Space Chief's Shocking Revelation: '15 Minutes of Terror' Returns with Chandrayaan 3 - Are We Ready for the Thrilling Ride?

Former ISRO head, K Sivan, famously likened the concluding stage of Chandrayaan 2's lunar landing to '15 minutes of terror', underscoring the immense complexities involved. This apprehension echoes the formidable task that lies ahead with Chandrayaan 3's lunar landing.

Among the multitude of hurdles facing the Chandrayaan 3 mission, a paramount one is the transition of the spacecraft from a horizontal orientation to a vertical one. Space strategist PK Ghosh conveyed the intricacy of this aspect, stating, "Achieving this feat presents a significant challenge," during an interview with the news agency ANI."

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Velocity stands as yet another pivotal factor that wields a decisive influence on the rover's landing process. The prospect of a “crash landing” loom when the lander's velocity remains uncontrolled. Citing an ISRO official quoted by the news agency ANI, the lander's manoeuvre involves descending from a 30 km altitude to the Moon's surface. During this phase, its velocity will be 1.68 km/sec. Progressing further, the descent continues to 7.5 km, where the velocity stabilizes at 3 m/sec. Subsequently, at an altitude of 800 m above the lunar surface, the velocity dwindles to nil.

"Afterwards, the deactivation of the two engines will ensue, allowing the lander module to touch down employing the remaining two engines, which will facilitate a retrograde thrust. Subsequently, it will embark on the phase of vertical descent," explained Nilesh M Desai, Director of the Space Applications Centre-ISRO, based in Ahmedabad, in an interview with ANI.

Algorithmic mishap: "Chandrayaan-2 encountered difficulties due to its Vikram lander's inability to regulate its velocity, leading to an uncontrolled descent... The root cause was an algorithmic anomaly, which has since been rectified. The legs of the Vikram Lander have been fortified to ensure greater resilience," remarked Professor Radhakant Padhi, an Aerospace Scientist, as quoted by NDTV."

 

Chandrayaan 3 landing: Impact

"LPDC imagery serves to aid the Lander Module in ascertaining its geographical coordinates (latitude and longitude) by cross-referencing them with an onboard lunar reference map. This concern looms as a prominent issue, resulting from the convergence of two factors: velocity and algorithmic performance. Should Chandrayaan 3 falter in nullifying its speed, the outcome might entail an impact landing on the lunar surface.

The Chandrayaan-3 Vikram lander, with a weight of 1,752 kg, accommodates a 26 kg rover named Pragyan. Notably, the lander of Chandrayaan-3 boasts a 'salvage mode,' designed to facilitate a landing even in the face of multiple contingencies. In a scenario where all sensors malfunction and conventional operations cease, the Vikram lander is engineered to execute a landing, contingent upon the propulsion system's functional state. Furthermore, measures have been implemented to ensure that the lander can still accomplish its mission if two of its engines experience non-operational status," recently stated ISRO Chairman S Somnath."

Chandrayaan 3 landing time and date: The scheduled time for Chandrayaan 3's touchdown on the lunar surface has been set at 6.04 pm by ISRO.