The Indian Space Research Organisation (ISRO) announced Sunday that it has lost communication with its GSAT-6A satellite launched on board the GSLV F08 rocket on March 29. The loss of contact was reported a day after executing the satellite’s second orbit raising manoeuvre.
“When the satellite was on course to normal operating configuration for the third and final firing, scheduled for April 1, 2018, communication from the satellite was lost. Efforts are underway to establish the link with the satellite,’’ the space agency said in a statement Sunday.
ISRO had earlier not reported on the status of the second orbit raising manoeuvre on the GSAT-6A, which was to be carried out Saturday after the launch and first orbit raising manoeuvre on Thursday and Friday.
“The second orbit raising operation of GSAT-6A satellite has been successfully carried out by LAM Engine firing for about 53 minutes on March 31, 2018, in the morning,’’ ISRO said on Sunday without explaining the delay in providing the update. Sources in ISRO said the delay was due to key personnel involved with the updates falling ill.
On Sunday, the space agency reported the successful execution of the second orbit raising manoeuvre but also reported the loss of communication with the satellite indicating that this has affected the third orbit raising manoeuvre which is needed to make the satellite operational.
The GSAT-6A was originally intended to be launched by ISRO for the Bengaluru-based startup Devas Multimedia but the satellite, which uses the S-band and C-band for communications, was diverted for use by defence forces and “security purposes’’ after the Devas Multimedia deal was annulled by the UPA government in 2011 over alleged irregularities in the deal.
“We cannot say what exactly has gone wrong with the communication link to the satellite. It could be one of multiple reasons. Our engineers are working overtime to establish contact with the spacecraft,’’ said sources in ISRO.
“Everything was going perfectly well till March 31 but we lost communication after the second manoeuvre. We are trying to restore communication. We cannot say that the satellite is lost as yet,’’ the ISRO sources said.
The GSAT-6A was launched on board the GSLV F08, which is an upgraded version of ISRO’s heavy-lift GSLV Mk II rocket on March 29 from the Satish Dhawan Space Centre at Sriharikota. The launch went off well and the communication satellite was successfully inserted into transit orbit.
“The first orbit raising operation of GSAT-6A Satellite has been successfully carried out by LAM Engine firing for 2,188 seconds from 09:22hr IST on March 30, 2018,’’ ISRO reported on Friday.
“Orbit determination results from this LAM firing are: apogee x perigee height was changed to 36412 km x 5054 km. Inclination is 11.93 deg. Orbital period is 12hr 45min,’’ ISRO said.
The orbital raising manoeuvres are carried out by firing engines on board the spacecraft through commands issued from ground stations. The loss of communications prevents the transfer of commands from earth to the spacecraft to fire the engines to change its orbit.
This has happened in the past after satellites were launched by ISRO. In February 2017, shortly after ISRO launched two experimental Indian nano satellites INS-1A and INS-1B weighing 8.4 kg and 9.7 kg “some difficulties in signals” between the satellites and ground stations were reported a few days after the launch. The satellites were reported to have been stabilised later.
“There were some initial difficulties because it was the first time we were managing three satellites at the same time. After the initial hiccups, things have settled and the satellites are under our control,” director of ISRO’s satellite centre Mylaswamy Annadurai had then said.