Bangalore: Countdown has begun for the launch of India's multipurpose satellite INSAT-3A early on April 9, as the European rocket Ariane-5 was transferred to the launch zone at the spaceport of Kourou in French Guyana in South America.

The process began late on April 7 night when the launcher, complete with its dual payload of the INSAT-3A and Galaxy XII of the US, emerged from the spaceport's final assembly building.

Mounted atop its mobile launch table, the Ariane-5 launch vehicle of European space consortium Arianespace moved along the 2.8 km twin rail line that links its final assembly building with the ELA-3 complex launch zone.

According to Indian Space Research Organisation (ISRO), which designed and built the 2,958 kg INSAT-3A, the launch window for the 160th flight of Ariane, carrying the spacecraft and its co-passenger Galaxy XII, is fixed between 04.19 am and 05.00 am (IST) on April 9.

The launch would be telecast live by Doordarshan (DD-1) from 3.59 am (IST) on April 9.

An ISRO spokesman said the final countdown would begin 11.30 pm (IST) on April 8 before the launch window opens.

INSAT-3A would provide telecommunication, television broadcasting, meteorology and satellite-aided search and rescue services. It carries 12 C-band, six upper extended C-band, six Ku-band and one search and rescue transponders.

INSAT-3A is the third satellite in the INSAT series, which is the largest domestic communication system in the Asia-Pacific region. INSAT-3B and INSAT-3C were launched in March 2000 and January 2002, respectively.

ISRO said the meteorological instruments consist of a very high resolution radiometer, a charge coupled device and a data relay transponder.

ISRO sources said nine of the normal C-band transponders provide expanded coverage and the remaining three have India coverage beam. All the extended C-band as well as the Ku-band transponders have India coverage beams.

A data relay transponder operating in VHF band has been incorporated for real time hydro meteorological data collection from unattended platforms located on land and river basins. The data is then relayed in extended C-band to a central location.

ISRO's master control facility (MCF) at Hassan in Karnataka would take control of INSAT-3A soon after its injection into geosynchronous transfer orbit with a perigee of 200 km and an apogee of 35,980 kms.

In the following days, operations like orbit-raising manoeuvres to take the satellite into the final geostationary orbit, deployment of solar arrays, antennas and solar sail and three-axes stabilisation would be conducted from MCF.

The MCF would also carry out regular operations and control the satellite during its design life.

PTI