With the PSLV- C38 mission successfully deploying 31 satellites in orbit, engineers at the ISRO were trying out a series of manoeuvres for multiple restart and deorbiting of the fourth stage (PS4) of the rocket.

The rocket engines are to be shut down and reignited thrice, in a bid to master the technique that will enable ISRO to inject satellites into different orbits in a single launch.

Fifty-eight minutes after the rocket thundered off from the Satish Dhawan spaceport at Sriharikotta and ejected the 31 satellites into orbit, the twin engines of PS4 were first restarted. The process was repeated 46 minutes later. The third restart was scheduled about midnight after the PS4 completed nine orbits.

“With the first and second restarts, the PS4 orbit was brought down from 505 km to 350 km,” K. Sivan, Director, Vikram Sarabhai Space Centre told The Hindu from SHAR. The third reignition of the engines would involve only a change in inclination. He said all 31 satellites “are in good health. Cartosat has deployed its solar panels.”

ISRO engineers are upbeat over the success of the PSLV- C38 mission, coming as it does, close on the heels of two successful GSLV launches. On May 5, a GSLV Mark 2 launcher injected the GSAT-9 satellite into orbit while on June 5, the GSLV Mark3, the heaviest rocket made by ISRO, placed the GSAT-19 in orbit.