‘Smooth sailing’ as Chandrayaan-3 touches down today

As Chandrayaan-3's Lander Module got ready to make a "safe and soft landing" on the Moon's surface Wednesday evening, a surge of expectation rocked the nation.

If everything goes according to plan, India will become the first nation to land a spacecraft on the lunar south pole during the Moon landing, which will be the best achievement of its space program to far and put an end to the disappointment caused by the Chandrayaan-2 lander's four-year crash-landing.

In a social media post on Tuesday, the ISRO said that the Mission Operations Complex (MOX) has been humming with "energy" and "excitement".

"The task is finishing on time. System inspections happen on a regular basis. The sailing is still calm, according to ISRO.

The Chandrayaan-3 lander will touch down on the moon on Wednesday at 1804 IST after a 17-minute drop from its current pre-landing orbit.

At 1747 hours, a directive from ISRO's Telemetry Tracking and directive Centre (ISTRAC) in Bengaluru will trigger the spacecraft to start the fall.

The spacecraft will have to decelerate down to almost zero speed when it makes a touchdown from an orbital velocity of around 6,000 km/h. It is made to land safely even at 10 km/hr speeds.

The spacecraft will begin to fall at 1747 hours after receiving a command from ISRO's Telemetry Tracking and directive Centre (ISTRAC) in Bengaluru.

When the spacecraft lands, it will have to slow down from an orbital velocity of roughly 6,000 km/h to nearly nothing. Even at 10 km/h speeds, it is designed to land safely.

According to ISRO, Chandrayaan-3 made contact with the Chandrayaan-2 orbiter on Monday. Mission control in Bengaluru will receive data on signals sent by the Chandrayaan-3 lander directly to ground stations at the Deep Space Network in Bengaluru, the Jet Propulsion Laboratory in the US, and a European Space Agency station in Spain or via that orbiter.

However, as soon as the descent phase starts, mission control can no longer issue directives to the lander. The lander will need to employ its preprogrammed AI to perform a "safe and soft landing" once the fall has begun.

The Chandrayaan-3 lander, according to ISRO Chairman S. Somanath, is developed using a failure-based strategy, which means that multiple layers of safety measures have been added to accommodate for every possible type of failure scenario.

The spacecraft's legs have been reinforced so that it can land safely even at higher speeds, and its software has been updated. Its fuel capacity has also risen, as has its capacity for maneuvering and locating a suitable landing site.