Thursday, June 10, 1999

DSCS 9431/9432

 1971-095A


Satellite 9431, the first DSCS II satellite, had a mass of 526 kg after launch. It was probably designated satellite A-1. The satellite's communications system failed in June 1973 due to an electrostatic discharge caused by charging in a substorm. This event raised awareness of the dangers of spacecraft charging in high orbit.


DSCS II A-1 
 

DateTimeEventOrbit  

1971 Nov 3  0309:06  Launch by Titan 3C  CC  
  T+1:49 Stage 1 ignition 
  T+2:02 SRM sep 
  T+4:18 Stage 1 MECO, sep  
 0314 T+5:00? Fairing sep
  T+7:40? SECO 
 0316 T+7:45? Stage 2 sep  145? x 400? x 28.6  
 0419? Transtage burn 1  320? x 37000? x 26.5? 
 0920? Transtage burn 2 
 0930? Transtage sep 
1971 Nov   Operational  GEO POR 
1971 Dec 10  1813   1436.19 35783 x 35792 x 2.6 GEO 106.1W+0.0 
1972 Feb 5    1435.89 35774 x 35791 x 2.4 GEO 111.1W+0.05W 
1973 Jun 2   Charging event, comms failed 
1973 Jun   end of ops 
1975? Moved to 81W 
1977 Feb 25    1435.89 35743 x 35821 x 1.9 GEO 81.6W+0.04W 
1978 Oct 22    1436.19 35761 x 35815 x 3.1 GEO 81.2W+0.0 
1979 Mar 1    1435.70 35749 x 35808 x 3.3 GEO 86.3W 
1979   Moved to 110W 
1979 Aug 27    1436.18 35761 x 35815 x 3.7 GEO 111.0W 
1979 Sep   Drifting GEO 110W 
1980 Jan    GEO 110W 
1980 Oct    GEO 101W 
1980 Mar 1    1435.97 35753 x 35814 x 4.0 GEO 109.7W 
1980 Jun 27    1435.91 35777 x 35789 x 4.3 GEO 104.6W+0.04 
1981    GEO 99-102W 
1982    GEO 109-111W 
1986    GEO 106W 
1988 Jun 5    1436.03 35766 x 35804 x 10.0 GEO 99.2W 
1989 Jan 16    1436.25 35776 x 35803 x 10.5 GEO 102.6W 
1990 Jan 31    1435.98 35768 x 35800 x 11.3 GEO 110.5W 
1992 Jan 31    1436.20 35764 x 35812 x 12.7 GEO 110.5W 
1994 Jan 31    1436.25 35758 x 35821 x 13.8 GEO 102.9W 
1998 Aug 5    1436.05 35753 x 35818 x 15.1 GEO 98.8W 

Payload:

  • X-band transponders

  • Earth coverage antennae; horn antenna

  • 2 narrow coverage parabolic antennae




1971-095B

Satellite 9432, the second of the first DSCS II pair, suffered an accidental spinup of its communications payload platform in Dec 1971, possibly due to spacecraft charging problems, but the satellite was successfully despun in 1972 Jun. Mass of F-2 was 526 kg.


DSCS II A-2 
 

DateTimeEventOrbit  

1971 Nov 3   Launch by Titan 3C  CK 
  Colocated DSCS F-1 GEO POR 
1971 Dec 12  0901   1435.81 35773 x 35788 x 2.6 GEO 115.6W+0.06W/d 
Dec?  Accidental spinup 
1972 Jan 9    1435.43 35568 x 35978 x 2.5 GEO 112.0W+0.1W 
1972 Feb 1    1435.53 35762 x 35788 x 2.4 GEO 89.6W+0.1W 
1972 Jun   Payload despun 
1977 Jan 31    1436.67 35750 x 35845 x 1.7 GEO 140.1E+0.1E 
1978 Feb 6    1437.02 35766 x 35842 x 2.5 GEO 15.5E+0.2E 
1979 Sep 18    1437.78 35780 x 35858x 3.6 GEO 114.1W+0.4E 
1980 May   On station  GEO 175E 
1980 Jul 6    1436.32 35773 x 35808 x 4.1 GEO 176.5E+0.0 
1980 late   Begin slow period decrease 
1980 Dec 13    1435.81 35773 x 35789 x 4.5 GEO 177.6E+0.06 
1981 Jan 5    1435.71 35770 x 35787 x 4.5 GEO 179.5E+0.09 
1981 Jan 31    1435.61 35739 x 35814 x 4.5 GEO 177.7W+0.11W 
1981 May 7    1435.08 35757 x 35776 x 4.7 GEO 160.0W+0.24W 
1981 Jul 25    1434.59 35739 x 35775 x 4.9 GEO 134.5W+0.37W 
1982 Sep 27    1435.65 35748 x 35807 x 5.7 GEO 14.1W+0.2W 
1984 Nov 9    1436.21 35782 x 35796 x 7.2 GEO 149.2E+0.04E 
1985 Feb 1    1436.55 35786 x 35804 x 7.4 GEO 141.3E+0.14E 
1988 Nov 8    1436.06 35772 x 35799 x 10.2 GEO 173.3E+0.00E 
1989 Sep 14    1434.59 35737 x 35776 x 10.9 GEO 135.1W+0.37W 
1991 Nov 24    1434.29 35746 x 35756 x 12.4 GEO 73.5E+0.4W 
1998 Aug 2    1434.85 35742 x 35781 x 15.0 GEO 56.5W+0.31W 

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