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BS Yuri

A year after the first CS-class satellites were launched, the BS (Broadcasting Satellite) program was inaugurated with the flight of BSE (Experimental) also known as Yuri. As the name implies, BS satellites are designed for television broadcasting and were initially developed for the Japanese Ministry of Posts and Telecommunications and for the Japan Broadcasting Corporation (NHK). All BS satellites have been located at 110 degrees E and have been of the same basic configuration: 3-axis stabilization of a rectangular spacecraft bus with two elongated solar arrays.

The Medium-Scale Broadcasting Satellite for Experimental Purposes (BSE) was an experimental communications satellite. Its main body was irregular in shape but roughly cubical. A symmetrical pair of rectangular solar panels extended wing-like, on either side of the satellite body for a total length of 8.95 m and width of 1.48 m. These were rotated for maximum solar exposure. Mounted on another side of the spacecraft was an eliptical-paraboloid antenna disk with a composite three-horn radiator designed to efficiently irradiate primary geographical areas of interest to Japan. The combined height of satellite and antenna was 3.09 m. The satellite body was 1.32 m wide by 1.19 m long.

The spacecraft used active, three-axis stabilization employing zero-momentum wheels and hydrazine thrusters. Pointing accuracy was better than 0.2 deg. The satellite was designed for a three year lifetime on location near 110 deg E. Experiments utilized 2.1, 2.3, 12, and 14 GHz frequencies for satellite control/telemetry, and TV transmission studies. The experiments involved studies of TV signal characteristics, rainfall attenuation at 12 GHz, satellite/ground terminal performance, ground/satellite frequency sharing, satellite control techniques, satellite broadcasting operations, and TV signal quality assessment.

The 350-kg BSE was followed in 1984 and 1986 by the operational and essentially identical BS-2a and BS-2b, respectively. Each spacecraft carried two active and one spare 100 W. 14/12 GHz transponders. Built by Toshiba with assistance from General Electric, the BS-2 series were designed for five years of operations. BS-2a was moved to a graveyard orbit in 1989, followed by BS-2b in 1992.

BS-2A (Broadcasting Satellite-2A) was launched by the National Space Development Agency of Japan (NASDA) from the Tanegashima Space Center 1984-01-23. It was designed to eliminate poor television reception areas and develop the technology concerning broadcasting satellites. Transmitting frequencies and output powers were 11.91928 GHz at 100 W, 11.99600 GHz at 100 W, 11.70299 GHz and 0.1 W, and 2276.99 MHz at 1.3 W.

BS-2A (Broadcasting Satellite-2A) was launched using the N-2 launch vehicle from the Tanegashima Space Center of the National Space Development Agency of Japan 1986-02-12. The national name for the satellite was Yuri-2B. The mission objectives of the BS-2 program were to eliminate poor television reception areas and to develop the technology concerning broadcasting satellites.

After losing two BS spacecraft in launch accidents (Ariane in February, 1990, and Atlas Centaur in April, 1991), the BS constellation from 1990-1994 consisted of BS-3a (August, 1990) and BS-3b (August, 1991). The BS-3 class satellites, which have experienced some difficulties, have an initial on-station mass of 550 kg and are based on the Lockheed-Martin (GE) 3000 bus. The 15-m span solar arrays provide slightly less than 1.5 kW at beginning of life. The payload includes three active and three backup 14/12 GHz transponders and a single 14/13 GHz unit. A third BS-3 named BS-3N was finally launched by Ariane on 8 July 1994. Co-located with its predecessors and with a similar payload, the spacecraft possessed a higher on-station mass of 700 kg.

BS-3A (Broadcasting Satellite-3A) was launched by the H-I launch vehicle (H22F) from the Tanegashima Space Center in Japan 1990-08-28. A follow-on to the BS-2 series providing direct boradcast service to all of Japan and the islands of Okinawa and Ogasawara, BS-3A featured more transponder output - from 100 to 120 W, an added channel - from 2 to 3, and longer life - from 5 to 7 years. An experimental 20-W wideband transponder tested high-definition TV transmission. The payload operated at 14/12 GHz.

Built by GE Astro Space and Nippon Electric Company, the satellite was based on GE's SATCOM 3000 bus and incorporated Japanese transponders, antenna and apogee kick motor. The box-shaped satellite measured 1.3 by 1.6 by 1.6 m, spanning 15 m with solar panels deployed. The shaped beam parabolic antenna extended overall height to 3.2 m on orbit. The arrays provided 1,443 W at beginning of life. As is customary with Japanese launches, the satellite was renamed in flight. Yuri (lily) reached its assigned geosynchronous station at 110 deg. e. in October. Operations were turned over to the Telecommunications Satellite Company of Japan.

