The 27 hour countdown began on Wednesday for the launch of ISROs GSLV-F08 mission carrying the GSAT-6A communication satellite from the space port of Sriharikota, about 110 kms from here. The countdown for the mission to be launched Thursday started at 13.56 hours following clearance from the Mission Readiness Review committee and Launch Authorisation Board, ISRO said. The Launch of GSLV-F08, planned from the second launch pad in Satish Dhawan Space Centre, Sriharikota at 16.56 hours on Thursday marks the 12th flight of Geosynchronous Satellite Launch Vehicle GSLV-F08 and sixth flight with indigenous cryogenic upper stage. GSAT-6A, is similar to GSAT-6, a high power S-band communication satellite built on I-2K satellite bus with a mission life of about ten years, it said. A key feature of the satellite is providing mobile communication to India through multi beam coverage facility.