The 29-hour countdown for the launch of India's eighth navigation satellite IRNSS-1H began at 2 p.m. on Wednesday at the Sriharikota rocket port, around 80 km from here, officials said.
The 1,425-kg satellite - part of Indian Regional Navigation Satellite System (IRNSS) - will be carried by Polar Satellite Launch Vehicle (PSLV) rocket XL variant that will blast off on Thursday evening at around 7 pm, said an official of the Indian Space Research Organisation.
This will be the eighth IRNSS satellite and will be a replacement for IRNSS-1A as its rubidium atomic clocks have failed. The atomic clocks are important to provide the accurate positional data.
Simply put, the IRNSS or NavIC (Navigation with Indian Constellation) is similar to the US-owned GPS.
The Rs 1,420-crore Indian satellite navigation system NavIC consists of nine satellites - seven in orbit and two as substitutes. One of the substitutes is the IRNSS-1H.
Each satellite has three clocks and a total of 27 clocks for the navigation satellite system (including the standby satellites) were supplied by the same vendor. The clocks are important to provide precise locational data.