The Indian communications satellite INSAT 4C could not reach the intended orbit due to launch failure. Indian Space Research Organisation had attempted to launch INSAT 4C from the SLP (Second Launch Pad) at Satish Dhawan Space Centre, Sriharikota on 10th July 2006.

INSAT 4C had carried twelve Ku band transponders and two solar arrays for generating power. The satellite was onboard the GSLV (Geosynchronous Satellite Launch Vehicle) and about 55 seconds after the lift-off, the launch vehicle started to careen away disorientedly when one of the four liquid rocket boosters failed to perform promptly. This was followed by explosion of the vehicle and the range safety officer manoeuvred the remnant debris to plummet into Bay of Bengal.

Failure of INSAT-4C has alerted the space engineers who became more conscious of the flaws that caused the fiasco. As an immediate corrective measure, the mission had the sequel in the form of a newer version of satellite INSAT 4CR which was referred to as a replacement satellite launched on 2nd September 2007.


INSAT 4CR was deployed into geostationary orbit, though at a lower level than was originally planned due to under-performance of the third stage carrier rocket and the duration of the mission was planned for 12 years. The spacecraft was finally manoeuvred to stay in a near-circular orbit of 35026 kilometer-perigee and 36235 km-apogee with an inclination of 0.15 degrees.

The deteriorating efficiency of INSAT 4CR at the end of more than eleven years since its launch has been compensated with the launch of GSAT 31 which was injected into space on 6th February 2019 from the European spaceport in French Guiana. The satellite GSAT 31 weighed 2536 kilograms and has been designed for a mission life of fifteen years.

Sweeping larger areas in the Arabian Sea, Indian Ocean and Bay of Bengal, the wide band transponder of GSAT 31 is capable of facilitating communications over large oceanic regions too, which is a vital feature of the present day civilization.

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