‘Missing’ GSAT-6A: No quick fix to the problem, say ISRO scientists

CHENNAI: With each passing day, the hope of reviving military-grade communication satellite GSAT-6A is slowly fading. The Indian Space Research Organisation’s (ISRO) struggle to communicate with the missing satellite enters the fourth day and the scientists involved in the ongoing recovery efforts say, “there is no quick solution to the problem.”A top ISRO official told Express on the condition of anonymity that the space agency has a realistic chance of re-establishing the communication link only twice in day as the satellite’s orbit is currently about 13 hours. 

“Our orbit itself is about 12 to 13 hours, which means you can do only once-in-12-hour orbit measurement. The skin mode radar that we have should measure the satellite nearest point and do the measurement for transmitting the ground signal. All this takes time. We don’t have a quick solution. That is the difficulty,” the official said explaining the extraordinary efforts being made.Further, scientists say there were ample instances in the past across the space-faring nations, where the ‘Earth Lock’ or the communication link with the satellite is lost immediately or a few days after the launch and re-established again. “All these show that it’s possible and we should not stop trying,” another official said. 

Meanwhile, sources said the probe panel headed by former ISRO Satellite Centre (ISAC) director PS Goel was given access to full data sets and has begun investigation into what went wrong. ISRO has also deployed all its global network of ground stations to detect the lost satellite. ISRO Telemetry, Tracking and Command Network (ISTRAC) with full redundancy multi-mission Spacecraft Control Centre is working round the clock along with Mission Control Facility to improve the chances of satellite recovery. 

ISTRAC global network stations are located in Mauritius, Indonesia, Norway, Antarctica, Panama, Vietnam and Russia. On March 29, the Indian rocket Geosynchronous Satellite Launch Vehicle (GSLV) slung GSAT-6A in its intended orbit. From there the satellite was to be taken up further to its orbital slot by firing its onboard motors. The first orbit raising operation was successfully carried out by firing the onboard motors for around 36 minutes on March 30 morning. 

The second orbit-raising operation of GSAT-6A satellite was also successful as its motors were fired for about 53 minutes on March 31. After that, the communication link got snapped. The GSAT-6A is the twin of GSAT-6, which has been orbiting since August 2015. The satellite was to provide communication through five spot beams in S-band and a national beam in C-band for strategic users. The satellite has one of the largest Unfurlable Antennas of 6 m diameter realised by ISRO and the 2066-kg spacecraft is facing a potential danger of turning into a space debris.