Friday, December 23 2005 14:03 Hrs (IST) - World Time -

Bangalore: In the first critical orbit-raising operations today, INSAT-4A was placed in intermediate orbit by Indian space scientists, and all systems on board the spacecraft are functioning normally, according to Indian Space Research Organisation.

INSAT-4A, equipped with high-powered 12 ku-band and 12-c band transponders, was successfully launched by an Ariane rocket from the Kourou spaceport in French Guiana yesterday.

The Ariane 5 generic vehicle of European Space consortium Arianespace, the launch services provider, had placed India's fourth generation telecommunications satellite in an orbit with a perigee (closest point to the earth) of 622 km and apogee (farthest point to earth) of 36,152 km.

Bangalore-headquartered ISRO's Master Control Facility at Hassan in Karnataka acquired the first signals at 04:32 am yesterday, and conducted initial phase operations on the spacecraft. ISRO said the first critical orbit-raisign manoeuvre was conducted at 06.24 am today when the 440 Newton Liquid Apogee Motor (LAM) on board the satellite was fired for 85 minutes by commanding the satellite from MCF.

"With this LAM firing, INSAT-4A perigee has been raised to 13,733 km", ISRO said in a statement. The apogee is 36,008 km and the inclination of the orbit with respect to the equatorial plane has been reduced from four degree at the time of launch to 0.85 degree now. The orbital period is 15 hours, 16 minutes.

Further orbit raising manoeuvres are planned in the next few days, India's space agency said. INSAT-4A will be manoeuvred to its final geo stationary orbit, which is 36,000 km above the equator.