(12 March 2007 9:00 am)

Ariane 5, carrying Insat-4B and its co-passenger Skynet-5A, lifts off from the Spaceport in Kourou, French Guiana.

MUMBAI: Isro's latest satellite, Insat-4B, was successfully launched early this morning by the European Ariane-5 ECA launch vehicle from Kourou in French Guiana.

The 3,025 kg Insat-4B is the second satellite in the Insat-4 series. An identical satellite, Insat-4A, was launched by Ariane-5 on 22 December, 2005.

The lift-off was earlier scheduled for the early hours of Sunday but due to a technical hitch, the launch was aborted just seven minutes before blast-off. There were no such problems today though and the mission went off with text book precision.

With 12 high power Ku-band transponders and 12 C-band transponders, Insat-4B will further augment the Insat capacity for Direct-To-Home (DTH) television services and other communication and TV services.

The 31st flight in Ariane-5 series, carrying Isro's Insat-4B and its co-passenger, Skynet-5A of EADS Astrium, lifted off at 03:33 am Indian Standard Time (IST) from Kourou. About 30 minutes after lift-off, Insat-4B was placed in the Geosynchronous Transfer Orbit (GTO) in 3-axis stabilised mode.

Isro chairman G Madhavan Nair (at right) joins with Astrium CEO François Auque in the Spaceport's Jupiter control room to congratulate Arianespace CEO Jean-Yves Le Gall (left) on Ariane 5's successful launch.

Insat-4B is now orbiting the earth with a perigee (nearest point to earth) of 243 km and an apogee (farthest point to earth) of 35,876 km and an inclination of 4.52 deg with respect to the equator. The orbital period is about 10 hours 34 minutes.

The Master Control Facility (MCF) at Hassan in Karnataka acquired the first signals from Insat-4B at 4:02 am IST. The initial checks on the satellite have indicated normal health of the satellite. MCF subsequently issued commands to the satellite to make the earth viewing face to orient towards earth. The calibration of the gyros on board the satellite was also carried out.

Insat-4B is being tracked, monitored and controlled from MCF. During the initial phase operations, MCF also utilises Inmarsat Organisation's Telemetry, Tracking and Command (TTC) ground stations at Beijing (China), Fucino (Italy) and Lake Cowichan (Canada) besides the Isro Telemetry, Tracking and Command (Istrac) Network station at Biak in Indonesia. The satellite's orbit is being precisely determined by continuous ranging from the participating ground stations.

In the coming days, Insat-4B will be manoeuvred to its final geostationary orbit, which is about 36,000 km above the equator, by firing its 440 Newton Liquid Apogee Motor (LAM). When the satellite reaches near geosynchronous orbit, deployment of its solar panels and the two antennas will be carried out and the satellite put in its final 3-axis stabilised mode. This will be followed by trim manoeuvres to take the satellite to its designated orbital slot at 93.5 degree East longitude where it will be co-located with Insat-3A. The payloads will be checked out before the commissioning of the satellite.

Insat-4B carries the following payloads:

* 12 Ku- band 36 MHz and 27 MHz usable bandwidth Transponders (9 and 3 numbers respectively) employing 140 W TWTAs to provide an EIRP of 52 dBW over the footprint covering Indian main land.

* 12 C-band 36 MHz bandwidth transponders employing 63 W TWTA to provide an EIRP 39 dBW with expanded coverage encompassing Indian geographical boundary, area beyond India in southeast and northwest regions.

The satellite has two deployable antennas for various transmit and receive functions.

(Pictures Courtesy Arianespace.com)

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