GSLV Mk-II launch vehicle on the launch pad before the liftoff of GSAT-7A military satellite

CHENNAI: Scientists in the Indian Space Research Organisation completed the fourth orbit manoeuvring operation on Monday to move GSAT-7A, the communication satellite, to its final orbit.

The satellite is now very close to its final geostationary orbit, which is around 35,786 km.

In an update, the Indian space agency said the propulsion system onboard the satellite had been used to successfully perform four orbit manoeuvring operations.

At present, the satellite is placed in an orbit with perigee (nearest point to earth) of 35,800 km and apogee (farthest point to earth) of 36,092 km with 0.2 degree inclination, which is very close to its final orbit.

The satellite, primarily meant for the Indian Air Force, was launched onboard GSLV-F11 on December 19. The rocket placed the satellite in a super synchronous orbit, which was about 2,000 km higher than the geosynchronous transfer orbit, an elliptical orbit used to transfer between two circular orbits. This was done to save fuel in the satellite and enhance its life span.

A day after the launch, ISRO scientists began the operation of moving the satellite to its final geostationary orbit with the first orbit raising manoeuvre by firing its onboard liquid apogee motor (LAM) engine at 9.16 am for a duration of 1.08 hours.