GSAT-6A was a communication satellite launched by the Indian Space Research Organisation (ISRO) It featured a 6-metre (20 ft) unfurlable S-band antenna similar to the one used on GSAT-6.[1] Around 17 minutes after lift-off, the three stage GSLV Mk.II rocket flying on GSLV F08 mission successfully injected the satellite into a geosynchronous transfer orbit.[3] Due to power failure during its orbit raising burns the communication was lost with GSAT-6A[4][5] before it could reach its final circular geostationary orbit (GSO).
History
GSAT-6A was launched to complement GSAT-6 satellite which was launched in August 2015 by ISRO. The cost of building GSAT-6A was around ₹270 crore.[6][7][8] GSAT-6A was to provide mobile communication services to the Indian Armed Forces.[9]
Launch
GSLV F08 launch from SLP
GSLV-F08 carrying GSAT-6A spacecraft was launched from Second Launch Pad of Satish Dhawan Space Centre on 29 March 2018, 11:26 UTC and after flight of 17 minutes 45 seconds,[10] placed GSAT-6A into its planned geostationary transfer orbit with 36,692.5 kilometres (22,799.7 mi) apogee, 169.4 kilometres (105.3 mi) perigee and orbital inclination of 20.64°. GSAT-6A spacecraft deployed its solar array after separation from CUS and established contact with ground station.[11]
On GSLV-F08, a High Thrust Vikas engine (HTVE) was inducted on second stage (GS2) of GSLV with 6% higher thrust than before.[12][13] The improved engine increased the payload capability of the vehicle.[10] The electrohydraulic actuation system on second stage was also replaced with simpler and robust electromechanical system.[13] The Cryogenic Upper Stage of GSLV F08 performed a burn to depletion for the first time. Officials said any improvement done to the vehicle would be incorporated into GSLV's future missions.[10]
Loss of communication
The first orbit raising maneuver for GSAT-6A was carried out as planned on 30 March 2018 by firing the Liquid Apogee Motor (LAM) for 2188 seconds from 09:22 AM IST. The second orbit raising maneuver was carried out at 10:00 AM on 31 March 2018. As the satellite was on-course for its third and final orbit raising maneuver on 1 April 2018, communication with it was lost and the spacecraft was temporarily untraceable.[14][15][5] After regaining its track,[16] efforts to re-establish communication with the satellite could not succeed.[17][18] Power system malfunction was suspected to be the reason behind loss of contact.[19][20][21]
Satellite replacement
ISRO will launch GSAT-32 satellite as replacement for GSAT-6A.[22]
^"Chandrayaan-2 to be launched in January-March window in 2019". 12 August 2018. Retrieved 1 November 2019. Asked about GSAT 6A, with which communication had been lost after its launch in March 31 this year, he said ISRO has not given up hope and was still trying to establish radar contact with the satellite. "We have not given up hope. We will wait till a year," he said when asked how much time ISRO would take to announce that the GSAT 6A was a failed mission.
^D.s, Madhumathi (2018-08-11). "We averted a possible debacle: ISRO chairman". The Hindu. ISSN0971-751X. Retrieved 2022-02-03. GSAT-11 had the same set of power system configuration that two older satellites had. RISAT-1 died prematurely and GSAT-6A lost communication contact soon after launch on March 29 because of suspected power system failure, harnesses etc.
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
