the Laughter... ------------------------------ Date: 7 Feb 91 22:23:25 GMT From: att!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!warper.jhuapl.edu!sterner@ucbvax.Berkeley.EDU (Ray Sterner) Subject: CRRES hotline info The CRRES hot-line (205-544-5356) at 4:50 pm EST Thu 7 Feb, 1991 gave the following information. There will be two releases in February, a high altitude barium release and a high altitude lithium release. All times below are Central Standard Time (as given on the hot-line). The possible release times are: 9 Feb 8:00 pm to 12:00 am at 30 min intervals. 11 Feb 9:15 pm to 1:15 am at 30 min intervals. 13 Feb 10:30 pm to 2:30 am at 30 min intervals. 16 Feb 9:00 pm to 11:30 am at 30 min intervals. 18 Feb 11:20 pm, 11:50 pm, 12:20 am, 12:40 am. The hot-line stated that moonlight was considered in selecting the intervals late in the month. Unfortunately there are too many possible release times (37) to allow posting of the release altazimuths as I did for early releases. All I can suggest is that you call the hot-line closer to the release time to get the latest times. Also make sure you convert the times from Central Standard Time to your time zone. I would like to thank Mike McCants for sending me a CRRES orbital calculation for the earlier releases, perhaps if Mike or somebody else posts the sub-satellite latitude and longitude and satellite altitude for the possible release times those of you that have the program I posted in January can compute altazimuths for your location. Ray Sterner sterner%str.decnet@warper.jhuapl.edu Johns Hopkins University North latitude 39.16 degrees. Applied Physics Laboratory West longitude 76.90 degrees. Laurel, MD 20723-6099 ------------------------------ Date: 17 Feb 91 19:08:57 GMT From: pacific.mps.ohio-state.edu!linac!uwm.edu!wuarchive!usc!elroy.jpl.nasa.gov!jarthur!nntp-server.caltech.edu!palmer@tut.cis.ohio-state.edu (David Palmer) Subject: Re: 30 foot telescopes ghot@s.ms.uky.edu (Allan Adler) writes: >According to a book I am reading on telescope making, if one could make >a 30 foot mirror, one could see the disk of a star other than the sun, >something which has never been seen. I assume that means enlarging the >image of a star so that it looks like the sun looks, like a disk and not >like a point. The disk of Betelgeuse has been seen, using a puny 17 foot mirror (200" Palomar) back in the 70's. Betelgeuse is a big star. However, it requires fancy techniques (in this case, Speckle imaging) to compensate for the distorting effects of the atmosphere. >Can someone confirm that a mirror of that size would be adequate for that >purpose ? >I'm also curious about the problems of building and using such a telescope >(relax, I am not thinking of doing this myself...). I am told that the >weight of a 30 foot telescope mirror would cause strains in the glass that >would in turn affect the optics. But why does the mirror have to be >made of glass ? With all the experimentation with materials, why has no >substitute been found for glass ? And even if one insists on glass, why >could such a mirror not be made and used in outer space, where gravity >would not be such a problem ? I'm also told of something called NTT's >(New Technology Telescopes) where instead of using a single piece mirror, >one uses a lot of smaller mirrors and coordinates their movements so that >they behave like one big mirror. If the US government can contemplate >placing complicated Star Wars technology in space, why can't it contemplate >coordinating the pieces of a 30 foot NTT mirror in orbit ? But of course, >there is the Hubble, which I regrettably know nothing about ? What size is >the Hubble ? A 33-foot telescope is currently being built on the top of Mauna Kea. The Keck 10 meter telescope uses 36 hexagonal glass mirrors, with feedback mechanisms to keep all of the mirrors in postion relative to eachother at the sub-angstrom level. Official 'first light' was December 1990, when only 8 mirrors were in place and it had only as much aperture as (but better image quality than) the 200" at Palomar. It will be fully operational, with all of the mirror segments, later this year. However, once you get past half a meter or so of aperture, resolution is determined by the atmosphere, rather than by the diameter of the optics. If you want diffraction-limited images you have to use special tricks that only work for bright stars. A 10m telescope in space is not likely in the near future, given the trouble we're having with the puny 2.4m, single-mirror Hubble telescope. -- David Palmer palmer@gap.cco.caltech.edu ...rutgers!cit-vax!gap.cco.caltech.edu!palmer "Operator, get me the number for 911" --Homer Simpson ------------------------------ End of SPACE Digest V13 #170 *******************