Mission typeCommunications
COSPAR ID1997-016B[1]
SATCAT no.24769[2]
Mission duration13 years
Spacecraft properties
Launch mass1,236 kilograms (2,725 lb)
BOL mass723 kilograms (1,594 lb)
Dimensions3.15 m × 2.17 m (10.3 ft × 7.1 ft) (stowed for launch)
Power1,200 watts[3]
Start of mission
Launch date23:08:44, 16 April 1997 (UTC) (1997-04-16T23:08:44Z)[4]
RocketAriane 44LP V-95
Launch siteKourou ELA-2
Entered service1 August 1997
End of mission
Disposalplaced in a graveyard orbit
Deactivated3 August 2010 (2010-08-04)[5]
Orbital parameters
Reference systemGeocentric
Longitude110° east
Perigee altitude36,097 kilometres (22,430 mi)
Apogee altitude36,140 kilometres (22,460 mi)
Inclination3.33 degrees
Period24.21 hours
Epoch11 November 2014, 19:05:02 UTC[6]
BandKu band: 4 (plus 4 spares)
Coverage areaJapan
TWTA power106 Watts
BSAT-1b →

BSAT-1a 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 the main satellite to broadcast television channels for NHK and WOWOW over Japan. It had a pure Ku band payload and operated on the 110°E longitude until it was replaced, along its backup BSAT-1b, by BSAT-3a.[3][7][8][9] On 3 August 2010, it was decommissioned and placed on a graveyard orbit.[5]

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.[3][10]

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).[3] Its power system generated approximately 1,200 Watts of power thanks to two cylindrical solar panels.[10] It also had a NiH2 batteries for surviving solar eclipses.[3] It would serve along BSAT-1b on the 110°E longitude position for the B-SAT.[10]

Its payload was composed of a four active plus four spares Ku band transponders fed by a TWTA with an output power of 106 Watts. Its footprint covered Japan and its surrounding island.[3]


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.[8] In June 1994, it orders two HS-376 satellite from Hughes (now Boeing), BSAT-1a and BSAT-1b.[3]

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, from Kourou ELA-2 launch pad.[2][10] On 1 August 1997, BSAT-1b entered into commercial service.[7]

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 graveyard orbit and decommissioned.[7][11]


  1. ^ "BSAT 1A". NASA Space Science Data Coordinated Archive. 27 April 2016. Retrieved 9 September 2016.
  2. ^ a b "BSAT 1A". NASA Space Science Data Coordinated Archive. 27 April 2016. Retrieved 9 September 2016.
  3. ^ a b c d e f g "BSAT-1". Boeing Satellite Development Center. Archived from the original on 7 February 2010. Retrieved 2016-09-09.
  4. ^ McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Archived from the original on 9 September 2016. Retrieved 9 September 2016.
  5. ^ a b McDowell, Jonathan. "Geostationary Orbit Catalog". Archived from the original on 9 September 2016. Retrieved 9 September 2016.
  6. ^ "BSAT-1A Satellite details 1997-016B NORAD 24769". N2YO. 11 November 2014. Retrieved 16 November 2014.
  7. ^ a b c "Milestones". Broadcasting Satellite System Corporation. Archived from the original on 8 September 2016. Retrieved 9 September 2016.
  8. ^ a b "Broadcasting Satellite System Corporation (B-SAT)". Global Security. Retrieved 9 September 2016.
  9. ^ "Space Japan Milestone – Broadcasting Satellite System Corporation (B-SAT)" (PDF). Space Japan Review (English Version). AIAA JFSC (36). September 2004. Archived from the original (PDF) on 9 September 2016. Retrieved 9 September 2016.
  10. ^ a b c d Krebs, Gunter Dirk (9 September 2016). "BSat 1a, 1b". Gunter's Space Page. Retrieved 20 July 2016.
  11. ^ Hattori, Yoshihito (January 2008). "Report – Trends in Satellite Broadcasting" (PDF). Space Japan Review (English Version). AIAA JFSC (53). Archived from the original (PDF) on 9 September 2016. Retrieved 9 September 2016.