Understanding the reason behind GSAT-6A satellite’s failure

On 27 August 2015, the Indian Space Research Organization had successfully launched GSAT-6, a member of the INSAT series, a communication satellite to offer a Satellite Digital Multimedia Broadcasting(S-DMB) services at the cost of ₹ 269 Crore. 

Almost three years later, ISRO successfully launched GSLV-08 carrying the successor satellite GSAT-6A on 29 March 2018 at the cost of ₹ 147 Crore. With the mission life of 10 years, it was envisioned to support the GSAT-6 satellite and better the communication system of the country. Both high power S-Band satellites were used in the communication system to make it a two-way communication channel. The S-Band antenna in GSAT-6A was made three times broader than its predecessor satellite to make it more capacitive and to provide mobile communication in the country through multi-beam coverage. The satellite was also designed to provide technology development platform that could be useful in satellite-based mobile communication applications. It was also to be used to provide services to the Indian Armed Forces.

On 30 March 2018, The First orbit raising maneuver for GSAT-6A was done successfully by firing the Liquid Apogee Motor. The second orbit raising maneuver was carried out on 31 March 2018. Shortly after that, while the satellite was on its way for the third and final orbit maneuver raising process on 1 April 2018, the ground station lost communication with it.

What went wrong with the satellite?

Before analyzing what might have gone amiss, it is necessary to understand how the satellites are placed into the desired orbit. A launch operation of any satellite consists of three initial stages during which it is raised to different heights by the launch vehicle and then placed in the geosynchronous transfer orbit. It is an elliptical orbit into which a satellite is initially injected before it is transferred into a geosynchronous orbit (GSO) where it is positioned at a fixed longitude. During each the stages, a part of rocket disengages after its designated role is completed. Then the satellite moves towards its desired orbit. 

The GSAT-6A was first maneuvered to the elliptical orbit followed by second orbit-raising operation. It was after this and during the final process that the communication with the satellite was lost. It has been hypothesized that the failure to maintain and re-establish the connection occurred due to a flaw outside the launch vehicle, presumably from a short circuit or a power glitch within the satellite itself.

Though the final word has not been given, ISRO is still in the process of establishing communication with GSAT-6A. Though the loss of GSAT-6A jolted the organization, the tragedy is far from stopping ISRO from launching its navigation satellite IRNSS-1I on April 12 and putting another feather in its cap. 

Picture provided by ISRO