India’s remarkable Chandrayaan-3 mission has etched its name in the records of space history as it achieved an unprecedented feat – a successful soft landing on the Moon’s south pole on the 23rd of August 2023. This milestone makes India not only the fourth country to land a spacecraft on the lunar surface, after Russia, the US, and China, but also the first to achieve this remarkable feat in the challenging lunar south pole region.
The historic moment unfolded at 8:33 am ET (6:03 p.m. India Standard Time) as India’s Chandrayaan-3 gracefully touched the lunar surface. The Indian Space Research Organization (ISRO) confirmed the successful landing, marking a monumental accomplishment in the nation’s space endeavors. With resounding pride, ISRO chairman Sreedhara Somanath proclaimed, “We have achieved soft landing on the moon! India is on the moon!”
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India on the Moon!
The Triumph of Soft Landing
Chandrayaan-3’s achievement lay in its ability to conduct a ‘soft landing,’ a meticulous process that involved landing a spacecraft gently and controlled on the lunar surface to prevent any damage. Dr. Amitabha Ghosh, a scientist associated with NASA’s Rover mission to Mars, eloquently explained soft landing in the Indian Express: “Imagine a spacecraft hurtling through space, at 10 times the speed of an airplane, having to nearly come to a standstill in order to land gently on the Earth — all in a matter of a few minutes and, more importantly, without any human intervention. This, in a nutshell, is a soft landing.”
The lander’s successful descent was a culmination of several critical phases, including the rough braking phase to reduce horizontal velocity, the delicate transition from a horizontal to a vertical position, a fine braking phase to further slow down and reach the landing site, and the terminal descent for a vertical landing onto the lunar surface.
The Significance of the Lunar South Pole
Chandrayaan-3’s chosen landing site at the lunar south pole is not a random decision. This region holds immense scientific potential due to its mysterious water ice deposits and the unexplored terrain. While previous missions predominantly focused on the Moon’s equatorial regions for ease and safety, the lunar south pole offer unique insights into the moon’s geological history and potential resources. Moreover, the extremely cold temperatures preserve the terrain, making it a potential treasure trove of information about the early Solar System.
Unveiling Lunar Mysteries
As Chandrayaan-3 embarked on its scientific mission, it carried a suite of advanced instruments designed to unveil lunar mysteries. The Vikram lander and Pragyan rover bore six payloads, including scientific instruments that studied lunar quakes, the thermal properties of the lunar surface, changes in plasma near the surface, and the precise measurement of Earth-Moon distance. The Rover itself housed two payloads aimed at analyzing the chemical and mineral composition of the lunar surface, shedding light on elements such as magnesium, aluminum, and iron present in the lunar soil and rocks.
The collaborative spirit of this mission was highlighted by NASA’s contribution of a scientific payload, underscoring the global significance of Chandrayaan-3’s efforts.
The Critical Phases of India’s Chandrayaan-3’s Successful Lunar Landing
The intricate dance of science and technology that led to Chandrayaan-3’s triumphant landing involved a series of precisely orchestrated maneuvers, each holding the key to a soft touchdown on the Moon’s surface. The critical technical maneuver on August 23rd marked the climax of a carefully planned sequence that played out over the final 15 minutes of the mission, transitioning the lander from a high-speed horizontal position to a gentle vertical descent.
Drawing from the lessons of Chandrayaan-2’s unfortunate landing, K Sivan, the then chairman of ISRO, famously referred to this sequence as the “15 minutes of terror.” This phase encompassed four pivotal stages, each executed with extraordinary precision and expertise.
- The Rough Braking Phase: This phase involved the reduction of the lander’s horizontal velocity, which was initially a swift 1.68km/sec (equivalent to over 6,000 km/h) at a height of 30km above the lunar surface. The objective was to bring the velocity to nearly zero, a critical step for ensuring a gentle landing at the designated site. This intricate task demanded meticulous timing and control to execute flawlessly.
- Attitude Hold Phase: As the lander descended to an altitude of 7.42 km, it transitioned into the “attitude hold phase.” This brief interval, lasting around 10 seconds, saw the lander tilting from a horizontal to a vertical position while covering a distance of 3.48 km. This transition was vital in preparing the lander for its final approach, ensuring it was optimally positioned for the subsequent phases.
- Fine Braking Phase: Lasting approximately 175 seconds, the “fine breaking phase” was a delicate operation that required the lander to move fully into a vertical position. Covering a distance of 28.52 km, this phase was crucial in further reducing the lander’s velocity and altitude. By the time it reached an altitude of 800-1,000 m, the lander’s speed was nominal, nearing 0 m/sec. It’s noteworthy that Chandrayaan-2 encountered difficulties during the transition from the “attitude hold phase” to the “fine breaking phase,” leading to its unfortunate end.
- Terminal Descent: The ultimate phase, the “terminal descent,” marked the culmination of Chandrayaan-3’s journey as the spacecraft descended vertically onto the lunar surface. This phase demanded the utmost precision, as any deviations could have jeopardized the mission’s success.
A Glimpse into the Future
Chandrayaan-3’s successful landing marks the beginning of an exciting chapter in lunar exploration. Its success not only amplifies India’s space capabilities but also kindles the spirit of scientific inquiry worldwide. As the mission unfolds and data streams back to Earth, scientists and researchers anticipate revelations about the moon’s evolution, geological history and potential as a resource-rich celestial neighbor.
In the grand tapestry of space exploration, Chandrayaan-3 has woven a thread of innovation, determination and discovery. It propels us toward a future where the moon’s mysteries are illuminated, and humanity’s quest for knowledge reaches ever-greater heights.