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BSAT-1b was a geostationary communications satellite designed and manufactured by Hughes (now Boeing) on the HS-376 platform. It was originally ordered and operated by the Broadcasting Satellite System Corporation (B-SAT). It was used as backup of BSAT-1a to broadcast television channels for NHK and WOWOW over Japan. It had a pure K_u band payload and operated on the 110°E longitude until it was replaced, along its twin BSAT-1a, by BSAT-3a.[2][4][6][7]

BSAT-1b

Mission type	Communication
Operator	JSAT Corporation
COSPAR ID	1998-024B[1]
SATCAT no.	25312
Mission duration	13 years
Spacecraft properties
Spacecraft	BSAT-1b
Bus	HS-376
Manufacturer	Hughes
Launch mass	1,236 kg (2,725 lb)
BOL mass	723 kg (1,594 lb)
Dimensions	3.15 m × 2.17 m (10.3 ft × 7.1 ft) (stowed for launch)[2]
Power	1.2 kW
Start of mission
Launch date	22:53, April 28, 1998 (UTC) (1998-04-28T22:53Z)[3]
Rocket	Ariane 44P V-108
Launch site	Kourou ELA-2
Contractor	Arianespace
Entered service	August 1, 1998
End of mission
Disposal	placed in a graveyard orbit
Deactivated	August 2011[4]
Orbital parameters
Reference system	Geocentric
Regime	Graveyard orbit
Semi-major axis	42,373  km
Perigee altitude	35,987.0 km
Apogee altitude	36,018.1 km
Inclination	14.5°
Period	1,446.8 minutes
Epoch	00:00:00 2016-09-08[5]
Transponders
Band	Ku band: 4 (plus 4 spares)[2]
Coverage area	Japan
TWTA power	106 Watts
B-SAT ← BSAT-1a BSAT-2a →

Satellite description

The spacecraft was designed and manufactured by Hughes on the HS-376 satellite bus. This spin-stabilized platform had two main sections. One, the spinning section, was kept rotating at 50 rpm to maintain attitude, and a despun section that was used by the payload to maintain radio coverage. The spinning section included the Star-30BP Apogee kick motor, most of the attitude control, the power subsystem and the command and telemetry subsystems. The despun section contained the communications payload, including the antennas and transponders.[2][8]

It had a launch mass of 1,236 kg (2,725 lb), a mass of 723 kg (1,594 lb) after reaching geostationary orbit and a 10-year design life. When stowed for launch, its dimensions were 3.15 m (10.3 ft) long and 2.17 m (7 ft 1 in) in diameter. With its solar panels fully extended it spanned 7.97 m (26.1 ft).[2] Its power system generated approximately 1,200 Watts of power thanks to two cylindrical solar panels.[8] It also had a NiH₂ batteries for surviving solar eclipses.[2] It would serve along BSAT-1a on the 110°E longitude position for the B-SAT.[8]

Its payload was composed of a four active plus four spares K_u band transponders fed by a TWTA with an output power of 106 Watts. Its footprint covered Japan and its surrounding island.[2]

History

Broadcasting Satellite System Corporation (B-SAT) was founded in 1993 to broadcast by satellite the analog signals of NHK and WOWOW, including analog high definition Hi-Vision channels.[6] In June 1994, it orders two HS-376 satellite from Hughes (now Boeing), BSAT-1a and BSAT-1b.[2]

During 1997 B-SAT completed its Kawaguchi and Kimitsu satellite control centers, launched and commissioned BSAT-1a.[4] At 22:53 UTC, April 28, 1998, the Ariane-44P flight V-108 successfully launched BSAT-1b, along Nilesat 101, from Kourou ELA-2 launch pad.[3][8]

On August 1, 1998, BSAT-1b entered into commercial service. In December 2000, due to launch delays of BSAT-2a, BSAT-1b started digital broadcasting services for B-SAT.[4]

During May 2005, B-SAT ordered BSAT-3a, the replacement satellite for BSAT-1a and BSAT-1b. It was successfully launched in August 2007, and accepted into the fleet the next month. During November, 2007 BSAT-3a took over the broadcasting of analog and digital signals from BSAT-1a and BSAT-1b. In August 2011, BSAT-1b was placed in a graveyard orbit and decommissioned.[4][9]

References

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