Bengaluru: 29-hour countdown for the launch of the latest navigation satellite the IRNSS-1H, which will join the Indian Regional Navigation Satellite System (IRNSS) constellation, started at 2pm, said The Indian Space Research Organisation (ISRO), said on Wednesday.
The satellite, which will be launched from the second launch pad of the Satish Dhawan Space Centre in Sriharikota on Thursday, will serve as a replacement to the IRNSS-1A, all three of whose atomic clocks have failed.
The 1,425-kg satellite will be launched aboard PSLV-C39, which is scheduled to take off at 7pm on Thursday.
ISRO said that the Mission Readiness Review (MRR) committee and Launch Authorisation Board (LAB) gave the nod for the countdown on Tuesday. The first satellite as part of the IRNSS was launched on July 1, 2013 and the next one (IRNSS-1I) is scheduled for an April 2018 launch.
The satellite will be launched into a sub Geosynchronous Transfer Orbit (sub-GTO) with a 284 km perigee (nearest point to Earth) and 20,650 km apogee (farthest point to Earth).
After injection into this preliminary orbit, the two solar panels of IRNSS-1H are automatically deployed and the Master Control Facility (MCF) at Hassan will take control of the satellite and perform the initial orbit raising manoeuvres, and finally place it in its designated slot.
Once fully functional, the IRNSS will be useful for the railways, survey and alignment, providing location-based services among other things. The Indian Air Force (IAF), will also be replacing GPS with IRNSS on its fighter planes. It will also aid disaster management, vehicle tracking and provide other services.