Chandrayaan-3: ISRO all set to initiate Automatic Landing Sequence

Vikram is the name of the lander, named after Dr Vikram A Sarabhai, the father of the Indian Space Programme. On the other hand, Pragyan the rover's name has been derived from the Sanskrit word meaning wisdom. The LM comprising the lander (Vikram) and the rover (Pragyan), is scheduled to make a touch down near the south polar region of the Moon at 6:04 pm on Wednesday. (Image: ISRO)

The Vikram lander comes with a multiple sensors to ensure a safe touchdown and also consists side-mounted solar panels, which can generate 738 W power that will be used to explore the lunar south pole. It has three payloads - RAMBHA-LP to measure the near surface plasma (ions and electrons) density and its changes with time; ChaSTE to carry out the measurements of thermal properties of lunar surface near polar region; ILSA to measure seismicity around the landing site and delineating the structure of the lunar crust and mantle. (Image: ISRO)

The six-wheeled rover named Pragyan is designed to provide data related to the lunar surface and elemental composition of the atmosphere. It weighs 26 kgs and has two payloads. The APXS payload will be used to derive the chemical composition and infer mineralogical composition to further enhance our understanding of lunar surface. On the other hand, the LIBS payload will determine the elemental composition (Mg, Al, Si, K, Ca,Ti, Fe) of lunar soil and rocks around the lunar landing site. (Image: ISRO)

The critical process of soft-landing has been dubbed by many including ISRO officials as "17 minutes of terror", with the entire process being autonomous when the lander has to fire its engines at the right times and altitudes, use the right amount of fuel, and scan of the lunar surface for any obstacles or hills or craters before finally touching down. After landing on the moon, the lnder and rover will be engaged to perform its own duties. Both the lander androver have a mission life of one lunar day, which is approximately 14 earth days. (Image: ISRO)

On July 15, ISRO successfully performed the first orbit-raising manoeuvre of the Chandrayaan-3 spacecraft on July 15, 2023. Subsequently, there were four more such orbit-raising manoeuvres on July 17, 18 and 25. Chandrayaan-3, completed its fifth and final Earth-bound orbit-raising manoeuvre on July 25, marking a crucial phase of the spacecraft's lunar trajectory. (Image: ISRO)

Chandrayaan-3 completed its orbits around the Earth and is now heading towards the Moon.A key manoeuvre to slingshot the spacecraft towards the Moon from Earth's orbit was carried out in the early hours of August 1. (Image: ISRO)

On August 5, Chandrayaan-3 was successfully inserted into the lunar orbit. "Chandrayaan-3 has been successfully inserted into the lunar orbit. A retro-burning at the Perilune was commanded from the Mission Operations Complex (MOX), ISTRAC (ISRO Telemetry, Tracking and Command Network), Bengaluru," ISRO said in a tweet. (Image: ISRO)

India's Moon Mission completed two successful orbit reduction maneuvers around the moon on August 6 and August 9. During the second orbit reduction, the retrofiring of engines brought the spacecraft closer to the Moon's surface, to 174 km x 1437 km. (Image: ISRO)

The orbit circulation phase commenced on August 14 as ISRO completed another successful maneuver of the spacecraft. "Orbit circularisation phase commences. Precise maneuver performed today has achieved a near-circular orbit of 150 km x 177 km," ISRO said in a tweet. Today’s successful firing, needed for a short duration, has put Chandrayaan-3 into an orbit of 153 km x 163 km, as intended. With this, the lunar bound manoeuvres are completed,” ISRO said on August 16. (Image: ISRO)

Lander Module of Chandrayaan-3 spacecraft comprising the lander and rover has successfully separated from the Propulsion Module, ISRO said on August 17. "Thanks for the ride, mate! said the Lander Module (LM). LM is successfully separated from the Propulsion Module (PM). LM is set to descend to a slightly lower orbit upon a deboosting planned for tomorrow around 1600 Hrs., IST," ISRO said in a post on X (formerly Twitter). (Image: ISRO)

Following this, the Vikram lander module underwent two succesful deboostings on August 18 and 20. “The second and final deboosting operation has successfully reduced the LM orbit to 25 km x 134 km. The module would undergo internal checks and await the sun-rise at the designated landing site. The powered descent is expected to commence on August 23, 2023, around 1745 Hrs. IST,” ISRO said on X. (Image: ISRO)

ISRO on August 21 said a two-way communication between the Chandrayaan-2 orbiter and Chandrayaan-3's Lunar Module has been established. "'Welcome, buddy!' Ch-2 orbiter formally welcomed Ch-3 LM. Two-way communication between the two is established. MOX has now more routes to reach the LM," it tweeted. (Image: ISRO)

Hours before landing, ISRO said it is all set to initiate the Automatic Landing Sequence (ALS) for Chandrayaan-3's Lander Module (LM) to touch down on the lunar surface. (Image: ISRO)