BS-3B (Broadcasting Satellite-3B) was launched utilizing the H-I launch vehicle from the Tanegashima Space Center in Japan 1991-08-25. It was equipped with three 120 W transponders operating at 12/14 GHz for direct-to-home TV broadcast. Two transponders were used by the Japanese national broadcasting network, Nippon Hoso Kyokai (NHK), the other by privately owned Japan Satellite Broadcasting Co. BS-3B also hosted a full redundant backup channel, and a 20-W wideband transponder for experimental transmissions of high definition TV. Manufactured by Nippon Electric Co (NEC), the satellite was based on GE's SATCOM 3000 bus. It measured 1.3 by 1.6 by 1.6 m, with solar arrays spanning 15 m tip to tip. Once in space, the satellite's name was changed to Yuri 3B (Lily). Operational above 110 deg. e, it has a 7 to 9-year life expectancy.

BS-3N was a Japanese geostationary communications spacecraft launched from the Kourou Space Center in French Guiana by an Ariane 44L rocket 1994-07-08. It served the Pacific region countries. BSAT-3a was booked by Lockheed Martin Commercial Space Systems as part a turnkey contract with Japan's Broadcasting Satellite System Corporation (B-SAT). In preparation for the start of digital satellite broadcasting in December 2007, experimental digital satellite broadcasting commenced on March 15. The Digital Satellite Broadcasting Reception System Test Center Council conducted experimental broadcasting using the substitute BS-3N satellite. Various types of signals, including video, audio, and data are broadcast allowing receiver manufacturers to verify proper signal reception by their products.

A more powerful B-SAT (formerly BS-4) generation spacecraft is under development for a maiden launch in 1997. The Hughes-built, 1.25 metric-ton spacecraft are being developed by the newly formed B-SAT (Broadcast Satellite System) Corporation (References 175, 186-194).


  • 175. NASDA. National Space Development Agency of Japan, 1994, pp. 19-20.
  • 176. B.I. Edelson, op. cit. p. 270-277.
  • 177. S. Mansfield, "Japanese Make Progress on Experimental Comets Program", Space News, 27 June - 3 July 1994, p.8.
  • 178. "Optical Communications Tests", Aviation Week and Space Technology, 27 July 1992, p. 13.
  • 179. "Agencies Forge Pact", Space News, 12-18 December 1994, p. 23.
  • 180. "Optical Inter-Orbit Communications", Spaceflight, April 1995, pp. 116-117.
  • 181. B.I. Edelson, op. cit., pp. 259-268.
  • 182. NASDA Report No. 1, August 1988, p. 2-3.
  • 183. "French Build N-Star Units", Aviation Week and Space Technology, 4 January 1994, p. 54.
  • 184. "Japan Looks to N-Star To Recover Experiment", Space News, 30 January - 5 February 1995, p. 2.
  • 185. "NTT's N-Star-A Spacecraft To Be Complete in January", Space News, 9-15 January 1995, p. 12.
  • 186. D. J. Marcus, "G.E. Maintains Foothold in Key Japanese Market", Space News, 14-20 September 1992, p. 4.
  • 187. P. Proctor, "Broadcast Satellite Bolsters Japan's Troubled Space Programs", Aviation Week and Space Technology, 2 September 1991, p.71.
  • 188. D.J. Marcus, "Japanese Pinpoint Reason Behind Power Problem on BS-3A Satellite", Space News, 18-24 March 1991, p.16.
  • 189. D.J. Marcus, "Flaw Threatens Japanese Satellite Broadcasts", Space News, 10-16 September 1990, p. 4.
  • 190. W. Boyer, "New Japanese Consortium To Procure Two BS-4s", Space News, 29 March - 4 April 1993, p. 18.
  • 191. P. Ferguson, "Japan's Satellite Services Come Upon Tough Times", Space News, 19-25 April 1993, p. 6.
  • 192. P. Seitz, "Japanese Officials Hope BS-3N Will Break Streak of Bad Luck", Space News, 18-24 July 1994, p. 24.
  • 193. "Hughes Nets Contract for Japanese Satellites", Space News, 3-9 January 1994, p. 2.
  • 194. "News Breaks". Aviation Week and Space Technology, 8 August 1994. p. 17.
  • Adapted from: Europe and Asia in Space 1993-1994, Nicholas Johnson and David Rodvold [Kaman Sciences / Air Force Phillips Laboratory]

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