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CS

The Japanese CS (Communications Satellite) series has been highly successful since its debut in 1977. The prototype satellite CS (also known as Sakura) was operational from 1977 to 1985. The second generation, operational spacecraft, CS-2a and CS-2b, were launched in 1983 and continued to function until 1991 and 1990, respectively.

The current constellation is comprised of CS-3a and CS-3b (launched in 1988) and stationed at 132 degrees E and 136 degrees E. These spin-stabilized, drum-shaped (diameter of 0.2 m and height of 0.3 m) spacecraft possess an on-orbit mass of 550 kg (compared to the 350 kg CS-2 satellites) and are based on U.S. Ford Aerospace designs. The communications payload consists of 10 active plus five spare 30/20 GHz transponders and two active plus one spare 6/4 GHz transponders. The primary contractors are Mitsubishi and NEC Corporation (References 175 and 182).

By the time the design lives of CS-3a and CS-3b are reached in 1995, the next generation of satellites in the series are scheduled to be launched. Known as CS-4 or N-Star, the new spacecraft will be procured by the Nikon Telegraph and Telephone company from the U.S. and will be based on Loral's FS-1300 platform. The N-Star payload will consist of eight 14/11GHz, eleven 30/20 GHz, and five 6/4 GHz transponders and should be operational for ten years. Aerospatiale is under contract to provide unique 2.6 m by 4.5 m composite antennas for the C-band and Ku-band transponders. The N Star spacecraft may also be able to satisfy some of the objectives of the hampered ETS VI (References 175, 183-185).

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.

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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