India’s Chandrayaan-3 and Russia’s Luna-25: race to Moon’s south pole heats up

PTI, Aug 17, 2023, 12:26 PM IST

The race to the uncharted south pole of the Moon is quickening with India’s Chandrayaan-3 and Russia’s Luna-25 gearing up for lunar landings next week, each mission holding significant implications beyond the thrilling competition in the skies.

While Chandrayaan-3 plans to be the first to land on the Moon’s south pole, Luna-25’s swift trajectory has cast new light, say experts as anticipation builds up. The proximity, possible overlap, of their landing dates — August 21-23 for Luna-25 and August 23-24 for Chandrayaan-3 — has intensified global scrutiny. Chandrayaan-3, the third mission in India’s lunar exploration series, began its journey on July 14 this year and successfully entered lunar orbit on August 5. It is meticulously adjusting its orbit in preparation for a soft landing attempt within 40 days of launch.

On Wednesday, its spacecraft successfully underwent a fifth and final lunar-bound orbit manoeuvre, taking it closer to the surface of the Moon. It has now completed all its Moon-bound manoeuvres and will now prepare for separation of the lander module — comprising the lander and rover — from the propulsion module.

Russia, which is making a momentous return to lunar exploration, its first in almost five decades since the iconic Soviet-era Luna-24 mission in 1976, launched Luna-25 on August 10. It is taking a more direct trajectory to the Moon, potentially allowing it to attempt a landing as early as August 21, about 11 days.

The rapid journey is attributed to the mission’s lightweight design and efficient fuel storage, enabling it to take a shorter path to its destination.

”Will the race make a difference? In the grand scope of cosmic exploration, the order of arrival may not significantly alter the lunar landscape. Yet, the knowledge gained from each mission will enrich our understanding of the Moon’s past and potential. The value lies in the sum of our combined efforts,” Chrisphin Karthick, scientist at Bangalore’s Indian Institute of Astrophysics, told PTI.

A key factor in the differing arrival times of the two missions is their respective mass and fuel efficiency. Luna-25 has a leaner lift-off mass of only 1,750 kilograms, significantly lighter than Chandrayaan-3’s 3,800 kg. This reduced mass allows Luna-25 to accelerate more effectively, according to India’s space agency ISRO.

Moreover, Luna-25’s surplus fuel storage eliminates fuel efficiency concerns, enabling it to undertake a more direct route, explained former ISRO chairperson Dr K Sivan. In contrast, Chandrayaan-3’s fuel-carrying capacity constraints required a more circuitous route to the Moon.

The spacecraft’s orbit was incrementally increased through a series of manoeuvres before being slingshot towards the Moon, culminating in its lunar orbit nearly 22 days after launch.

A crucial factor affecting the timing of these spacecraft landings is the path of the sun across the sky, the scientists said. The sun needs to be rising over the spots these probes are set to touch down on.

”I’m pleased to see Russia also embarking on a Moon mission. Global participation in space exploration amplifies the human spirit of curiosity and discovery,” Sivan told PTI.

”Both missions aim to touch down at the lunar south pole. While the order of arrival won’t significantly impact the mission outcomes, it does reinforce the collective commitment to exploring new frontiers,” he added.

The lunar landscape, he said, is unique and presents distinct challenges. The mission’s success isn’t solely determined by the order of landing.

“Lunar exploration demands higher thruster power and advanced technologies, each contributing to the overall success,” Sivan said.

”Payload considerations are pivotal in mission planning. The quest for the lunar south pole demands precision, efficiency, and adaptability. India’s mission showcases our dedication to achieving the highest thrust values, a testament to our technical prowess,” he said.

At a time of renewed global interest in space exploration, India and Russia stand at the precipice of historical achievements, both countries shaping the trajectory of humanity’s quest to uncover the secrets of Earth’s celestial neighbour.

As the world watches, both missions are expected to provide groundbreaking insights into the Moon’s composition, its history and potential as a resource-rich body.

Noting that healthy competition is a catalyst for growth, Karthick said the race to the lunar south pole fosters a dynamic environment where nations can learn from each other’s achievements and setbacks.

“This competition ignites a spirit of innovation, pushing us to improve our spacefaring capabilities collectively.” ”We are moving forward, adhering to our timeline. Our approach is grounded in sound physics that aligns with our economic reality. While cost-efficiency is a consideration, it doesn’t deter us from reaching for the stars. Our goal is to fulfill the aspirations of our nation while adhering to responsible resource management,” Karthick added.

The lunar south pole holds particular interest due to its potential water resources and unique geological features. The relatively unexplored region is pivotal for future lunar missions, including the upcoming Artemis-III mission by US space agency NASA, which aims to carry humans to the Moon after a five-decade hiatus.

”The uncharted terrain of the lunar south pole beckons us with the promise of unravelling more profound insights about our celestial neighbour. Our mission to the Moon is a testament to our resolve to explore the unknown.” Karthick said.

”The south pole of the Moon offers a treasure trove of scientific opportunities. Investigating this region will yield valuable insights, contributing to our understanding of the Moon’s history and evolution,” he added.

Experts say the findings from these missions will not only enrich our understanding of the lunar environment but also pave the way for future lunar exploration endeavours.

”Through these missions, we will gain new technological capabilities that will expand our expertise in space exploration. Each mission holds the potential for groundbreaking science experiments that will broaden our understanding of the Moon’s mysteries.” Sivan said.