July 14: LVM3 M4 vehicle successfully launches Chandrayaan-3 into orbit from Sriharikota in Andhra Pradesh. Chandrayaan-3 starts its journey into precise orbit.

July 15: First orbit-raising manoeuvre (Earthbound firing-1) successfully performed from ISTRAC/ISRO, Bengaluru. The spacecraft is in 41762 km x 173 km orbit.

July 17: Second orbit-raising manoeuvre performed. Spacecraft is in 41603 km x 226 km orbit.

July 22: Another orbit-raising manoeuvre completed using earth-bound perigee firing.

July 25: ISRO performs one more orbit-raising manoeuvre. Spacecraft is in 71351 km x 233 km orbit.

August 1: ISRO performs Translunar Injection successfully and inserts the spacecraft into translunar orbit. Orbit achieved is 288 km x 369328 km.

August 5: Lunar-Orbit Insertion of Chandrayaan-3 performed successfully. Orbit achieved is 164 km x 18074 km, as intended.

August 6: ISRO performs second Lunar Bound Phase (LBN). With this, the spacecraft is in a 170 km x 4313 km orbit around the Moon. The space agency releases video of the Moon as viewed by Chandrayaan-3 during lunar orbit insertion.

August 9: Chandrayaan-3’s orbit is reduced to 174 km x 1437 km after a manoeuvre is performed.

August 14: Mission is in orbit circularisation phase after another manoeuvre. The spacecraft is in 151 km x 179 km orbit.

August 16: Spacecraft brought down to an orbit of 153 km x 163 km after firing is completed.

August 17: Lander module is successfully separated from the propulsion module.

August 19: ISRO performs de-boosting of the lander module to reduce its orbit. The lander module is in 113 km x 157 km orbit around the Moon.

August 20: One more de-boosting or orbit reduction manoeuvre on the lander module is performed. The lander module is in 25 km x 134 km orbit.

August 21: Chandrayaan-2 orbiter formally welcomes Chandrayaan-3 lander module saying ‘Welcome, buddy!’. Two-way communication between the two is established. Mission Operations Complex (MOX) now has more ways to communicate with the lander module.

August 22: ISRO releases images of the Moon captured by the Lander Position Detection Camera (LPDC) of the Chandrayaan-3 mission from an altitude of about 70 km. Systems are undergoing regular checks. Smooth sailing is continuing.

August 23: Safe and soft landing of Chandrayaan-3’s lander module on the southern pole of lunar surface expected at 6.04 p.m. – PTI

Students with painted faces surround a replica of the Chandrayaan-3 spacecraft in Chennai on August 22, 2023.
| Photo Credit: AFP

Four years after its predecessor crashed on the lunar surface minutes before touch down, Chandrayaan-3’s lander module with the rover in its belly on Wednesday will once again attempt to land on the Moon at 6.04 p.m.

Around 5.45 p.m., the Mission Operations Complex (MOX) at ISRO Telemetry, Tracking, and Command Network (ISTRAC), Bengaluru, will initiate the powered descent of the lander module.

Also Read — What next for ISRO after Chandrayaan-3 mission?

If all goes as per plan, 19 minutes later at 6.04 p.m., the lander would make a safe and soft landing on the Moon and would make India the fourth country to achieve this feat after the U.S., Russia and China.

The complex powered descent during the Chandrayaan-2’s was referred to as “15 minutes of terror” by the then ISRO Chairman K. Sivan. It can be recalled that Chandrayaan-2’s Vikram lander almost evaded this “15 minutes of terror” but it gave up at an altitude of 2.1 km before touchdown and subsequently lost communication with the ground stations.

More robust

However, with the Chandrayaan-3 mission, ISRO has made several changes to make the mission a success, which include strengthening of the landers’ legs, reduction in the number of engines, increasing the quantity of propellant, inclusion of new sensors among others.

Earlier this month, ISRO Chairman S. Somanath said that even if all sensors fail while attempting to make the soft landing on the lunar surface, the lander would still be able to land provided that the propulsion system works.

“If all the sensors fail, we will still be able to land provided that the propulsion system works. Even if the two engines fail, we will be able to land, that’s how the design has been made,” Mr. Somanath said.

He added that this time they have made all the systems more robust and have changed the guidance design and introduced newer algorithms.

Rover deployment

A few hours after ISRO succeeds in making a safe and soft landing of the lander on the lunar surface, it will deploy the rover which will carry out in-situ chemical analysis of the lunar surface during the course of its mobility. The lander and the rover with a mission life of one Lunar day (14 earth days) have scientific payloads to carry out experiments on the lunar surface.

The Chandrayaan-3 mission was launched on July 14 from the Satish Dhawan Space Centre in Sriharikota. Since then Earth-bound manoeuvres, crucial trans-lunar injection (TLI), lunar orbit insertion, orbit reduction manoeuvres were carried out along with the separation of the propulsion module and the lander module.

ISRO on Tuesday said the mission was on schedule with systems checks being carried out by scientists and engineers. “The mission is on schedule. Systems are undergoing regular checks. Smooth sailing is continuing. The Mission Operations Complex [MOX] is buzzed with energy & excitement!,” ISRO posted on social media platform X on Tuesday.