India’s Chandrayaan-3 and Russia’s Luna-25 Missions Vastly Different: ISRO Scientist

NEW DELHI: India’s third lunar mission, Chandrayaan-3, is very different when compared to that of Russia’s Luna-25 in terms of methodology, route and experiments, said Indian rocket scientists on Saturday.

Chandrayaan-3 was launched by ISRO on July 14, while Russia was successful in launching its first moon-landing spacecraft on Friday (Aug 11). Luna-25 will be completing the journey to the moon in 10 days, as compared to 40 days for Chandrayaan-3, because it is riding on a high-powered rocket, while the Indian craft largely makes use of the gravitational forces of the earth and the moon.

Both India’s and Russia’s lunar missions will attempt to land on the lunar south pole, the first time any craft from earth will land in that zone.

While Chandrayaan-3, which was launched from the Satish Dhawan Space Centre in Sriharikota on July 14, is scheduled to land on the lunar surface on August 23 after completing a 40-day journey, Russia’s Luna-25, which took off on August 11, is expected to land on the moon’s surface on August 21, two days ahead of Chandrayaan-3. Originally, Luna-25 was slated to land on the moon on the same day, i.e. August 23, the date was later changed by Russian space agency Roscosmos to August 21, in the effort to be the first to land near the moon’s south pole.

The difference in the time to reach the moon is because India’s spacecraft relies heavily on the gravitational forces of the earth and moon, explained a scientist at the Indian Space Research Organisation (ISRO), unlike the Russian Luna-25, which is using a high-powered rocket Soyuz 2.1, which includes a higher fuel load that is capable of powering the spacecraft throughout the mission, without having to resort to any external forces.

After Chandrayaan-3 was launched by ISRO, it was then placed into an elliptical orbit around the earth, after which the craft kept revolving or orbiting the planet until the space agency carried out some manoeuvres to raise its orbit. It was then gradually pushed away from the planet and finally guided into a lunar orbit, the unnamed scientist explained.

A similar pattern of manoeuvres is being used by ISRO after Chandrayaan-3 entered the moon’s orbit. It is continuing to perform orbit-reducing moves till the spacecraft reaches an orbit that is closer to the moon’s surface and then proceed to make a soft landing.

“India’s space programme is based on the principle of frugal innovations. We try to make our missions as cost-effective as possible,” the ISRO official said. “Our mission might be taking longer, but we are ensuring that our journey to the moon is extremely fuel-efficient and cost-effective.”

India used the same methodology in two of the previous moon missions, Chandrayaan-1 in 2008 and Chandrayaan-2 in 2019.

In order to send Luna-25 to the moon, Russia is using a powerful rocket named Soyuz 2.1, which can provide the necessary thrust to the spacecraft to reach the moon’s surface directly, without having to wait in earth’s orbit before moving towards the moon.

India’s space agency launched its lunar craft on-board the Launch Vehicle Mark-3, earlier known as the GSLV MK3, which has far lesser quantity of fuel and thrust. Similarly, it also has limitations of the payload capacity which can be sent to the moon.

Chandrayaan-3 is a follow-up mission to the failed Chandrayaan-2 and aims to demonstrate its end-to-end capability, for a safe landing and roving on the lunar surface.

The spacecraft includes a lander and a rover, which will be carried by a propulsion module till it reaches a 100km lunar orbit.

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