Bengaluru: The 29-hour countdown for the Thursday evening launch of India’s navigation satellite IRNSS-1H using the rocket Polar Satellite Launch Vehicle (PSLV) will begin on Wednesday, ISRO said on Tuesday. According to Indian Space Research Organisation (ISRO), the Mission Readiness Review (MRR) committee and Launch Authorisation Board (LAB) have cleared the 29-hour countdown to begin at 2 p.m. 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 .
“Such failures have occurred even in Russia’s Glonass and a similar programme of the European Space Agency,” an Isro official said. 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.
The 1.4-tonne satellite will be launched from the state-run Indian Space Research Organisation’s (ISRO) spaceport at the Satish Dhawan Space Centre (SDSC) in Sriharikota in Andhra Pradesh, about 80 km northeast of Chennai. The launch will take place from the second launch pad of Satish Dhawan Space Centre (SDSC) SHAR.