MUMBAI: The countdown is on for the launch of India's next generation multipurpose Insat 3A satellite. Early Wednesday Insat 3A will take off on board the European launcher Ariane 5 along with with Panamsat's Galaxy XII from Kourou in French Guiana.

The mainly telecom and broadcasting satellite contains weather and search and rescue payloads. Its launch, originally planned in early 2002, has been delayed due to two major mishaps that Arianespace's launch programme had - in August 2001 and again in December last year. In March 2001, ISRO also advanced 3B ahead of 3A and again brought forward 3C in January 2002 to meet its clientele, of late a growing group of the private sector broadcasters and VSAT operators.

With this launch, Insat expects to boost its transponder capacity to over 100 through five birds in orbit. The Indian demand is projected to reach 250 transponders in the next 10 years.

Picture provides an overview of the transfer of Flight 160's Ariane 5 launcher as it nears a final turn before arriving on the launch pad. The launch pad (with its tall towers that provide protection against lightning strikes) is at the left.

Liftoff of Arianne Flight 160 is on schedule for Tuesday evening (local time in Kourou), during a launch window that begins at 7:49 pm and closes at 8:30 pm (4.19 am and 5 am IST on Wednesday). ISRO's Master Control Facility (MCF) at Hassan will take control as soon as the satellite is launched into a transfer orbit.

The Ariane-5 is scheduled to launch the INSAT-3A satellite into a geosynchronous transfer orbit (GTO) with a perigee of 200 km and an apogee of 35,980 km. The satellite will be manoeuvered to its final orbit by firing the satellite's apogee motor. Subsequently, the deployment of solar array, antennae and the solar sail will be carried out and the satellite will be commissioned after in-orbit checkout. INSAT-3A is to be located at 93.5 deg east longitude in the geostationary orbit.

INSAT-3A is the third satellite in the INSAT-3 series. INSAT-3B and INSAT-3C were launched in March 2000 and January 2002 respectively by the Ariane launch vehicle and both the satellites are now providing regular service.

INSAT-3A is a multipurpose satellite for providing telecommunications, television broadcasting, meteorological and search & rescue services. It carries 24 transponders - 12 operating in the normal C-band frequency, six in Extended C-band and six in Ku-band. Nine of the 12 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. INSAT-3A also carries a Ku-band beacon.

Another two satellites, INSAT-3D and INSAT-3E are planned for launch in the next two years followed by INSAT-4 series of satellites.

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