Chandrayaan-3: Vikram And Pragyan Are Halfway Through Their Mission Life. Know What Happens At The Mission's End

Chandrayaan-3's Vikram lander and Pragyan rover have a mission duration of 14 days, and are halfway through their mission life. Will they return to Earth after their mission is over?

Chandrayaan-3's Vikram lander (left) and Pragyan rover (right) began operations on the Moon the day after the lander module's landing. In just a week, the payloads onboard Vikram and Pragyan have made groundbreaking scientific discoveries. ( Image Source :ISRO )

Chandrayaan-3, which softly landed on the lunar south pole on August 23, 2023, has been operating on the Moon for over a week. With the successful landing of Chandrayaan-3’s Vikram lander on the Moon’s south pole, India became the first country in the world to softly land a spacecraft on the lunar south pole. About four hours after the historic touchdown, the Pragyan rover rolled out of the Vikram lander. The lander and the rover began operations the day after the landing. In just a week, the payloads onboard Vikram and Pragyan have made groundbreaking scientific discoveries.

Both the spacecraft have a mission duration of 14 days, and are halfway through their mission life. They are transmitting data back to Earth through the Indian Space Research Organisation’s (ISRO) Deep Space Antenna Networks.

What happens to Vikram and Pragyan at the end of their mission? Will they return to Earth? 

Well, the answer is that both Vikram and Pragyan will be left on the lunar surface after their mission life is over, and will be decommissioned. The reason why they have a short mission life is that they generate power using solar energy.

“After the mission life is over, the lander and the rover will be left on the lunar surface and will be decommissioned. Since the lander and the rover rely on solar panels to generate power, the mission is restricted to only 14 days,” Debadatta Mishra, a former ISRO scientist, and co-founder of Erisha Space, a New Delhi-based space-tech firm, told ABP Live. 

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However, several spacecraft often outlive the duration they were originally designed to operate for. This means that Vikram and Pragyan can also be expected to function beyond their mission life of 14 days.

“Chandrayaan -3 is not designed to return to the earth. Vikram and Pragyan will remain on the lunar surface. If the lander and the rover remain functional (often they do), ISRO will continue collecting data about the lunar surface using them,” said Dr Sanat K Biswas, Assistant Professor, Space Systems Laboratory, Indraprastha Institute of Information Technology, Delhi (IIIT-Delhi).

Since Vikram and Pragyan will remain on the Moon, will they be considered space junk?

Another point to ponder is whether Vikram and Pragyan can be considered as space junk or space debris after they become defunct. Since Vikram and Pragyan will remain on the Moon’s surface after becoming defunct, they cannot be considered space junk, which refers to the non-functional objects remaining in Earth’s orbit. 

“Space debris, often referred to as space junk, encompasses defunct human-made objects that linger in Earth's orbit, posing a risk to active spacecraft. These objects include abandoned spacecraft, fragments from disintegration, and even minuscule particles resulting from various space activities. However, it's important to clarify that objects left on the lunar surface, like Vikram and Pragyan, do not contribute to the space junk dilemma,” said Manish Purohit, a former ISRO scientist who was involved in the Chandrayaan-2 and Mangalyaan mission.

Since Vikram and Pragyan are not floating in Earth’s orbital space, and are lunar artefacts, they cannot be considered space junk.

What makes Chandrayaan-3’s soft landing historic? 

The lunar touchdown was itself a testament to the calibre of ISRO because the lander was at a high velocity while orbiting the Moon, but managed to maintain a controlled speed during lunar descent, with the help of a propulsion system. 

“Chandrayaan-3’s Vikram lander had a very low vertical speed at the time of touchdown to ensure that the lander was not damaged,” said Mishra.

The vertical speed of the lander module was reduced with the help of the engines in the spacecraft. The lander module’s four 800 Newton engines were continuously fired during the powered descent phase, which began about 25 minutes before lunar touchdown. 

“This long manoeuvring phase required detailed calculations and analysis, which were done onboard with data collected from all sensors. The lander module’s vertical speed before touchdown was reduced to about two to three metres per second,” said Mishra.

He explained that the landing was just like a “soft feature touch”.

Comparing how an aeroplane uses the forces exerted by its wings, landing gear, and brakes to land, Mishra said that the Vikram lander used the force generated by the opposite firing of the propulsion system to land on the Moon. This is called braking the forward movement.

Pragyan’s payloads have confirmed the presence of sulphur on the Moon’s south pole, and Vikram’s instruments have produced the first temperature-depth profile of the lunar surface on the south pole. Both Vikram and Pragyan are expected to operate on the Moon till September 7 or 8.