India’s ambitious third Moon mission’s spacecraft Chandrayaan-3 underwent another manoeuvre, bringing it even closer to the Lunar surface, ISRO said. The ISRO headquarter here said the spacecraft has now achieved a “near-circular orbit” around the moon.
After its launch on 14th July 2023, Chandrayaan-3 enter into the lunar orbit on 5th August 2023, following which two orbit reduction manoeuvres were carried out on 6th and 9th August 2023.
ISRO said in a tweet :
"Orbit circularisation phase commences. Precise manoeuvre performed today has achieved a near-circular orbit of 150 km x 177 km,".
The next operation is plan for 16th August 2023, around 8:30 am, ISRO said.
As the mission progresses, a series of manoeuvres are being conduct by ISRO to gradually reduce Chandrayaan-3’s orbit and position it over the lunar poles.
According to ISRO sources, one more manoeuvre will be perform on the spacecraft on 16th August 2023 to reach 100 km orbit, following which the landing module, comprising the lander and rover will break away from the propulsion module.
After this, the lander is expect to undergo a “deboost” (the process of slowing down) and make a soft landing on the south polar region of the Moon on 23rd August 2023.
Last week, ISRO Chairman S Somnath said the most critical part of the landing is the process of bringing the velocity of the lander from 30 km height to the final landing, and that the ability to transfer the spacecraft from horizontal to vertical direction is the “trick we have to play” here.
S Somnath said :
“The velocity at the start of the landing process is almost 1.68 km per second, but this speed is horizontal to the surface of the moon. The Chandrayaan 3 here is tilted almost 90 degrees, it has to become vertical. So this whole process of turning from horizontal to vertical is a very interesting calculation mathematically. We have done a lot of simulations. It is here where we had the problem last time (Chandrayaan 2).”
Further, it has to be ensure that fuel consumption is less, the distance calculation is correct, and all the algorithms are working properly.
S Somnath said :
“Extensive simulations have gone, guidance design has been changed, and a lot of algorithms have been put in place to make sure that in all these phases required dispersions are handled….to attempt to make a proper landing,”.
Over five moves in the three weeks since the 14th July 2023 launch, ISRO had lift the Chandrayaan-3 spacecraft into orbits farther and farther away from the Earth.
Then, on 1st August 2023 in a key manoeuvre, a slingshot move, the spacecraft was sent successfully towards the Moon from Earth’s orbit.
Following this trans-lunar injection, the Chandrayaan-3 spacecraft escape from orbiting the Earth and began following a path that would take it to the vicinity of the moon.
Chandrayaan-3 is a follow-on mission to Chandrayaan-2 to demonstrate end-to-end capability in safe landing and roving on the lunar surface.
It comprises an indigenous propulsion module, a lander module, and a rover with the objective of developing and demonstrating new technologies required for inter-planetary missions.
The propulsion module will carry the lander and rover configuration till the 100 km lunar orbit.
The propulsion module has a Spectropolarimetry of Habitable Planet Earth (SHAPE) payload to study the spectral and polarimetric measurements of Earth from the lunar orbit.
The mission objectives of Chandrayaan-3 are to demonstrate a safe and soft landing on the lunar surface, to demonstrate rover roving on the Moon, and to conduct in-situ scientific experiments.
The lander will have the capability to soft land at a specified lunar site and deploy the rover that will carry out in-situ chemical analysis of the Moon’s surface during the course of its mobility.
The lander and the rover have scientific payloads to carry out experiments on the lunar surface.
