Scientists are celebrating as India lands on the moon

Chandrayaan 3, India’s third lunar mission, launched 14 July 2008, is excited by its mission and aims to improve the exploration of the lunar surface

An Indian space probe has become the first to land near the Moon’s rock- and crater-strewn south pole, making the country the world’s fourth to successfully perform a controlled landing on the body.

Chandrayaan 3, India’s third lunar mission, lifted off on 14 July. A 1.7-ton landing module on a six-wheeled robotic rover called “Pragyan” is being carried by a 3.9-ton spaceship that was launched. Pragyan will ramble around the landing site for one lunar day, equivalent to 14 Earth days.

Experiments in the moon can be seen as a proving ground for engineering and science. Previous ISRO missions have already brought about fresh lunar science. India’s first Moon mission, the Chandrayaan-1 orbiter, launched in 2008 and helped to confirm the existence of water on the Moon with data gathered by a NASA instrument on board (C. M. Pieters et al. Science, 368–528. Even though the lander crashed, the orbiter continued to map and study the lunar surface. If Chandrayaan-3 continues to function well, it will collect data on the chemistry and mineralogy of the surface.

The landing “gives confidence to configure missions to go to the Moon, Mars, Venus, maybe even asteroids”, ISRO chairman S. Somanath told a press briefing.

These include a new laser sensor to measure the real-time velocity of the spacecraft relative to the Moon, algorithms to handle unanticipated deviations in propulsion or trajectory and better judge the landing terrain, bigger and more solar panels, more fuel, a heavier lander equipped with four sturdier legs to handle a faster landing velocity.

In particular, it requires putting the spacecraft into a polar orbit that is at right angles to the Moon’s orbit, says Norman. “This requires additional energy to move the spacecraft into an ‘unnatural’ orbit, which introduces uncertainties on critical aspects such as velocity and location of the spacecraft.”

The region does not have sufficiently detailed information on its gravity and surface characteristics. “For example, if the spacecraft lands in a crater, on a slope, or the leg of the lander catches on a boulder, the mission could be compromised.”

Moon quakes near the area add complexity, says geologist Saumitra Mukherjee at the Jawaharlal Nehru University in New Delhi, whose team analysed images sent by India’s first lunar mission, Chadrayaan-1, which launched in 2008 and detected cliffs and signs of displaced underground rocks in two craters near the lunar south pole.

There is a problem with the lighting from the Sun. The sun angles in the dark are so far from the terrain that it blocks out any features. The Apollo landing sites were specifically chosen to make sure quality lighting of the lunar terrain, such as rocks and craters.

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Chandrayaan-3’s success comes about a week before ISRO’s next major mission — its first to study the Sun — which is scheduled to launch in the first week of September.

Earlier today, the mission’s landing module Vikram, named after physicist Vikram Sarabhai, considered the founder of India’s space programme, deployed a small rover that will study lunar rocks and dirt. The solar-powered mission is meant to last for two weeks, until lunar night hits this part of the surface.

The head of the Russian space agency said this week that the country’s lunar programme had been paused for more than four decades, causing the Moonshot failure. ISRO, by contrast, has steadily built on its achievements, including ramping up its engineering talent, although it has declined to reveal how much — or how little — it spent on Chandrayaan-3.

Indian Prime Minister Narendra Modi, who joined millions of people in watching the final descent, rightly said: “This success belongs to all of humanity.” It is a great achievement for India’s scientists and engineers.