The Indian Space Research Organisation (ISRO) is looking forward to the liftoff of its Polar Satellite Launch Vehicle PSLV-C24 from Sriharikota at 5.14 p.m. today.

After more than 19 minutes of flight, if the PSLV-C24 puts India’s navigation satellite, called the Indian Regional Navigation Satellite System (IRNSS-1B), into a perfect orbit, applause will echo across the Mission Control Centre. More so, because it will be the 25th consecutive successful launch of a PSLV, the ISRO’s trusty workhorse.

This launch vehicle is the PSLV’s XL version, armed with more powerful strap-on booster motors than in the standard PSLV, which will put the 1,432-kg IRNSS-1B into its orbit.

The IRNSS-1B is India’s second dedicated navigation satellite. The first, IRNSS-1A, was put into orbit on July 1 last year. All the seven satellites, which form the IRNSS, will be in orbit by 2016.

“The countdown is proceeding as per the timeline, without any issues,” said M.Y.S. Prasad, Director, Satish Dhawan Space Centre, Sriharikota, on Thursday.

The countdown, which will last 58 hours and a half, began at 6.44 a.m. on April 2. By Thursday afternoon, the PSLV-C24’s fourth stage was accurately filled with liquid propellants and the lower stage control systems with solid propellants.

“From 11 p.m. on Thursday till the early morning of Friday, we will fill the rocket’s second stage with more than 41 tonnes of liquid propellants. Then, other operations such as filling the launch vehicle with pressurised gas will be done,” said Dr. Prasad. During the countdown’s final phase, the rocket’s electronic systems will be tested.