MUMBAI: The Indian Space Research Organisation's (Isro) telecommunications satellite Insat 4A's orbit has been raised further. In the second orbit raising manoeuvre conducted at 1.24 pm on 24 December 24, the Liquid Apogee Motor (LAM) on board Insat 4A was fired for 42 minutes by commanding the satellite from Master Control Facility (MCF), Hassan.

With this LAM firing, Insat 4A perigee (closest point to the earth) has been raised to 31479 km. The apogee height remains at 36,008 km and the inclination of the orbit with respect to the equatorial plane has been reduced from 0.85 deg to the present 0.12 deg. Insat 4A now has an orbital period of 22 hours 13 minutes. The satellite will now be in the continuous radio visibility of MCF-Hassan.

Insat 4A was launched by European Ariane-5 launch vehicle on 22 December, 2005 from Kourou, French Guyana. The launch vehicle had placed Insat 4A in an orbit with a perigee (closes point to the earth) of 622 km and apogee (farthest point to earth) of 36,152 km.

The first orbit raising manoeuvre carried out from MCF, Hassan on 23 December had put the satellite in an intermediate orbit of 13733 km perigee and 36,008 km apogee.

The satellite came within the radio visibility of MCF this morning at 07.19 am and all the necessary operations like earth acquisition and gyro calibration were carried out before the second orbit raising manoeuvre was started.

The next orbit manoeuvre to place Insat 4A in near Geosynchronous Orbit is planned on 26 December, 2005. Deployment of the two solar panels and the two antennas will be carried out subsequently.