Satellite launch unsuccessful: ISRO
Satellite got stuck in the fourth stage of the Polar Satellite Launch Vehicle - C39

In a setback, India's mission to launch its eighth navigation satellite where the private sector was involved for the first time in the assembly of its spacecraft failed on Thursday following a technical snag after a perfect lift off of its polar rocket.

Describing the failed mission as a 'mishap', ISRO Chairman Kiran Kumar said the heat shield did not separate for the IRNSS-1H, a backup navigation satellite, to be put into orbit in the final leg of the launch sequence. As a result, the satellite got stuck in the fourth stage of the Polar Satellite Launch Vehicle--PSLV-C39.

"While all the systems of the launch vehicle performed extremely well, we had a mishap," said the chief of the Indian Space Research Organisation (ISRO), shortly after the satellite failed to  separate as scheduled about 20 minutes after the lift-off.

The eighth satellite was a back-up navigation satellite for IRNSS-1A, one of the seven satellites in the constellation, as its three rubidium atomic clocks on board had stopped functioning.

For the first time, the private sector has been actively involved in assembling and testing of a satellite unlike earlier where its role was limited to supplying components.

Thursday's setback is considered a rare failure in India's space mission involving the PSLV, dubbed as ISRO's workhorse, which has had a time-tested record of 39 consecutive successful launches, ever since its maiden flight failed 24 years ago.

Thursday's PSLV launch was the third this year with everything appearing normal from the lift-off at 7 pm till the rocket reached the fourth stage where it is supposed to inject the satellite into orbit.

"We are looking into the details of what has happened and we will  do the analysis and subsequently come back with the details," Kumar later told reporters.

"Because the heat shield is not separated, the satellite remainins inside the fourth stage and even satellite separation also we could see from the camera images that the satellite is moving inside the enclosure," Kumar said.

Earlier, at the end of the 29-hour countdown that began on Wednesday, the 44-metre tall PSLV-C39 lifted off majestically at the scheduled time of 7 pm from the second launch pad of the Satish Dhawan Space Centre at this spaceport, about 100 km from Chennai.

ISRO had earlier launched seven satellites - IRNSS-1G on April 28, 2016, IRNSS-1F (March 10, 2016), IRNSS-1E (January 20, 2016), IRNSS-1D (March 28, 2015), IRNSS-1C (October 16, 2014), IRNSS-1B (April 4, 2014) and IRNSS-1A on July 1, 2013.

According to ISRO, the total cost of all the seven satellites was estimated at Rs 1,420 crore.

The Indian Regional Navigation Satellite System (IRNSS) is an independent regional navigation satellite system developed by India on par with US-based GPS.

Russia has 'Glonass' while 'Galileo' is by Europe. These satellites offer services like terrestrial and marine navigation, disaster management, vehicle tracking and fleet management, navigation aide for hikers and travellers, visual and voice navigation for drivers.

The NavIC system has many uses including for fishermen, guiding merchant ships to navigate, tracking of railway movement and alerting road users near unmanned level crossings.