BSAT-1a was a geostationary

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth ...

designed and manufactured by

Hughes Hughes may refer to: People * Hughes (surname) * Hughes (given name) Places Antarctica * Hughes Range (Antarctica), Ross Dependency * Mount Hughes, Oates Land * Hughes Basin, Oates Land * Hughes Bay, Graham Land * Hughes Bluff, Victoria La ...

(now

Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and p ...

) on the

HS-376 The Boeing 376 (sometimes referred to as the BSS-376, and previously as the HS-376) is a communications satellite bus introduced in 1978 by Hughes Space and Communications Company. It was a spin-stabilized bus that the manufacturer claims was th ...

platform. It was originally ordered and operated by the

Broadcasting Satellite System Corporation The Broadcasting Satellite System Corporation (B-SAT) is a Japanese corporation established in April 1993 to procure, manage and lease transponders on communications satellites. Its largest stockholder, owning 49.9%, is NHK, the Japan Broadcasting ...

(B-SAT). It was used as the main satellite to broadcast television channels for

NHK , also known as NHK, is a Japanese public broadcaster. NHK, which has always been known by this romanized initialism in Japanese, is a statutory corporation funded by viewers' payments of a television license fee. NHK operates two terrestr ...

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 backup

BSAT-1b 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 o ...

, by BSAT-3a. On 3 August 2010, it was decommissioned and placed on a

graveyard orbit A graveyard orbit, also called a junk orbit or disposal orbit, is an orbit that lies away from common operational orbits. One significant graveyard orbit is a supersynchronous orbit well beyond geosynchronous orbit. Some satellites are moved into ...

Satellite description

The spacecraft was designed and manufactured by

on the

satellite bus A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are opposed to specially produced satellites. Bus- ...

. This spin-stabilized platform had two main sections. One, the spinning section, was kept rotating at 50

rpm Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines. Standards ISO 80000-3:2019 defines a unit of rotation as the dimensionl ...

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 An apogee kick motor (AKM) is a rocket motor that is regularly employed on artificial satellites to provide the final impulse to change the trajectory from the transfer orbit into its final (most commonly circular) orbit. For a satellite la ...

, 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. It had a launch mass of , a mass of after reaching geostationary orbit and a 10-year design life. When stowed for launch, its dimensions were long and in diameter. With its solar panels fully extended it spanned . Its power system generated approximately 1,200

Watt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James ...

s of power thanks to two cylindrical solar panels. It also had a NiH₂ batteries for surviving solar eclipses. It would serve along

on the 110°E longitude position for the B-SAT. Its payload was composed of a four active plus four spares K_u band

transponders In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a flight tran ...

fed by a

TWTA A traveling-wave tube (TWT, pronounced "twit") or traveling-wave tube amplifier (TWTA, pronounced "tweeta") is a specialized vacuum tube that is used in electronics to amplify radio frequency (RF) signals in the microwave range. The TWT belongs t ...

with an output power of 106

s. Its footprint covered Japan and its surrounding island.

History

(B-SAT) was founded in 1993 to broadcast by satellite the analog signals of

and WOWOW, including analog high definition

Hi-Vision MUSE (Multiple sub-Nyquist Sampling Encoding), commercially known as Hi-Vision (a contraction of HIgh-definition teleVISION) was a Japanese analog HDTV system, with design efforts going back to 1979. It used dot-interlacing and digital video co ...

channels. In June 1994, it orders two

satellite from

(now

), BSAT-1a and

. During 1997 B-SAT completed its Kawaguchi and Kimitsu satellite control centers. At 23:08:44 UTC, 16 April 1997 the Ariane-44LP flight V-95 successfully launched BSAT-1a, along

Thaicom 3 Thaicom Public Company Limited is a Thai satellite operator and provider of satellite and telecommunication services since 1991. The company operates a fleet of currently four satellites covering Asia, Oceania, and Africa. Thaicom is a subsidiar ...

, from

Kourou Kourou () is a commune in French Guiana, an overseas region and department of France in South America. Kourou is famous for being the location of the Guiana Space Centre, the main spaceport of France and the European Space Agency (ESA). It i ...

ELA-2 ELA-2, short for Ensemble de Lancement Ariane 2 (French for Ariane Launch Area 2), was a launch pad at the Centre Spatial Guyanais in French Guiana. It was used by Arianespace for two Ariane 3 launches (V17 in 1986, V25 in 1988), the second Ariane ...

launch pad. On 1 August 1997, BSAT-1b entered into commercial service. 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. On 3 August 2010, BSAT-1a was placed in a

and decommissioned.

References

{{Use British English, date=November 2014 Communications satellites in geostationary orbit Spacecraft launched in 1997 Satellites using the HS-376 bus