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 ; Wed, 16 Jan 91 22:03:50 -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, 16 Jan 91 22:03:46 -0500 (EST) Subject: SPACE Digest V13 #059 SPACE Digest Volume 13 : Issue 59 Today's Topics: Re: Solar Power Sats Re: Barium release altazimuth program Re: SPACE Digest V13 #050 Request of subscription barium/lithium altazimuths 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: 15 Jan 91 21:37:02 GMT From: netcom!teda!bosart@apple.com (Donald R. Bosart) Subject: Re: Solar Power Sats templon@copper.ucs.indiana.edu (jeffrey templon) writes: >In article <986@tsnews.Convergent.COM> ward@tsnews.Convergent.COM (Ward Griffiths) writes: >>templon@copper.ucs.indiana.edu (jeffrey templon) writes: >> >>>destruction cut by the wandering power beam. Even if it did stay on target, >>>they would be forever collecting birds and small rodents which died near >>>the receiving antennas. >> >Righto. However the thing about birds and rodents is correct I believe. >It doesn't have to do so much with the resonant frequencies of H20 which I >think is how a real microwave oven works, but that the birds and rodents >are of comparable size to the wavelengths of the radiation, giving them >a high-Q for absorbing it. This was my understanding about 12 years ago when >I last looked into it. Somebody please correct me if I am wrong! If memory serves me correctly, birds and such would probably learn in short order to avoid the area since the beam fringes would provide a warning via an unpleasantly warm sensation before any irreversible effects were endured. Also there are some passive obstacles which could be used to minimize fauna intrusion into the collection site. Another idea was to locate the collector sites on floating platforms at sea or in inhospitable deserts to minimize eco-impact further. There is a trade-off here between real-estate consumption and beam safety. The larger, less intense beams require more real-estate; the smaller, more intense beams require many more "fail-safes." >>created by power generation, I don't expect English (at least >>not the American dialect) to be a dominant language in any space >>industrialization efforts. >Urp. I have to agree with you. One of the reasons why I am applying >for post-doc positions in Europe. I just hope that this creeping >bureaucracy doesn't get them too. This EC Senate sounds a whole lot The Japanese are not sitting still. They have been making slow steady progress for some time now and the decline of American and perhaps eventually European space activities may combine with Japanese self-interest to actually go beyond the threshold. -- ------------------------------------------------------------------------------- Donald R. Bosart Teradyne EDA West !{decwrl, sun}!teda!bosart 5155 Old Ironsides Dr. 408-980-5264 Santa Clara, CA. 95054 ------------------------------ Date: 15 Jan 91 22:16:23 GMT From: sun-barr!cs.utexas.edu!samsung!umich!sharkey!cfctech!norm@apple.com (Norman J. Meluch) Subject: Re: Barium release altazimuth program Ok. I finally got the time to turn this thing into a program that I could compile. Figured there might be some others out there who want it. So here it is. - Norm. P.S. If you would like the MSDOS binary of this e-mail and I will send you the uuencoded/zipped version. P.P.S Don't forget to hack my .sig off before compiling. ------- Cut here (snip) (snip) (snip) --------------------------------- /* --------------------------------------------------------------------- barium.c : Compute altitude and azimuth of satellite barium release Original IDL source written by: Ray. Sterner, Johns Hopkins Applied Physics Lab, 10 Jan, 1991 Modified to C on a 3B2/1000 model 80 & MSDOS PC by: Norm Meluch, Chrysler Financial Corp., 15 Jan, 1991 ---------------------------------------------------------------------- Notes: This program was originally written so as to be easily translated to some other language. In the code below: RADEG = 180/pi (about 57.295779). Any text preceded by star (*) slash (/) and followed by slash (/) star (*) is a comment. The variables lat1 and long1 are the latitude and longitude of the observer. lat2 and long2 are the latitude and longitude of the sub-satellite point on the earth. The earth is assumed spherical and atmospheric refraction is ignored. Check you machine for a M_PI define in math.h. The following is based on spherical trig equations from the book "Textbook on Spherical Astronomy" by W. M. Smart. Original author's notes: I don't normaly like to use spherical trig for this type of problem because there are usually too many ambiguities. For example, the azimuth angle is really the small angle from north, so to get true azimuth a correction must be made based on the longitude difference. Also the azimuth equation seemed a bit picky, sometimes giving values slightly out of the valid function range due to round off so, the value of t was forced >= 0, and sa2 was forced <= than 1. There are special cases when you are at the north or south pole or directly under the satellite. I much prefer vector methods which don't have these problems but they involve polar/rectangular coordinate transformations which are less easily ported. This seems to work for some test cases I tried. ------------------------------------------------------------------*/ #include #include #ifndef M_PI #define M_PI 3.14159265358979323846 #endif #define RADEG (180/M_PI) #define RADIUS_OF_EARTH 6378 /* Kilometres */ main(argc, argv) int argc; char *argv[]; { char str[128]; float lat1, long1, lat2, long2, h; double colat1, colat2, dlong; double range, s, sa2, azi, t; double x, y, alt, c2, dist; fprintf(stdout, "\n ---===< Barium release altitude and azimuth >==---\n\n"); fprintf(stdout, " Please enter observation point latitude : "); gets(str); #ifdef DEBUG printf("got \"%s\"\n", str); #endif sscanf(str, "%f", &lat1); fprintf(stdout, " longitude: "); gets(str); #ifdef DEBUG printf("got \"%s\"\n", str); #endif sscanf(str, "%f", &long1); fprintf(stdout, " Now, enter sub-satellite point latitude : "); gets(str); #ifdef DEBUG printf("got \"%s\"\n", str); #endif sscanf(str, "%f", &lat2); fprintf(stdout, " longitude: "); gets(str); #ifdef DEBUG printf("got \"%s\"\n", str); #endif sscanf(str, "%f", &long2); fprintf(stdout, " Finally, enter the release altitude (km): "); gets(str); #ifdef DEBUG printf("got \"%s\"\n", str); #endif sscanf(str, "%f", &h); #ifdef DEBUG fprintf(stdout, "Obs Lat = %f\n", lat1); fprintf(stdout, "Obs Long = %f\n", long1); fprintf(stdout, "Sat Lat = %f\n", lat2); fprintf(stdout, "Sat Long = %f\n", long2); fprintf(stdout, "Sat Dist = %f\n", h); #endif /* DEBUG */ colat1 = (90 - lat1)/RADEG; /* Co-latitudes in radians. */ colat2 = (90 - lat2)/RADEG; dlong = long2 - long1; if (dlong > 180) dlong -= 360; if (dlong < -180) dlong += 360; dlong /= RADEG; /* Longitude difference in radians. */ /* ------- Range to sub-satellite point ------- */ range = acos(cos(colat1) * cos(colat2) + sin(colat1) * sin(colat2) * cos(dlong)); /* ------- Satellite azimuth ------ */ s = (colat1 + colat2 + range) / 2; if (!colat1 || !range) t = 0; else { t = (sin(s - colat1) * sin(s - range)) / (sin(colat1) * sin(range)); if (t < 0) t = 0; } sa2 = sqrt(t); if (sa2 > 1) sa2 = 1; azi = (2 * asin(sa2)) * RADEG; if (dlong > 0) azi = 360 - azi; /* ------- Satellite altitude ---------- */ x = RADIUS_OF_EARTH - (RADIUS_OF_EARTH + h) * cos(range); y = (RADIUS_OF_EARTH + h) * sin(range); if (!x) alt = 0; /* Here a To_polar routine would */ else /* clean up this mess */ if (x > 0) alt = atan(y/x) * RADEG - 