GSAT-7 will be put into orbit by Ariane-5 rocket from French Guiana

The Indian Space Research Organisation (ISRO) has built a dedicated satellite for the Navy which will be launched in a few months by an Ariane-5 rocket from the Kourou island in French Guiana.

The communication satellite that weighs 2.5 tonnes is currently undergoing thermo-vacuum tests at the ISRO Satellite Centre in Bangalore. But the space organisation has not so far officially acknowledged that the satellite is meant for the Navy and has given it an innocuous name, GSAT-7.

It will be one of the several satellites to be launched by Ariane-5.

“This is the first time that the ISRO is building a dedicated satellite for the Navy. It is meant for defence requirements. The Navy and other agencies [the Army and the Indian Air Force] will use it for their communication,” ISRO sources said.

The GSAT series, built by the ISRO, are communication satellites which cannot be used for surveillance.

The Navy will use GSAT-7 to communicate with its submarines, frigates, destroyers and aircraft from its centres on the shore.

The ISRO's annual report for 2011-12 has sparse information on GSAT-7. It merely says, “GSAT-7, a multi-band satellite, is planned to be launched on board a procured launcher during 2012.” The report, in another place, adds, “The satellite employs the standard 2.5 tonne bus platform with the power handling capability of around 2,600 W and a lift-off mass of 2,550 kg. All the mainframe and the payload elements have been delivered. The satellite will be ready for shipment for launch during 2012.”

Communication satellite

The ISRO's 2010-2011 report is a little more liberal with information. It says, “GSAT-7 is a multi-band satellite carrying payloads in UHF [ultra-high frequency], S-band, C-band and Ku-band…The configuration of the satellite has been finalised and the design of the new payload elements is completed. The platform systems are under fabrication and payload sub-system realisation is on-going.”

Although the ISRO planned to launch GSAT-7 in 2011 onboard an indigenous Geo-Synchronous Satellite Launch Vehicle (GSLV) from Sriharikota, it has been forced to go abroad because of its failures with its GSLV in April 2010 and December 2010. The GSLV could not put GSAT-4 into orbit in April 2010 after its indigenous cryogenic engine failed to ignite. The next GSLV flight in December 2010, with a Russian cryogenic engine, failed too. It was to have hoisted into orbit GSAT-5P.

These failures and the long time that is being taken to build the GSLV-Mark III rocket with an indigenous cryogenic engine have delayed the launch of Chandrayan-II and the ISRO's efforts to send an Indian astronaut into space.

With the GSLV with an indigenous cryogenic engine yet to prove its mettle and its performance with a Russian cryogenic engine below par, the ISRO does not want to take chances with GSAT-7.

“GSAT-7 is an operational satellite meant for the Navy. It has multi-frequencies. So we do not want to take chances,” explained the ISRO sources.