Decay watch: February 15

Alan Pickup (alan@wingar.demon.co.uk)
Mon, 15 Feb 1999 21:13:53 +0000

The solar radiation energy at 10.7 cm reached a mean value of 200 
yesterday, the highest during the current solar cycle and for 
at least 5 years. This flux (its units are 10**-22 W m**-2 Hz**-1
if anyone is interested) is a widely used indicator of upper-
atmospheric temperature and density, and its high level implies that 
satellites may be experiencing exceptionally high drag rates at 
present. This comes after a spell of relatively low drag during
which decay dates had tended to slip. Increased drag, of course, 
means that we can expect objects to run early against predictions 
from elsets more than a day or two old.

I also notice that the daily sunspot number reached 200 yesterday, again
the highest for more than five years.

Two new decayers (one already down) from this morning's launch of 
Telstar 6.
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Object: #19771 = 89- 4 E = Gorizont 17 aux motor

Decay predictions:
Source   Prediction made    Predicted decay at      Latitude Longitude
               UTC                UTC                  deg      deg

SpaceCom   Feb 11 15:15     Feb 15 11:49 +-18h        46.4 N    41.6 W
SpaceCom   Feb 12 04:41     Feb 15 05:01 +-2d         42.6 S   106.5 W
SpaceCom   Feb 13 05:45     Feb 15 05:59 +-1d         27.8 N   111.7 E
SpaceCom   Feb 14 08:49     Feb 15 08:19 +-17h        13.2 S    86.8 W
SpaceCom   Feb 14 20:19     Feb 15 07:39 +-7h          0.8 N   115.4 E
SpaceCom   Feb 15 02:33     Feb 15 07:22 +-3h         42.4 N    60.1 E
SpaceCom   Feb 15 04:52     Feb 15 07:22 +-3h         42.4 N    60.1 E
SpaceCom   Feb 15 11:49     Feb 15 07:22 +-3h         42.4 N    60.1 E

SatEvo     Feb 11 20:15     Feb 16.0 +-0.9d
SatEvo     Feb 12 20:50     Feb 15 11:29 +-15h        22 N     101 W
SatEvo     Feb 13 16:40     Feb 15 06:56 +-8h         24 N      29 W
SatEvo     Feb 14 17:00     Feb 15 11:20 +-5h         10 N     112 W
SatEvo     Feb 15 19:30     Feb 15 06:54 +-3h         10 N      44 W       

Final elset:
Gorizont 17 aux motor                            302 x 129 km
1 19771U 89004E   99046.04078946  .27796947  12456-4  76635-3 0  5047
2 19771  46.3400 196.4081 0131316  32.2990 328.5906 16.21574652163027

Note: Against my yesterday's prediction, this was running 50 seconds 
early at the epoch of the final elset some six hours prior to its decay.
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Object: #13103 = 82- 6 C = OPS 2849 deb

Decay predictions:
Source   Prediction made    Predicted decay at      Latitude Longitude
               UTC                UTC                  deg      deg

SpaceCom   Feb 12 13:04     Feb 19 10:40 +-4d        54.5 S    91.1 E
SpaceCom   Feb 14 22:09     Feb 18 19:47 +-2d        33.5 S    36.1 W

SatEvo     Feb 12 19:40     Feb 21.1 +-3d

Note: Still no further elsets since that for 99041.17
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Object: #25627 = 99- 5 B = Telstar 6 Proton rocket

Decay predictions:
Source   Prediction made    Predicted decay at      Latitude Longitude
               UTC                UTC                  deg      deg

SpaceCom   Feb 15 07:36     Feb 25 20:18 +-6d        51.6 N   158.7 E
SpaceCom   Feb 15 10:26     Feb 20 21:45 +-3d        10.2 S    88.2 W
SpaceCom   Feb 15 18:35     Feb 17 03:06 +-20h       10.5 N   159.6 W

SatEvo     Feb 15 21:00     Feb 16 23:21 +-6h        19 S      70 E

Current elset:
Telstar 6 Proton r                               212 x 153 km
1 25627U 99005B   99046.69873914  .03415912  12203-4  29104-3 0    76
2 25627  51.5982 229.3832 0045106 274.2454  85.3420 16.33803576    78

SatEvo prediction:
Telstar 6 Proton r                               202 x 149 km
1 25627U 99005B   99047.00432344  .04449995  12421-1  26362-3 0 90070
2 25627  51.5975 227.6666 0040459 275.5294  84.0091 16.36257910   122
Telstar 6 Proton r                               190 x 145 km
1 25627U 99005B   99047.30941265  .06098246  26059-1  23082-3 0 90079
2 25627  51.5966 225.9461 0034733 276.8165  82.7885 16.39414390   176
Telstar 6 Proton r                               177 x 139 km
1 25627U 99005B   99047.55299064  .09099632  66777-1  21104-3 0 90076
2 25627  51.5956 224.5659 0028501 277.8490  81.8275 16.43000762   214
Telstar 6 Proton r                               152 x 129 km
1 25627U 99005B   99047.79587646  .22895811  55578+0  22204-3 0 90073
2 25627  51.5938 223.1803 0018259 278.8857  80.9075 16.49611178   254
Telstar 6 Proton r                               139 x 122 km
1 25627U 99005B   99047.85640122  .46013287  26053+1  27548-3 0 90077
2 25627  51.5929 222.8323 0013079 279.1460  80.7059 16.53405194   261


Note: Eclipse entry occurs while southbound near 38 deg S latitude at 
~20h local time, with eclipse exit near 5 deg S while northbound 
before dawn.
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Object: #25626 = 99- 5 C = Telstar 6 Proton platform

Decay predictions:
Source   Prediction made    Predicted decay at      Latitude Longitude
               UTC                UTC                  deg      deg

SpaceCom   Feb 15 11:11     Feb 15 21:01 +-7h        40.8 S    86.3 E
SpaceCom   Feb 15 15:23     Feb 15 19:55 +-3h        25.2 N   168.0 E
SpaceCom   Feb 15 17:53     Feb 15 19:46 +-2h         3.9 S   145.4 E
SpaceCom   Feb 15 19:54     Feb 15 19:43 +-36m       12.8 S   138.9 E

SatEvo     Feb 15 20:50     Feb 15 19:25 +-90m       45 S     100 E

Final elset:
Tlstr 6 Proton plat                              173 x 148 km
1 25628U 99005C   99046.69853579  .25796969  12458-4  98542-3 0    74
2 25628  51.5902 229.3814 0019311 271.0452  88.6462 16.41911852    82
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Alan
-- 
 Alan Pickup | COSPAR 2707:   55d53m48.7s N   3d11m51.2s W   156m asl
 Edinburgh   | Home:   alan@wingar.demon.co.uk    +44 (0)131 477 9144
 Scotland    | SatEvo page:     http://www.wingar.demon.co.uk/satevo/