Isro starts count-down for tomorrow’s IRNSS-1D launch

The Indian Space Research Organisation (Isro) is all set to launch its fourth navigational satellite IRNSS-1D tomorrow (28 March), which would be followed by two more launches this year and a third next year, completing the seven-satellite regional navigational system.

Isro will use its Polar Satellite Launch Vehicle, in its twenty-seventh flight (PSLV-C27) to launch IRNSS-1D, the fourth satellite of the Indian Regional Navigation Satellite System (IRNSS).

The launch will take place from the second launch pad (SLP) of Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota. As in the previous three launches of IRNSS satellites, PSLV-C27 will use the 'XL' version of PSLV.

''PSLV-C27/IRNSS-1D countdown operations are progressing normally. Propellant filling operation of second stage (PS2) of PSLV-C27 will be initiated by midnight of today,'' according to an Isro release.

The IRNSS system is unique as it consists only seven satellites while other systems have more than 20 satellites. While other systems are global, Indian system is of regional in nature.

However, the Indian Regional Navigational Satellite System (IRNSS), when fully operational, can replace the US global positioning system (GPS), Isro officials claim.

The fully operational system is expected to provide accurate position information service to users across the country and the region, extending up to an area of 1,500 km.

"Now, we are getting ready to launch IRNSS-1D - the fourth among seven satellites in the Indian Regional Navigation Satellite System (IRNSS) series - on Saturday," Isro chairman V S Kiran Kumar said on Thursday. He held a review meeting with scientists of Isro in Bangalore, including those from Vikram Sarabhai Space Centre (VSSC), Liquid Propulsion Systems Centre (LPSC) and Isro Inertial Systems Unit (IISU) on Thursday.

Isro officials, meanwhile, denied any diversion of focus or delay in the operationalisation of navigation satellite system.

According to officials, the seventh and the last one of the Indian Regional Navigation Satellite System (IRNSS) in all probability would go up early part of 2016.

Full navigation services are expected to be offered from mid 2016 onwards, according to the officials.