Chandrayaan-3 and Luna-25 take-off
Image: Chandrayaan 3: Courtesy ISRO and Luna-25: Handout / Russian Space Agency Roscosmos / AFP
The third week of August could mark a big leap for space exploration. Two lunar missions, India’s Chandrayaan-3 and Russia’s Luna-25, are in a race to successfully land on the uncharted south polar region of the Moon to become the first ever country to do so. The lunar south pole holds the key to future space missions. Besides, as discovered by Chandrayaan-1, there is a high possibility of potential water resources and an opportunity to understand the unique geology of a possibly mineral-rich terrain.
Russia’s mission to the Moon—after nearly five decades—came as a surprise. The Russian Space Agency’s Luna-25 was launched after a delay of two years on August 10. It is expected to touch down on the lunar south pole, near the Boguslavsky crater, between August 21 and 23. India’s third lunar mission, Chandrayaan-3, was launched nearly a month earlier on July 14 and is scheduled to land on the lunar south pole on August 23 or August 24.
In an interaction with news agency PTI, Chrisphin Karthick, a scientist at Bangalore’s Indian Institute of Astrophysics, rhetorically asked, “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.”
That is the true human spirit of curiosity and exploration of new frontiers. Other concerns of collision were assuaged by the Russian Space Agency: “Luna-25 and Chandrayaan-3 have been designated different landing sites. The risk of interference or collision is non-existent. Sufficient space exists on the Moon for all activities. Luna-25 will remain stationary and won’t traverse the lunar surface,” Ilya Morozov, spokesperson, Center of Internal and External Communications, State Corporation Roscosmos, reportedly stated.
Although Luna-25 was launched 28 days after Chandrayaan-3, its lighter mass and fuel efficiency will allow it to complete the journey to the Moon in around 12 days (see table). For example, Luna-25 weighs 1750 kg in comparison to Chadrayaan-3’s weight of 3,900 kg. This allows the Russian spacecraft to accelerate and gain speed. Moreover, Luna-25 has surplus fuel storage. So, unlike Chandrayaan-3 which had to take a circuitous route to the Moon to conserve fuel, Luna-25 can take a direct route to enter the lunar orbit faster. Luna-25’s lander is expected to operate experiments on the Moon’s surface for one year.
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As per a detailed note by NASA, the lander has a four-legged base containing the landing rockets and propellent tanks. An upper compartment holds most of the science apparatus such as the solar panels, communication equipment, on-board computers, radio-thermal heaters and radiators. “The lander has a 1.6-meter-long Lunar Robotic Arm (LRA) to remove and collect the surface regolith to depths of 20 to 30 cm,” the space agency said in the note. There are eight science instruments. First moon images sent back by Chandrayaan-3 Image: Courtesy ISRO
Roscosmos said its mission’s lunar landing process will happen in multiple phases. It explained the journey from Earth to the Moon will be completed in five days and the lunar orbit will be maintained for five to seven days depending on landing conditions around its chosen location.
India’s third lunar exploration mission, Chandrayaan-3, aims to achieve what Chandrayaan-2 partially failed to do four years ago. A successful soft landing on the Moon will make India the fourth country, after the US, Russia, and China, to achieve this difficult first step of interplanetary exploration. In its second attempt at soft-landing on the Moon, ISRO aims to collect more information about the lunar landscape, seismic measurements, and the availability of minerals, for example.
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On July 14, after LVM3 M4 majestically lifted off from Sriharikota, in around 16 minutes, it successfully launched Chandrayaan-3 into orbit at an altitude of around 180 km. Then, it orbited the Earth in an elliptical cycle 5-6 times as it moved towards the lunar orbit with some acceleration and a series of engine firings to hurl the spacecraft closer to the lunar orbit. In the lunar orbit, on August 17, the Lander Module successfully separated from the Propulsion Module, in the final leg of its journey. Moon: This handout photograph taken by the Luna-25 rover (Moon-25) and released by Russian Space Agency Roscosmos on August 17, 2023, shows the Zeeman lunar impact crater on the far side of the Moon. Image: Handout / Russian Space Agency Roscosmos / AFP
Now, the Propulsion Module will continue its journey in the current lunar orbit for months and years to send perform spectroscopic study of the Earth’s atmosphere and measure the variations in polarisation from the clouds on Earth to gather signatures of exoplanets, ISRO said. The Lander will move towards the Moon and aim for a soft landing on August 23. On the lunar surface, it will conduct planned experiments for 14 days.
India’s previous mission, Chandrayaan-2, in September 2019, failed in the last leg of its attempt as the lander and rover crashed on the Moon surface. ISRO’s chairman elaborated that the reason for the previous unsuccessful attempt was largely that the five engines on the lander developed a higher-than-expected thrust. Due to software-related issues, the lander couldn’t course-correct when it deviated from its trajectory and was unable to slow down the velocity in order to land as planned.
This could very well be a historic moment for India as the nation tries to make strides in space exploration. The world is closely watching the developments as the race between Russia and India to land on the lunar south pole intensifies. In the coming years, the US and China hope to send astronauts to the Moon, and around six robotic missions from Russia, Japan, and the US are lined up for this year and 2024. ISRO indicated, as of July, there are six active lunar orbiters in space, and China’s Yutu-2 rover of the Chang’e 4 mission is the only operational rover stationed on the far side of the Moon.