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BS

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 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.

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. 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.

Sources and Resources

• Adapted from: Europe and Asia in Space 1993-1994, Nicholas Johnson and David Rodvold [Kaman Sciences / Air Force Phillips Laboratory]

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