India launches third mission to the Moon

India has launched its third lunar voyage with a mission to the Moon’s south pole. The launch vehicle LVM-3 lifted off Chandrayaan 3 on a 384,000 km journey from the Satish Dhawan Space Centre in Sriharikota, on India’s southeast coast.

The rocket disappeared into a blanket of thick clouds to thunderous applause at the ground mission control room as Indian Space Research Organisation (ISRO) chairman S Somanath was seen congratulating scientists involved in the mission.

India’s Moon mission reflects the country’s strategy to be a part of an elite group of nations to maintain a long-term presence on the Moon. If all goes as planned, India will become only the fourth — after Russia, US and China — to soft-land a spacecraft on the Moon, and the only to land on the difficult south pole terrain.

The mission

Chandrayaan 3’s mission is to place a lander-rover in the highlands near the south pole demonstrating end-to-end landing and roving capabilities. The rover will carry out scientific measurements on the surface and while it’s in orbit.

After placing Chandrayaan 3 in a 170km x 36,500km elliptic parking orbit, the propulsion module will bring the lander-rover into a 100km circular polar lunar orbit and separate.

The lander will touchdown with its rover on Moon’s south polar region. ISRO sources said the touchdown is expected on August 23 or 24, 2023.

The lander-rover is like the Vikram rover on Chandrayaan 2, vastly improved to ensure a safe landing, unlike Vikram’s touch down, in which the lander lost contact with control.

“Soft landing in the polar region would be a critical enabler of future space ambitions,” said Tomas Hrozensky, senior researcher at the European Space Policy Institute.

Astrophysicists are hoping that the several payloads on board will add to understanding of lunar topography, seismography, mineral distribution, and surface chemical composition. The propulsion module has a Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload to enable spectral and polarimetric measurements of Earth from the lunar orbit.

Hrozensky said both technological innovations that bring down the cost of such missions and the non-technical elements have sparked renewed interest in the Moon.

The challenges

To reduce the risk of malfunction on the mission, ISRO has improved the rocket's software to have a higher tolerance for failures.

“During the second voyage to the Moon, we used five engines to reduce velocity —which is called retardation. These engines developed higher thrust than expected,” Somanath explained.

For Chandrayaan 3, engineers expanded the area of landing from 500m x 500m to 4km x 2.5 km. “So, if the performance is poor, it can land anywhere within that area," he said. Chandrayaan-3 also has more fuel for travel, handling dispersion, or to allow for an alternate landing site.

The Moon’s polar regions intrigue scientists for the abundant water ice found on the floors of permanently shadowed craters. Such ‘lunar cold traps’ contain a fossil record of the early solar system and harbour a precious resource that could aid human exploration of Earth's nearest neighbour.

But the polar regions are a very difficult terrain to explore. Lack of sunlight and extremely low temperatures make it difficult to operate instruments. The presence of large craters can also be challenging.

The spin-offs

“Soft landing of Chandrayaan 3 in a high-altitude region will consolidate India’s position in future international lunar missions including that of Artemis," Mylswamy Annadurai, the director of India’s first Moon mission, told Nature India.

“It is expected that along with raising ISRO’s stature, this mission’s success will help India’s commercial space sector attract global attention and bring more commercial contracts,” said Ajey Lele, space expert and consultant at the Manohar Parrikar Institute for Defence Studies and Analyses (MP-IDSA).