Isro satellite ‘disappears’, loses five years of life

Insat-4CR recovered, but use of fuel to move it back to right orbit shortens life

CHENNAI: Here is one of the best-kept secrets of the Indian Space Research Organisation (Isro): Insat-4CR, launched by a geosynchronous satellite launch vehicle (GSLV-F04) on September 2, 2007, “disappeared” in space about a month later.

The satellite, which has 12 transponders meant for defence applications, direct-to-home (DTH) services and news gathering for television channels, was, however, “spotted” again with the help of the US-based National Aeronautics & Space Administration (Nasa) and brought back to a near geosynchronous orbit (36,000 km above earth). This took 15 days of manoeuvres, which consumed fuel normally meant for five years. This means the life of the satellite has come down from 10 years to five years.

A satellite’s life is determined by its fuel supply. As it keeps drifting in space, it has to be propelled back to the desired orbit using precious fuel.

A highly-placed source told DNA that Insat-4CR “disappeared” some time in October, almost a month after its orbit was raised for the fifth time to a near-geosynchronous orbit from the master control facility (MCF) at Hassan in Karnataka on September 7. The GSLV-F04 launch carrying Insat-4CR was critical for Isro after it lost Insat-4C #one minute after launch on July 10, 2006. Insat-4CR had a perfect launch, but the unusual drift in space was totally unexpected. Insat-4CR, weighing 2,130 kg, is identical to Insat-4C.

When its tracking systems failed to locate the satellite, Isro sought help from Nasa. The Nasa Orbital Debris Program Office located it a few days later. “Reclaiming the satellite was no mean achievement,” said the source, “but in the process, the satellite lost fuel meant for five years.”

Of the 12 transponders the satellite has, six are for Bharti’s DTH platform which is planned for launch in January 2008. Two others are for defence, one each for the Indian Railways and ONGC and the remaining two for different television channels.

Isro’s satellite communication programme director Bhaskar Narayan, however, denied any glitches to Insat-4CR. When contacted, a Bharti spokesperson refused to confirm or deny information about the satellite.

“All we can say is that our service levels and delivery schedules are unaffected,” the spokesperson said.