The 8th navigation satellite IRNSS-1I will be the replacement for the 1,425 kg IRNSS-1H satellite which was to be slung into the polar orbit at 507 km above the Earth. IRNSS-1H launched on 31 August 2017 was expected to replace IRNSS-1A, the first of the seven constellation satellites, which was rendered ineffective after its three rubidium atomic clocks failed. Unfortunately, IRNSS-1H satellite was unable to eject out of the PSLV rocket in its intended orbit. Even about 20 minutes after its launch, the heat shield failed to separate which otherwise should have separated after 3 minutes. After waiting for 19 minutes for the heat shield to separate, the ISRO scientists declared the mission unsuccessful.

The ISRO’s Polar Satellite Vehicle (PSLV-C41) carrying IRNSS-1I is scheduled to take off from the launch pad at 4:04 am. The launch will mark PSLV’s 20th flight with the ‘XL’ configuration.

Picture provided by ISRO