ISRO All Set to Initiate Automatic Landing Sequence for Chandrayaan-3 Lander

Bengaluru: The Indian Space Research Organisation (ISRO) is set to initiate the Automatic Landing Sequence (ALS) for its Chandrayaan-3 Lander Module (LM) on Wednesday, August 23, 2023. The LM, which comprises the Vikram lander and Pragyan rover, is scheduled to land at 6:04 pm IST, making it a historic achievement for India.

The ALS process begins when the LM receives the command, activating throttleable engines for a controlled descent. ISRO’s mission operations team will oversee the sequence of commands to ensure accuracy.

Chandrayaan-3 Mission:
All set to initiate the Automatic Landing Sequence (ALS).
Awaiting the arrival of Lander Module (LM) at the designated point, around 17:44 Hrs. IST.

Upon receiving the ALS command, the LM activates the throttleable engines for powered descent.
The… pic.twitter.com/x59DskcKUV

— ISRO (@isro) August 23, 2023

Upon confirming parameters, ISRO will upload necessary commands to the LM via the Indian Deep Space Network (IDSN) facility hours prior to the scheduled landing time. As the lander approaches about 30 km above the lunar surface, it enters the powered braking phase. It gradually reduces speed by employing four thruster engines in retro firing, preventing a crash due to lunar gravity.

Around 6.8 km altitude sees two engines remain active, providing reverse thrust for controlled descent. As the LM reaches 150-100 meters above the surface, its sensors and cameras assess obstacles before making a soft landing.

ISRO Chairman S Somanath highlights the challenge of reducing the lander’s velocity from 30 km altitude to the final landing, while also reorienting the spacecraft vertically.

The rover will disembark from the lander onto the Moon’s surface using a side panel as a ramp. Concerns about lunar dust are noted due to nearby engine firing during the landing.

Expected to function for a lunar day (about 14 Earth days), the lander and rover might extend their mission, offering additional insights into the lunar environment.