INSAT-4B placed in GTO launched effectively from Kourou

Bangalore, Mar 12: The Indian fourth generation communication satellite INSAT-4B was today placed in geosynchronous transfer orbit (GTO) by a heavy Ariane-5 launcher that blasted off from the European Spaceport of Kourou in French Guyana in early today.

In a text book launch, the Ariane vehicle placed INSAT-4B in GTO 31 minutes after the blast off.

Satellite controllers at Master Control Facility at Hassan said all the parameters of the satellite was normal.

The launch scheduled for yesterday was postponed by a day seven minutes before the blast off, following an anomoly in the water deluge system of the launchpad.

Soonafter the launch, Indian Space Research Organisation's (ISRO) Master Control facility in Hassan had secured the signals from the satellite.

Senior ISRO officials including ISRO Chairman G Madhavan nair were at Kourou to witness the launch.

In a dual payload, Ariane in its 175th flight first launched the British Spy satellite Skynet-5A 26 minutes 40 seconds after the launch. Four minutes later it was INSAT-4B's turn to get separated from the launcher.

INSAT-4B is the second satellite in the indigenously built INSAT-4 series of geostationary satellites. Weighing 3,025 kg at lift-off, it carried a total of 24 communications transponders, of which twelve are in C-band (4-6 GHz) and the other twelve in Ku-band (11-14 GHz).

With each transponder estimated to bring in to ISRO about one million dollar a year, the 24 transponders will augment the capacity of total transponders in the INSAT constellation of satellites to 199.

Over the next few days the Satellite controllers would manoeuvre the satellite to its space home of 93.5 degrees east longitude, where it would be colocated with INSAT-3A. It would have a mission life of 12 years.

INSAT-4B would play a significant role in further expanding Direct To Home (DTH) TV broadcasting services.

ISRO would follow it up with another launch from home (Satish Dhawan Space Centre in Sriharikota) in August/September this year with INSAT-4CR (repeat) with 12 Ku Band transponders would be launched by a GSLV vehicle. The Satellite would be a replacement to the INSAT-4C satellite that was lost in July last year when a GSLV mission failed.

The Satellite which was launched in an elliptical Geosynchronous Transfer Orbit (GTO) of 250 km perigee (bearest point to earth) and 35,786 km apogee (farthest point to earth). The inclination of INSAT-4B's GTO was 4.5 degrees with respect to the equatorial plane.

As INSAT-4B neared Geosynchronous orbit 36,000 km above the earth, its dish shaped antenna reflectors and solar panels would be deployed and the satellite is put in final 'three axis stabilised mode' to provide it with the required stability.

INSAT-4B is designed for a mission life of 12 years.

Identical to its predecessor, INSAT-4B was a cuboid. With its solar panels and antennas in deployed condition in GSO, the satellite spanned about 15 meters from one end to another. The solar panels of INSAT-4B would generate about 5,800 Watt of electricity.

Three Lithium Ion batteries of 100 Ampere-hour (Ah) capacity provide electrical power to the functioning of the satellite during eclipse periods.

The 12 Ku-band high power transponders of INSAT-4B were designed for providing DTH and other services over the Indian mainland. The 12 C-band transponders were designed to provide expanded coverage over an area encompassing Indian geographical boundary, area beyond India in Southeast and Northwest regions.

For the reception of communication signals that were uplinked from the ground as well as to rebroadcast the boosted signals back, INSAT-4B has 2.2 metre and two meter diameter parabolic antenna reflectors.

The Indian National Satellite (INSAT) system was commissioned with the launch of INSAT-1B in August 1983 (INSAT-1A, the first satellite was launched in April 1982 but could not fulfill the mission). INSAT system ushered in a revolution in India's television and radio broadcasting, telecommunications and meteorological sectors. It enabled the rapid expansion of TV and modern telecommunication facilities to even the remote areas and off-shore islands.

Today, INSAT has become the largest domestic communication satellite system in the Asia-Pacific region with nine satellites in service INSAT-2E, INSAT-3A, INSAT-3B, INSAT-3C, INSAT-3E, KALPANA-1, GSAT-2, EDUSAT and INSAT-4A.

Together, the system provides 175 transponders in C, Extended C and Ku bands for a variety of communication services. Some of the INSATs also carry instruments for meteorological observation and data relay for providing meteorological services. KALPANA-1 is an exclusive meteorological satellite.

After the first generation of INSAT Satellite were built by Ford Aerospoace of the US as per ISRO's specifications, the country started building its own satellites INSAT-2 series onwards.

INSAT-2A, launched into space in July 1992, was the first indigenous INSAT to provide service. Compared to INSAT-1 series of satellites procured from abroad, INSAT-2A weighed almost twice as much and had one and a half times the communications capability and more powerful meteorological instruments. Four more satellites were launched in the INSAT-2 series between 1992 and 1999.

The last of them, INSAT-2E, is still in service.

Eleven transponders on INSAT-2E have been leased to the International Telecommunications Satellite Organisation (INTELSAT).

Four satellites, INSAT-3A, INSAT-3B, INSAT-3C and INSAT-3E, in the INSAT-3 series have been launched so far and all of them are in service. Of these, INSAT-3A was providing satellite based search and rescue services besides helping Telecommunications, TV broadcasting and Meteorological sectors.

KALPANA-1, an exclusive meteorological satellite, was launched by ISRO's PSLV in September 2002. GSAT-2 and EDUSAT were launched by GSLV in May 2003 and September 2004 respectively.

EDUSAT is a communication satellite dedicated exclusively to the field of education. INSAT-4A, specifically designed to meet DTH and other services was launched on December 22, 2005.

UNI

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