Indian Space Research Organisation (ISRO) has successfully disposed of the communication satellite GSAT-12 in a post-mission disposal (PMD) operation. According to ISRO, the operation was completed on March 23, 2023.
GSAT-12 is the twenty-third Geosynchronous Earth Orbital (GEO) satellite to undergo PMD before decommissioning, and it carried 12 extended C band transponders. It was launched on July 15, 2011, and served for more than a decade. After the launch of its replacement satellite CMS-01 in 2020, it was relocated to 47.96 degrees E longitude.
The GEO regime is one of the most populated and highly utilized regions. To minimize space debris risks, internationally accepted space debris mitigation guidelines by the UN and International Association of Drilling Contractors: IADC recommend disposing of an object away from the GEO region at its end-of-life. The recommended practice is to re-orbit the object to a nearly circular "graveyard" orbit above the GEO region so that the orbit would not decay back into the GEO-protected zone under the influence of perturbation forces within another 100 years.
According to ISRO, for GSAT-12, the required minimum raise in perigee altitude was estimated to be 261 km. As a result of meticulous operations management by the Master Control Facility (MCF), the available fuel of GSAT-12 was more than sufficient to meet this goal. A series of seven maneuvers were carried out to raise the orbit above the GEO altitude of 35,786 km. The first maneuver on March 16, 2023, was a shorter burn to circularize the orbit, followed by another six burns of typically 150 seconds duration.
Four inclination changing maneuvers of GSAT-12 were carried out during March 20-22 to spend the remaining propellant. On March 23, the final passivation maneuver was carried out to vent out the remaining fuel by firing the oppositely mounted thrusters, cancelling the net thrust without affecting the orbit.
As part of electrical passivation, all rotating mechanisms such as the momentum wheels, reaction wheels, and gyros were turned off, batteries were disconnected from the solar panels and discharged. Finally, the transmitters were switched off to avoid any potential RF interference. The passivation activities were completed on March 23, 2023.
All operations were conducted by MCF, Hassan, in coordination with U R Rao Satellite Centre, SATCOM Programme Office, and IS4OM (ISRO System for Safe and Sustainable Space Operations Management).
Important News Tags for Readers
About the Disposal of GSAT-12 Satellite