SBS 4

Also called HGS 5

General

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

Location

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)

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.

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

Ku-band

Main transponders	10
Backup transponders	4
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)

Horizontal Downlink	Transponder	Vertical Uplink
11.725	1	14.025
11.780	2	14.080
11.823	3	14.123
11.872	4	14.172
11.921	5	14.221
11.970	6	14.270
12.019	7	14.319
12.068	8	14.368
12.117	9	14.417
12.166	10	14.466

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V0.146 - Converted on Sun, 08 Sep 2024 16:27:17 GMT - Updated quarterly

SBS 4

General

Location

End of life

External resources

Technical data

Specifications

Ku-band

Transponder frequency chart (GHz)