"The ISRO requested them (European space authorities) to postpone the launch as we found the signal strength from one of the telemetry transmitters to be slightly less during checks," ISRO spokesman S. Krishnamurthy told AFP.

The on-board telemetry instruments track the parameters of the satellite remotely.

"We did not want to take any chances. The anomaly was detected about nine hours from the launch time. A fresh launch date will be known in about eight hours from now," Krishnamurthy said.

The launch had been due to take place at between 2249 and 2330 GMT from the space centre in Kourou, French Guyana on Tuesday.

It was to have been the first launch of an Ariane 5 since December 12, when a beefed-up version of the rocket, an Ariane 5-ECA, suddenly veered off course on its maiden flight.

Mission controllers had to blow up the launcher along with two satellites, in a failure reckoned to have cost half a billion dollars.

The rocket was to have carried two telecommunications satellites, the 2.95-tonne INSAT 3A for ISRO and the 1.76-tonne Galaxy XII for the US telecoms operator PanAmSat, into geostationary orbit.

The 2,958 kilogramme INSAT-3A was originally scheduled to be launched in mid-February but it was delayed after the December 12 incident.

The satellite, the third in INSAT 3 series, was built and designed by ISRO. It will be used for telecommunications, television broadcasting, meteorology and satellite-aided search and rescue services.

India plans to launch a series of other satellites in the coming two years and aims to send an unmanned mission to the moon in 2007.

India's space programme runs on a shoe-string budget of about 400 million dollars annually. But research costs are low, as are salaries, and development expenditure has been spread over a long period.

SPACE.WIRE