GSAT 6A was launched in March 2018 and was meant to support military communications in hostile regions using handy ground terminals.
India's heaviest communication satellite, GSAT-11 weighs 5,854 kg.
For the first time in history, ISRO said 2 launches will be planned every month from February 2019.
If the GSAT-6A satellite does not respond by 2019, it will be declared "dead", the ISRO chairman added.
“After a thorough check and additional tests, it was found fit for launch,” an official said.
GSAT-11 was designed, assembled and integrated by the ISRO, and will have an estimated lift-off mass of 5,870 kg. It was planned to be launched mid May.
For ISRO, power system failure in its satellites was not new. It happened with communication satellites like INSAT-1A, INSAT-1C and INSAT-2D.
ISRO is working overtime to restore a communication link with GSAT-6A satellite, says chairman K Sivan
Complementing the GSAT-6 that was launched earlier in 2015, the GSAT-6A was to help provide the technologies for point-to-point communication.
A day after GSAT-6A, India's latest communication satellite, went incommunicado in space, ISRO officials said that they were working to restore the link with it
ISRO confirms loss of contact with GSAT-6A, after India’s largest communications satellite stops sending data
Four minutes after an orbit raising manoeuvre (the second of three such manoeuvres) at 10.51 am on Saturday, the satellite stopped sending data.
India on Thursday successfully launched the GSAT-6A satellite that would provide mobile communication facilities
The two satellites 90 percent transponders were to be leased to Devas Multimedia Ltd by ISRO's commercial arm Antrix Corporation.
All stages of the rocket were successfully executed during the launch and the payload fairing containing the GSAT-6A was separated as per calculations.
ISRO GSAT-6A communications satellite to launch today aboard the GSLV-F08 rocket: All you need to know
The S-band GSAT-6A communication satellite will be India's second after launching the GSAT-6 back in August 2015.
CBI on Wednesday carried out searches after registering a case to probe an alleged Rs 578-crore "wrongful" gain to a private multi-media company Devas by Antrix, the commercial arm of ISRO.