Isro to launch IRNSS-1H navigation satellite from Sriharikota at 7 pm today

The 29-hour countdown for the launch of India's eighth navigation satellite IRNSS-1H began at 2 pm on Wednesday at the Sriharikota rocket port. (Photo: PTI)
India is set to launch its eight navigation satellite IRNSS-1H from Sriharikota in Andhra Pradesh on Thursday. The countdown has begun for the launch of the IRNSS-1H satellite, weighing around 1,425 kilograms (kg), that is scheduled to take off at around 7 pm today. 

 
The satellite will be carried by the Polar Satellite Launch Vehicle (PSLV-C39).

Preparatory work related to the launch is underway, even as propellant filling operations for the four stage/engine PSLV-C39 rocket have been completed. 

 
Since 2013, the Indian Space Research Organisation (Isro) has launched seven navigation satellites. The last one was launched on April 28, 2016. Each satellite has a life span of 10 years.

The satellite, which will be launched on Thursday, will replace the IRNSS-1A satellite as its rubidium atomic clocks have failed. It may be noted, the clocks are important to provide the accurate positional data.

The Rs 1,420-crore Indian satellite navigation system NavIC consists of nine satellites-- seven in the orbit and two as substitutes. The IRNSS-1H is one of the substitute satellites, according to reports.

Each satellite has three clocks and a total of 27 clocks, including the standby satellites, were supplied by the same vendor. 
Like its predecessors, the IRNSS-1H satellite also carries two types of payloads – navigation payload and ranging payload. The payload will transmit navigation service signals to the users and they will be operating in L5-band and S-band.

The ranging payload of the IRNSS-1H satellite consists of a C-band transponder, which facilitates accurate determination of the range of the satellite. IRNSS-1H also carries corner cube retro reflectors for laser ranging.

According to ISRO, NavIC is useful for fishermen to reach the potential fishing area. Fishermen can also get alerts relating to bad weather, high waves or potential breach of international maritime boundaries.

These services are provided through a software application on a smart phone and it will help merchant ships in navigation, besides being instrumental in rescue and search operations.

In the road transport sector, the NavIC would also enable transport operators to track vehicles.

ISRO said that the navigation system will also be helpful for the railways in terms of tracking trains. Services can also be used for issuing alerts, besides facilitating location-based services, survey and alignment, along with time-synchronised services