Chandrayaan-3 completes 4th orbit-raising manoeuvre

INTERNATIONAL DESK: India’s Chandrayaan-3 spacecraft moved into a new, higher, orbit around the Earth on Thursday after the successful completion of the fourth orbit-raising manoeuvre, the Indian Space Research Organisation (ISRO) said.

“India celebrates the International Moon Day 2023 by propelling Chandrayaan-3 a step closer to the moon. The fourth orbit raising manoeuvre (Earth-bound perigee firing) is performed successfully from ISTRAC/ISRO (ISRO Telemetry, Tracking and Command Network), Bengaluru,” the ISRO tweeted.

Chandrayaan-3, which is slated to make a soft landing on the Moon’s surface next month, is currently going around the Earth in elliptical orbits, sequentially raising the heights of these orbits.

The spacecraft is supposed to make five such orbit-raising manoeuvres to continuously move into higher and higher orbits before beginning to move directly towards the moon. Once there, it would do similar exercises to slowly get into lower and lower orbits around the moon before eventually reaching a circular orbit about 100 km from the lunar surface. It is from this circular orbit that the final descent to the Moon’s surface would take place on August 23 or 24.

Chandrayaan-3 is taking a circuitous route in its journey, rather than travelling directly to the Moon, in order to economise the entire travel. A direct trip to the Moon, which takes about four days, would require much heavier rockets, and huge amounts of fuel, to leave the space further into space. Instead, Chandrayaan-3 was taken to a near Earth orbit, from where it has been utilising the force of gravity to gain momentum, and then fire thrusters to accelerate and reach a higher orbit.

This process involves burning of a much lesser amount of fuel but takes a longer time to reach the Moon.

The fifth and final orbit-raising manoeuvre in the earth orbit is scheduled to take place between 2 pm and 3 pm on July 25, the ISRO stated.