COMETS experiments for advanced mobile satellite communications and advanced satellite broadcasting

The Communications and Broadcasting Engineering Test Satellite (COMETS) was developed to evaluate Ka-band (31/21 GHz) and millimetre-wave (47/44 GHz) advanced mobile satellite communications systems, 21 GHz advanced satellite broadcasting systems, and S-band and Ka-band inter-orbit satellite communications systems. COMETS was launched because it was to become the new 'bridge' toward advanced satellite communications technologies in the next century, but the launch on 21 February 1998 regretfully failed due to premature shut down of the second stage engine of the H-II launch rocket. After this accident, the initial low elliptic orbit of COMETS was improved by the apogee engine to a larger elliptic orbit with an apogee altitude of 17 711 km, a perigee altitude of 473 km, an inclination of 30.1 degrees, and an orbital period of 319 min. Original and modified COMETS experimental plans, countermeasures in earth stations for the orbiting satellite, as well as an overview of the COMETS satellite and ground terminals are presented. Copyright (C) 2000 John Wiley & Sons, Ltd.