The Indian Space Research Organisation (ISRO) has successfully carried out the fourth and final orbit raising operations of navigation satellite, IRNSS-1I, the space agency has said. The orbit raising operation took place at 9.05 pm on Sunday, the ISRO said.
The achieved perigee height (nearest point to the earth) is 35,462.9 km and apogee height (farthest point to the earth) is 35,737.8 km. The IRNSS-1I was launched on April 12. After a flight lasting about 19 minutes, the Polar Satellite Launch Vehicle (PSLV) achieved a Sub Geosynchronous Transfer Orbit with a perigee of 281.5 km and an apogee of 20,730 km inclined at an angle of 19.2 degree to the equator. At that point, the IRNSS-1I got separated from the rocket.
Following that ISRO carried out four orbit raising operations on April 13 (first and second), April 14 (third operation) and April 15. However, the ISRO did not provide any information for how many minutes the satellites’ onboard motors were fired for raising the orbit.
The successful launch of the IRNSS-1I means it will be able to replace IRNSS-1A. Part of India’s seven navigation satellites, a constellation designated NavIC, it was rendered ineffective after the failure of its three rubidium atomic clocks. The launch was ISRO’s second attempt at sending a replacement satellite. Previously, a PSLV mission carrying the IRNSS-1H last August failed, as the heat shield covering the satellite failed to separate.