The GSAT-6A communications satellite sporting a new 6m communications antenna to deliver mobile S-band communications to India was successfully launched into a geostationary transfer orbit (GTO) using a GSLV 2/CUSP rocket. Lift off from the Sriharikota launch site was at 1126 GMT on 29 March.
Update on 3 April 2018: It was subsequently revealed that all contact with the spacecraft was lost on 31 March 2018 during the second firing of its own Liquid Apogee Motor to raise the satellite into GEO. A power failure is suspected. The satellite is currently in a 36,368 x 25,981km orbit at 3.3 degrees to the equator. The planned third firing of the Liquid Apogee Motor, which has been prevented by the loss of communications, was to have fully circularised the orbit.
The 2,140kg GSAT-6A spacecraft uses the I-2K bus platform built by ISRO (Indian Space Research Organisation). The satellite is owned by ISRO. About 90% of satellite’s S-band payload was originally to have been made available to the private firm, Devas Multimedia, but that deal was later cancelled following a political scandal.
The spacecraft was not believed to have been insured on the international market, but may have been insured on the Indian local insurance market to a value of circa US$40-50 million.
ISRO did at least have the consolation that on this flight the GSLV 2 rocket itself worked well given its past unreliability. This launch employed a new slightly more powerful version of the Vikas – the High Thrust Vikas Engine – on the rocket’s second stage. This new engine will also be used by the liquid fuel powered boosters on later GSLV 2 flights. The second stage engine steering also used new electromechanical actuators replacing hydraulic versions.
The upper stage of the rocket was fired to the depletion of its liquid oxygen. This allowed a slightly raised apogee which is more efficient for inclination removal. The Geosynchronous Transfer Orbit (GTO) achieved was 36,508 x 149km at 20.7 degrees inclination.
GSAT-6A is launched by GSLV 2/CUSP. Courtesy: ISRO
