India's Chandrayaan-3 is all set to make history. Along with 140 crore Indians, the eyes of the whole world are fixed on this mission. It is expected to land at 6:04 pm. After checking all the parameters and deciding on the landing, ISRO will upload all the necessary commands to the landing module a few hours before the landing from its Indian Deep Space Network (IDSN) at Bailalu near Bengaluru. The soft-landing process will be completed in 19 minutes. 17 of those minutes will be very important. Meanwhile, the engine of the Lander has to be started at the right time and at the right altitude. Proper amount of fuel has to be used and before landing it has to be ensured that there is no obstacle, hill or pothole.

These four stages will be important

1. Rough breaking phase: At present, the velocity of Chandrayaan-3 in a 25 km x 134 km orbit around the Moon is about 1680 meters per second. The lander will begin its descent to the lunar surface from an altitude of 25 km. The velocity will decrease by firing the four engines fitted to the Vikram lander.

2. Altitude Hold Phase: "Altitude Hold Phase" will be performed for about 10 seconds. During this time the lander will tilt from horizontal to vertical position covering a distance of 3.48 km. Altitude will be reduced from 7.42 km to 6.8 km and velocity will be reduced to 336 m/s (horizontal) and 59 m/s (vertical).

3. Fine breaking phase: This process will last for 175 seconds. In this phase the lander will go completely vertical, the altitude will drop from 6.8 km to 800/1000 m and the speed will be almost zero m/s. On reaching an altitude of about 6.8 km, only two engines will be used. The other two engines will be shut down. On reaching an altitude of 150 to 100 meters, the lander will use its sensors and cameras to scan the surface and check if there are any obstacles and then begin its descent to perform a soft-landing.

4. Terminal Descent Phase: When the lander is about 10 meters above the designated landing site, all its engines will shut down so that it can descend directly on its feet. This will be the last step. Throughout the process, special sensors mounted on the Vikram lander and an onboard computer will continuously monitor its orientation.