What is '17 minutes of terror' for Chandrayaan 3?

Indian Space Research Organisation's ambitious third Moon mission Chandrayaan-3's Lander Module (LM) is all set to land on the lunar surface on Wednesday evening, as India eyes to become the first country to reach the uncharted south pole of Earth's only natural satellite.

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.

According to ISRO officials, for landing, at around 30 km altitude, the lander enters the powered braking phase, and begins to use its four thruster engines by 'retro firing' them to reach the surface of the moon, by gradually reducing the speed.

This is to ensure the lander doesn't crash, as the Moon's gravity will also be in play.

Here is ISRO's SAC Director, Nilesh M Desai explains the crucial stage of soft landing.