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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
  [e-mail].  Other mail, esp. [un]subscription requests,
  should be sent to [e-mail], or, if urgent, to
             [e-mail]

----------------------------------------------------------------------

Date: 15 Jan 91 21:37:02 GMT
From: netcom!teda![e-mail]  (Donald R. Bosart)
Subject: Re: Solar Power Sats

[e-mail] (jeffrey templon) writes:

>In article <[e-mail]> [e-mail] (Ward Griffiths) writes:
>>[e-mail] (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![e-mail]  (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 <stdio.h>
#include <math.h>

#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: [e-mail]           Fax:[phone]  Voice:[phone] |
| 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([e-mail])" <[e-mail]>
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: [e-mail]
Subject: Request of subscription
X-Envelope-To: [e-mail]

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![e-mail]  (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: [phone].

       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                     [e-mail]
  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
*******************