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Also called HGS 5


Designation 15235 / 84093B
Launch date 31 Aug 1984
Country of origin United States
Mission Telecommunications
Geostationary orbit see below
Launch vehicle STS 16


Begin End Position
L: 31 Aug 1984 1985 101°W
1985 1993 91°W
< Oct 1993 Aug 2003 77°W, inclined
Jan 2004 Sep 2005 124.95°W, inclined (PAS 13)

End of life

Out of service 29 Sep 2005
History On August 31, 1984, SBS 4 became a part of history that few may remember. It rode aboard the first flight of Space Shuttle Discovery, known as STS 41D and was the first commercial payload to be released from Discovery's bay. The Castle Rock, Colorado, teleport provided telemetry, control, and tracking for that mission, and five of its original employees are still with PanAmSat.

Throughout the years, SBS 4 provided service over the continental United States. As it grew older, its usefulness began to wane. Larger, more power, satellites were launched and one replaced SBS 4. As SBS 4 lost its place in the commercial industry, it found a new home with Hughes Government Systems (HGS), or G2 as we know today. Along with the change in industry, SBS 4's name was changed to HGS-5.

SBS 4 was showing signs of its age. Transponders were failing, battery cells were shorting, and customers were hard to find. Surviving three times its design life of seven years, SBS 4 easily surpassed the needs of its operators. The oldest operational 376 model satellite from Boeing's production line SBS 4, was finally shut down Thursday the 29th.

External resources

sat-index articles

Technical data

Lyngsat transponder loading


Prime contractor Hughes
Platform HS-376
Mass at launch 1241 kg
Mass in orbit 725 kg
Diameter 2.16 m
Height 2.82 m (6.6 m stowed)
Stabilization Spin stabilized
DC power 1100 W
Design lifetime 7 years


Main transponders 10
Backup transponders
Power 5 transponders of 20 W (TWTA)
5 transponders of 40 W (TWTA)
Bandwidth 43 MHz
Coverage CONUS
EIRP max 46 dBW
Polarization linear H
Frequencies uplink: 14-14.5 GHz
downlink: 11.7-12.2 GHz

Transponder frequency chart (GHz)

Transponder Vertical
11.725 14.025
11.780 14.080
11.823 14.123
11.872 14.172
11.921 14.221
11.970 14.270
12.019 14.319
12.068 14.368
12.117 14.417
12.166 10 14.466

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