What is the '15 minutes of terror' in Chandrayaan-3's high-stakes lunar landing?
Chandrayaan-3 lander will face a pivotal moment in its mission to achieve a soft lunar landing. During the final 15 minutes of its descent onto the Moon's surface, the lander must transition from a high-speed horizontal position to a vertical one.
The success of this maneuver will determine the mission's outcome, echoing the sentiments of ISRO's former chairman, K Sivan, who once referred to this phase as «15 minutes of terror.»
This last leg of the mission carries a heavy burden, with vivid memories of Chandrayaan-2's 2019 failure when the Vikram lander failed to execute the necessary transition, leading to a lunar surface collision during the «fine braking phase,» just 7.42 km from the target.
Recently, the Chandrayaan-3 lander underwent a crucial deboosting process to adjust its orbit to 25X134 km around the Moon, preparing for the upcoming landing attempt.
The landing process involves a simultaneous reduction of the lander's horizontal velocity from a staggering 1.68 km/sec (over 6,000 km/h) at 30 km above the lunar surface to nearly zero, ensuring a gentle touch down at the designated site, approximately 70 degrees South latitude. The anticipated landing is scheduled for 6:04 pm India time on August 23.
As ISRO Chairman S Somanath explained, the challenge lies in turning the lander from its nearly 90-degree tilt during the start of the landing process at 5:47 pm on August 23 to a vertical position, a critical maneuver that led to Chandrayaan-2's mishap in 2019.
