Chandrayaan 3 landing: How ISRO changed design after 2nd Moon mission's lander failure

Four years after the Chandrayaan 2 failed to land on the Moon, Indian space agency ISRO has learned from the errors.

The biggest difference is that for Chandrayaan 3, ISRO has gone for a 'failure-based' design rather than a 'success-based' design.

This means that ISRO assessed which parts can fail, and took steps to strengthen them.

These included putting more robust impact legs on the lander and installing additional sensors and cameras.

ISRO has also increased the landing area.

Chandrayaan 3 is also carrying more fuel, and the lander has more solar panels to generate power no matter how it lands.

This time, there is no orbiter module, and this simplifies the mission.

The Rs 600 crore Chandrayaan-3 mission was launched on July 14 onboard Launch Vehicle Mark-III (LVM-3) rocket, for a 41-day voyage to reach near the lunar south pole.

The soft-landing is being attempted days after Russia's Luna-25 spacecraft crashed into the Moon after spinning out of control.

After the second and final deboosting operation on August 20, the LM is placed in a 25 km x 134 km orbit around the Moon.

Also watch: Chandrayaan 3: Explaining why Chandrayaan 2 failed in landing on Moon in 2019

The module would undergo internal checks and await the sun-rise at the designated landing site, ISRO has said, adding that the powered descent -- to achieve soft-landing on the Moon's surface -- is expected to be initiated at around 5:45 pm on Wednesday.

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.

(with PTI inputs)