Isro to Launch Fourth Navigational Satellite IRNSS-1D on Saturday

India's fourth navigation satellite will be launched on March 28 evening, the Indian space agency said on Monday.

According to Indian Space Research Organisation (Isro), the Indian rocket - Polar Satellite Launch Vehicle (PSLV-XL) - will blast off with the fourth satellite of the Indian Regional Navigation Satellite System (IRNSS) at 5.19 p.m. on March 28.

The 1,425 kg satellite is called IRNSS-1D and will be the first satellite to be put into orbit by an Indian rocket in 2015.

"The rocket has been moved to the launch pad or the umbilical tower. The rocket will be fixed to the umbilical tower," M.Y.S. Prasad, director of the Satish Dhawan Space Centre, told IANS over phone from Sriharikota.

India's only rocket port is located at Sriharikota in Andhra Pradesh around 80km from Chennai.

According to Prasad, after the rocket is connected to the umbilical tower system, checks would be carried out including full rocket and satellite checks.

Originally Isro had planned to launch the IRNSS-1D satellite on March 9.

But on March 4, Isro deferred the launch after it found that one of the telemetry transmitters in the IRNSS-1D was not working properly.

India has so far launched three regional navigational satellites as part of a constellation of seven satellites to provide accurate position information service to users across the country and the region, extending up to an area of 1,500km.

Though the full system comprises nine satellites - seven in orbit and two on the ground as stand-by - the navigation services could be made operational with four satellites, Isro officials had said.

Each satellite costs around Rs. 150 crores and the PSLV-XL version rocket costs around Rs. 130 crores. The seven rockets would involve an outlay of around Rs. 910 crores.

The entire IRNSS constellation of seven satellites is planned to be completed this year itself.

The first satellite IRNSS-1A was launched in July 2013, the second IRNSS-1B in April 2014 and the third on October 16, 2014.

Once the regional navigation system is in place, India need not be dependent on other platforms.

Meanwhile European space agency Arianespace is also getting ready to launch two Galileo satellites on March 27.

The two satellites would be launched jointly by a Soyuz rocket blasting off from French Guyana.

According to Arianespace, the Galileo programme is Europe's initiative for satellite navigation. Providing a highly accurate global positioning system under civilian control, it would consist of 30 satellites in total, along with European control centres and a worldwide network of sensor and uplink stations.