Countdown for Insat-4B launch from French Guyana

Mar 9, 2007, 6:30 GMT

Bangalore, March 9 (IANS) The countdown has begun for the launch of the telecommunications satellite Insat-4B, primarily meant for direct to home (DTH) television services, on Sunday from Kourou in French Guyana.

Final preparations for the launch of the satellite on board the Ariane-5 are complete.

G. Madhavan Nair, chairperson of the Indian Space Research Organisation (ISRO), satellite centre project director R.K. Rajangam and about 20 space scientists and technicians are camping at Kourou to witness the launch and coordinate the post-launch activities with their counterparts in India.

As the second satellite in the Insat-4 series, the 3,025 kg Insat-4B is carrying 12 high power Ku-band (11-14 GHz) transponders and 12 C-band (4-6 GHz) transponders to augment the capacity for DTH television services and expanding the Insat capacity for other communication and broadcasting services.

'The launch window for Ariane-5 ECA, carrying Insat-4B and another payload (Skynet 5A), has been fixed between 3:55 a.m. and 4:28 a.m. IST Sunday,' a top ISRO official told IANS here.

About 30 minutes after the launch, the Indian satellite will be placed in an elliptical geo-synchronous transfer orbit (GTO), with a perigee (nearest point to earth) of 250 km and an apogee (farthest point to earth) of 35,786 km.

The inclination of Insat-4B's GTO will be 4.5 degree with respect to the equatorial plane. The spacecraft will be manoeuvred into the 36,000 km high circular geo-synchronous orbit (GSO) from Monday by firing its liquid apogee motor (LAM) in phases.

'As the satellite nears the GSO, its dish shaped antenna reflectors and solar panels will be deployed and the satellite will be put in final 'three axis stabilised mode' to provide stability. In GSO, Insat-4B will be co-located with Insat-3A satellite at 93.5 degree east longitude,' the official said.

ISRO's Master Control Facility (MCF) at Hassan in Karnataka has been geared up to take control of the satellite after it is positioned in GTO. Besides conducting the in-orbit test of the communication payloads, the MCF will carry out regular operations and control the satellite during its 12-year life span.

'The over three-tonne satellite has been built at the ISRO satellite centre in Bangalore at a cost of Rs.2.15 billion. The launch cost is estimated to be Rs.2.25 billion. The satellite has also been insured for Rs.600 million,' the official disclosed.

The solar panels of the 50-ft satellite can generate about 5,800 watt. Three lithium ion batteries of 100 ampere-hour (Ah) capacity will generate power to maintain the satellite's key functions during eclipse periods.

The 24-year Indian National Satellite (Insat) system has revolutionised the communications system spanning telecom, meteorology, radio and television broadcasting and other vital services such as education, health, agriculture and business.

'The Insat system has become the largest domestic communication satellite system in the Asia-Pacific region, with nine spacecraft, including Kalpana-1, Gsat-2, Edusat and Insat-4A in service, with 175 transponders in C, extended C and Ku bands,' the official noted.

ISRO plans to launch Insat-4CR in mid-2007 as a replacement of the Insat-4C that was lost following the crash of the GSLV in July last year from the Satish Dhawan space centre at Sriharikota in Andhra Pradesh. It is set to carry 10-12 Ku-band transponders.

As the 175th launch of the European Space Agency's (ESA) Ariane programme and 31st launch of Ariane-5, the latest launch vehicle is also carrying Skynet-5A, a military secured communications satellite built by the Paris-based EADS Astrium.

© 2007 Indo-Asian News Service