Russian geosynchronous communications
satellites. Work on Ekran ("screen") began in the late 1960s,
initially using hazardous technologies. The satellite was to have been boosted
into orbit by a Proton rocket fitted with
a new high-performance upper stage using fluorine/amine propellants, and
the satellite itself was to have been powered by a 5-kilowatt nuclear reactor.
However, by 1973 both these ideas had been abandoned. The first Ekran was
launched in Oct. 1976, 27 months after Molniya
1S, the first Soviet geostationary experiment. Early Ekrans were mainly
for test purposes but also enabled 18–20 million additional Soviet
citizens to watch programs of the Central Television. Problems with the
Proton booster led to delays in putting the system into operation. The original
Ekrans were very short-lived and carried just a single transponder. In the
second half of the 1980s, they were replaced by Ekran-M's which carried
two transponders and generally kept on working well beyond their three-year
design life. The final satellite in the Ekran-M series was launched on Apr.
7, 2001, on the maiden flight of Russia's new Proton-M booster.
AND SPACE PROBES