90; else if (x < 0) alt = atan(y/x) * RADEG + 90; /* ------ Satellite distance ----------- */ c2 = (RADIUS_OF_EARTH * RADIUS_OF_EARTH) + ((RADIUS_OF_EARTH + h) * (RADIUS_OF_EARTH + h)) - (2 * RADIUS_OF_EARTH * (RADIUS_OF_EARTH + h) * cos(range)); if (c2 < 0) c2 = 0; dist = sqrt(c2); fprintf(stdout, "\n Azimuth of satellite (deg) = %6.1f\n", azi); fprintf(stdout, " Altitude of satellite (deg) = %6.1f\n", alt); fprintf(stdout, " Distance of satellite (km) = %6.0f\n", dist); fprintf(stdout, " Distance of sub-satellite point (km) = %6.0f\n", range * RADIUS_OF_EARTH); } -- |~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Norman J. Meluch ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| | Mail: norm@cfctech.cfc.com Fax:(313)948-4975 Voice:(313)948-4809 | | Note: The opinions expressed here are in no way to be confused with valid | |_______ideas or corporate policy.____________________________________________| ------------------------------ Date: Tue, 15 Jan 91 22:27:24 EST From: "Glen Kruszynski(434800@uottawa.bitnet)" <434800%UOTTAWA@acadvm1.uottawa.ca> Subject: Re: SPACE Digest V13 #050 Can someone please tell me how to unsub from this DL! I can seem to cancel my subscription....someone pls do it for me ------------------------------ Date: Wed, 16 Jan 91 12:18 GMT From: GERACI%CRESH0.CRES.IT@vma.cc.cmu.edu Subject: Request of subscription X-Envelope-To: space+@andrew.cmu.edu Dear Sir, my name is Michele Geraci and I a student doing a five year course in Electronic Engineering. I would be very interested in receiveing your issues. Yours Sincerely Michele Geraci ------------------------------ Date: 16 Jan 91 18:16:18 GMT From: snorkelwacker.mit.edu!usc!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!warper.jhuapl.edu!sterner@bloom-beacon.mit.edu (Ray Sterner) Subject: barium/lithium altazimuths CRRES 17/18 Jan 1991 (UT) high altitude lithium release. <<< Check the hotline for the latest predicted times >>> The IAU circular posted here last week agreed with the hotline times to within 1 minute for the window start and 4 minutes for the window end. The first table below is for the start of the window given in that IAU circular. The second table is for the IAU circular window end time. The hotline as of 12:15 pm EST Wednesday, 16 Jan gave the following possible times: 18 Jan 05:00, 05:30, 06:00, 06:30, 07:00 UT. The altitude is high, so the few minutes difference will not give position errors as big as they would be for lower altitudes. Most of the apparent position difference between the window start and end is probably due to a parallax effect as the earth rotates beneath the satellite. For Washington, DC the apparent position difference in the sky is about the same as the distance between Betelgeuse and Rigel in Orion. I have added RA and Dec to the tables. Unless you are right at the table lat, long these values will not be exact. That is also true for the altazimuth values but with RA and Dec you have the stars for reference, which makes differences more visible. Also if the release time differs from the table these values will also differ. The RA and Dec are new, I've tried to check them to see if they look reasonable, but haven't checked them against an actual release. They are provided as another means of giving the look direction. The RA and Dec are topocentric values. RA is given as a time, slightly different than the normal format, but just interpret it as hours and minutes. ------------------------- Window start ---------------------- Combined Release and Radiation Effects Satellite (CRRES) Marshall Space Flight Center hotline: 205-544-5356. Values are for a spherical earth with no atmospheric refraction. Distances in km, angles in degrees. Universal time is given. Lithium release at 05:00:57 18 Jan 1991 UT. Satellite altitude = 33586. Sub-satellite lat, long (deg) = 7.50 60.90 ************************************************* * Window end time is 07:00:00 18 Jan 1991 UT. * * Table below does NOT apply to the that time! * ************************************************* City Satellite Name Lat Long Azi Alt Dist RA Dec Anchorage, AK 61.2 149.8 87.3 -2.1 39683 09:03 -0.5 Atlanta, GA 33.8 84.4 135.1 50.1 34862 08:59 2.8 Bermuda, UK 32.3 65.8 168.7 60.2 34302 08:48 3.0 Chicago, IL 41.8 87.6 137.9 41.5 35454 08:59 1.6 Columbus, OH 40.0 83.0 142.7 45.5 35161 08:57 1.8 Dallas, TX 32.8 96.8 119.2 41.4 35460 09:05 2.9 Denver, CO 39.7 105.0 117.2 31.3 36277 09:06 1.8 Detroit, MI 42.4 83.2 144.2 43.3 35318 08:56 1.5 Edmonton, ALB 53.5 113.5 117.3 18.9 37440 09:03 0.1 El Paso, TX 31.8 106.4 109.8 33.6 36081 09:09 3.0 Flagstaff, AZ 35.3 111.7 108.4 27.9 36583 09:10 2.4 Honolulu, HI 21.3 157.8 80.5 -12.6 40871 09:18 4.1 London, UK 51.5 0.0 251.1 14.8 37851 08:24 0.3 Los Angeles, CA 34.0 118.3 102.9 22.6 37074 09:12 2.6 Mexico City, MEX 19.5 99.2 102.5 44.5 35233 09:09 5.0 Miami, FL 25.8 80.2 131.4 59.5 34339 08:58 4.1 Montreal, QUE 45.5 73.6 160.0 43.8 35280 08:51 1.1 New York, NY 40.7 74.0 157.1 48.8 34943 08:52 1.7 Paris, FR 48.8 2.3 250.3 17.2 37606 08:23 0.6 Phoenix, AZ 33.5 112.0 106.9 28.2 36556 09:11 2.7 Pittsburgh, PA 40.4 80.0 147.4 46.6 35087 08:55 1.8 San Juan, PR 18.5 66.2 154.3 75.6 33755 08:49 5.4 Salt Lake City, UT 40.8 111.9 111.8 25.7 36786 09:08 1.6 San Francisco, CA 37.8 122.3 102.1 18.3 37497 09:12 2.0 Seattle, WA 47.6 122.3 106.8 15.8 37758 09:08 0.8 St. Louis, MO 38.7 90.3 132.0 42.4 35386 09:01 2.0 Tucson, AZ 32.3 111.0 106.8 29.4 36443 09:11 2.9 Washington, DC 38.8 77.0 151.0 49.5 34896 08:54 2.0 Winnipeg, MAN 50.6 96.3 133.3 29.9 36401 09:00 0.4 ------------------------- Window end ---------------------- Lithium release at 06:56:09 18 Jan 1991 UT. Satellite altitude = 28688. Sub-satellite lat, long (deg) = 2.00 72.10 ************************************************** * Window start time is 05:00:57 18 Jan 1991 UT. * * Table below does NOT apply to that time! * ************************************************** City Satellite Name Lat Long Azi Alt Dist RA Dec Anchorage, AK 61.2 149.8 99.9 -2.8 34795 10:16 -7.2 Atlanta, GA 33.8 84.4 157.5 49.4 29974 10:05 -4.4 Bermuda, UK 32.3 65.8 192.4 52.8 29774 09:52 -4.2 Chicago, IL 41.8 87.6 156.5 39.8 30641 10:06 -5.7 Columbus, OH 40.0 83.0 162.6 43.1 30397 10:03 -5.4 Dallas, TX 32.8 96.8 137.9 44.0 30336 10:13 -4.2 Denver, CO 39.7 105.0 133.2 33.1 31170 10:16 -5.3 Detroit, MI 42.4 83.2 163.2 40.5 30588 10:03 -5.8 Edmonton, ALB 53.5 113.5 131.4 18.3 32533 10:14 -6.9 El Paso, TX 31.8 106.4 125.7 37.8 30795 10:19 -4.0 Flagstaff, AZ 35.3 111.7 123.2 31.6 31303 10:21 -4.5 Honolulu, HI 21.3 157.8 89.7 -5.7 35122 10:35 -1.8 London, UK 51.5 0.0 257.1 2.2 34242 09:31 -6.3 Los Angeles, CA 34.0 118.3 116.4 27.1 31699 10:24 -4.2 Mexico City, MEX 19.5 99.2 120.1 51.8 29828 10:18 -1.7 Miami, FL 25.8 80.2 160.6 59.8 29408 10:03 -3.0 Montreal, QUE 45.5 73.6 177.9 38.3 30756 09:57 -6.2 New York, NY 40.7 74.0 177.0 43.7 30352 09:58 -5.5 Paris, FR 48.8 2.3 255.8 4.2 34012 09:30 -6.0 Phoenix, AZ 33.5 112.0 121.6 32.4 31236 10:22 -4.2 Pittsburgh, PA 40.4 80.0 167.4 43.3 30383 10:02 -5.5 San Juan, PR 18.5 66.2 200.1 68.7 29046 09:52 -1.6 Salt Lake City, UT 40.8 111.9 126.6 28.0 31619 10:19 -5.3 San Francisco, CA 37.8 122.3 115.3 22.1 32167 10:24 -4.8 Seattle, WA 47.6 122.3 120.3 17.2 32648 10:20 -6.1 St. Louis, MO 38.7 90.3 151.2 42.0 30476 10:08 -5.2 Tucson, AZ 32.3 111.0 121.6 33.9 31108 10:22 -4.0 Washington, DC 38.8 77.0 171.9 45.6 30224 10:00 -5.3 Winnipeg, MAN 50.6 96.3 149.0 28.0 31616 10:09 -6.7 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 ------------------------------ End of SPACE Digest V13 #059 *******************