CHENNAI: The moment of truth is here. At 12:50 pm on Thursday, India’s long cherished dream of owning an indigenous Indian Regional Navigation Satellite System (IRNSS) will be fulfilled, if the ‘work horse’ Polar Satellite Launch Vehicle (PSLV-C33) maintains its winning streak and successfully launches IRNSS-1G, seventh and the last satellite of the IRNSS constellation into the targeted Sub-Geosynchronous Transfer Orbit (Sub-GTO).
On Tuesday, 51:30 hour countdown for the launch has begun at 9:20 am in Mission Control Centre (MCC) at Sriharikota. The launch will take place from the first launch pad of Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota, said senior officials at Indian Space Research Organisation (ISRO).
It would be a culmination of 17 years of rigorous work by Indian space scientists. India took a firm decision on IRNSS in 1999 after US government refused to share GPS data that would provide vital information on Pakistani troop’s position during Kargil war.
Speaking to The New Indian Express over phone from Sriharikota, P Kunhikrishnan, director, SDSC, Sriharikota said the 44.4 metre tall IRNSS-1G has a lift-off mass of 1,431 kg. “The countdown is progressing smoothly and we are updating the details on the website”, he said.
As in the previous six launches the IRNSS satellites, PSLV-C33 will use ‘XL’ version of PSLV equipped with six strap-ons, each carrying 12 tons of propellant, an Isro official said.
Out of seven IRNSS constellation, three satellites will be located in suitable orbital slots in the geostationary orbit and the remaining four will be located in geosynchronous orbits with the required inclination and equatorial crossings in two different planes.
All the satellites of the constellation are configured identically. The satellites are configured with I-1K Bus to be compatible for launch on-board PSLV. Though the full system comprises nine satellites — seven in orbit and two on the ground as stand-by, ISRO is yet to take a decision on stand-by options, the director said.
The ‘value for money’ ISRO scientists had earlier said that IRNSS would be operational with just 4 satellites, but for accuracy reasons a constellation of seven was designed.
To a query, Kunhikrishnan said the ISRO headquarters will take a decision on when the IRNSS services will be rolled-out. “As of now, our focus is on ensuring the successful launch of IRNSS-1G, which is a historical moment for the national space agency,” he added.
It can be learnt that ISRO has launched the first dedication navigation satellite, IRNSS-1A in July 2013, the second in April 2014, the third on October 2014, the fourth in March 2015, and the fifth and sixth on January 20 and March 10 this year.