ISRO’s latest communication satellite, INSAT-3E, was successfully launched early this morning (September 28, 2003) by the Ariane-5 launch vehicle of Arianespace. INSAT-3E is the fourth satellite in the INSAT-3 series. INSAT-3A, INSAT-3B and INSAT-3C were launched on April 10, 2003, March 22, 2000 and January 24, 2002 respectively.

The 162nd flight of Ariane (Ariane-5), with ISRO’s 2775 kg INSAT-3E, e-BIRD of EUTELSAT and SMART-1 of European Space Agency, lifted off at 4.44 am IST from Kourou, French Guyana. INSAT-3E was injected into a Geosynchronous Transfer Orbit (GTO), at 5.14 am, i.e., 30 minutes after the lift-off, in 3-axis stabilised mode, with a perigee (nearest point to earth) of 649 km and an apogee (farthest point to earth) of 35,923 km and an inclination of 7 deg. with respect to the equator. The satellite is at present orbiting the earth with an orbital period of about 10 hours 50 minutes.

The Master Control Facility (MCF) at Hassan in Karnataka acquired the first signals from INSAT-3E at 05.14 am IST. The initial health checks on the satellite indicate that the satellite’s performance is normal. MCF subsequently issued tele-commands to the satellite to make the satellite’s earth viewing face orient towards earth. The calibration of the gyros on board the satellite was also carried out.

INSAT-3E is being tracked, monitored and controlled from MCF. During the initial phase of INSAT-3E operations, MCF also utilises INMARSAT Organisation’s Telemetry, Tracking and Command (TTC) ground stations at Beijing (China), Fucino (Italy) and Lake Cowichan (Canada). The satellite’s orbit is being precisely determined by continuous ranging from the participating ground stations.

In the coming days, INSAT-3E will be raised 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. The payloads will be subsequently checked out before the commissioning of the satellite.

INSAT-3E will be positioned at 55 deg East longitude in the geosynchronous orbit. Other INSAT satellite locations are: INSAT-3A at 93.5 deg East longitude, INSAT-2E and INSAT-3B at 83 deg East longitude, INSAT-3C and KALPANA-1 at 74 deg East longitude and GSAT-2 at 48 deg East longitude.

INSAT-3E Communication Payloads comprise

  • 24 C-band transponders, having India beam coverage providing an Edge Of Coverage-Effective Isotropic Radiated Power (EOC-EIRP) of 38.5 dBW.
  • 12 upper extended C-band transponders having India beam coverage providing an EOC-EIRP of 38 dBW

INSAT-3E, with a lift off weight of 2,775 kg, has its main body in the shape of a cuboid of dimensions 2.0 m x 1.77 m x 2.8 m with solar arrays on north and south sides. When its solar panels are fully deployed in orbit, the satellite will measure 15.44 m (North-South).

The spacecraft propulsion system to take the satellite from GTO to its final geosynchronous orbit employs a 440 N Liquid Apogee Motor with 1594 kg of MON-3 (Mixed Oxides of Nitrogen) and MMH (Mono Methyl Hydrazine). The satellite will be 3-axis body stabilised in orbit using sensors, momentum and reaction wheels, magnetic torquers and eight 10 Newton and eight 22 Newton Reaction Control Thrusters. The satellite has two solar arrays together generating 2,400 Watt of electrical power backed up by two 70 Ah Nickel Hydrogen Batteries that support full payload operation during eclipse period.

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

With ISRO Satellite Centre (ISAC), Bangalore, as the lead Centre, INSAT-3E was realised with major contributions from Space Applications Centre (SAC), Ahmedabad, Liquid Propulsion Systems Centre (LPSC) at Valiamala and Bangalore, Vikram Sarabhai Space Centre (VSSC) and ISRO Inertial Systems Unit (IISU), Thiruvananthapuram. Besides, several industries in both public and private sectors have contributed to the realisation of INSAT-3E. MCF is responsible for initial phase and in-orbit operation of all geostationary satellites of ISRO.

Earlier INSAT satellites

Satellite Launch Date Launch Vehicle Remarks
INSAT-1A Apr 10, 1982 Delta 3920 Failed
INSAT-1B Aug 30, 1983 Space Shuttle Service completed as planned
INSAT-1C Jul 22, 1988 Ariane-3 Premature termination of service after 6 months of operation
INSAT-1D Jun 12, 1990 Delta 2 Service completed as planned
INSAT-2A July 10, 1992 Ariane 4 Service completed as planned
INSAT-2B July 23, 1993 Ariane 4 Service completed as planned
INSAT-2C Dec 7, 1995 Ariane 4 Service completed as planned
INSAT-2D Jun 4, 1997 Ariane 4 Premature termination of services after 3 months of operation
INSAT-2DT In-orbit procurement from Arabsat Service completed as planned
INSAT-2E Apr 3, 1999 Ariane 4 Operational
INSAT-3A April 10, 2003 Ariane 5 Operational
INSAT-3B Mar 22, 2000 Ariane 5 Operational
INSAT-3C Jan 24, 2002 Ariane 4 Operational
KALPANA-1 Sep 12, 2002 PSLV Operational
GSAT-2 May 8, 2003 GSLV In Service