India Sets Its Sights on the Moon’s South Pole: Chandrayaan-4 Sample Return Mission Slated for 2028

The successful landing of Chandrayaan-3 on the Moon in 2023 has fanned India’s space ambitions. On 18the September 2024, India’s cabinet approved two important space science missions: the Venus Orbiter Mission (VOM) to study various aspects of Venus, including its surface and atmosphere, and the Chandrayaan-4 mission to develop and demonstrate technologies for returning to Earth after a successful lunar landing and collecting lunar samples to analyse them on Earth.

These missions will be essential steps towards the Space Vision 2047 programme, which envisages India becoming one of the most influential space powers, with the Bharatiya Antariksha station in orbit by 2035 and a homegrown technology to land on the Moon by 2040.

This will require the achievement of several technologies, such as heavy launch vehicles, manned spacecraft, docking technologies, heavy lift landing vehicles, and re-entry technologies.

Technology and science will drive the roadmap for the country’s space programme, which is being systematically discussed with scientists from national institutes and academia.

India’s fourth mission to the Moon

India sent three space missions to the Moon under the Chandrayaan series in 2008, 2019 and 2023, respectively.

The first two missions, Chandrayaan-1 and Chandrayaan-2, studied the lunar surface, subsurface, and exosphere globally from orbiting platforms. The Chandrayaan-3 mission made the first-ever successful soft landing on the Moon and conducted a robotic exploration of its south polar region. It also conducted in-situ lunar surface and near-surface plasma studies and recorded lunar soil variations in the south-polar region for the first time.

The Chandrayaan-4 mission aims to collect 3 kilograms of lunar samples from a water-ice-rich region near the Moon’s south pole and deliver the samples to Earth. This mission will demonstrate the essential technologies required for docking/decoupling, landing, surface sampling, drilling mechanism, sample storage cartridge, sample transfer, and take-off from the lunar surface after collecting surface samples and safely returning them to Earth.

Details of the Chandrayaan-4 mission

The mission is expected to be completed within 36 months of approval from industry and academia, and all critical technologies will be developed in-house. Therefore, the project will require significant participation from the Indian industry and academic research communities.

The total requirement for the Chandrayaan-4 demonstration mission is about $253 million. The cost includes developing and realising the spacecraft, two LVM3 launch vehicles, support for the outer deep space network and special testing. ISRO will be responsible for spacecraft development and launch.

A technically challenging mission

The mission architecture includes five spacecraft modules requiring two launches from ISRO’s most powerful rocket, LVM-3. The first of the two launches will carry the landing module and the sample collection vehicle, while the second two launches will take the transport module and the return module, which will be placed in lunar orbit. The sample collection vehicle will then lift off from the lunar surface and carry this valuable cargo to the reentry module, which will return to Earth for a safe landing.

The most challenging task for the mission is to launch two spacecraft into orbit. To practice this manoeuvre, ISRO will launch a $14 million space docking facility called Spadex later this year or early 2025.

Why is it essential to study samples from the Moon’s south pole?

Samples from various locations on the Moon are needed to fully understand the complex origin and history of the Earth-Moon system. The Apollo and Luna station samples revolutionised our understanding of the Moon’s origin. Still, they were taken from similar geological areas and are, therefore, not representative of the entire Moon.

In December 2020, China’s Chang’e-5 lunar mission successfully delivered samples from a geologically young region of the Moon that revealed many aspects of the Moon, especially its complex thermal history. In this context, India’s Chandrayaan-4 mission, focuses on the south polar region, is significant. This region has abundant water and ice for life support for future lunar bases and rocket fuel.

What comes after Chandrayaan-4?

Chandrayaan-4 is expected to be followed by a joint ISRO and Japan Aerospace Exploration Agency (JAXA) mission to explore permanently shadowed craters called Lunar Polar Exploration Mission (LUPEX). This is currently labelled as Chandrayaan-5 in India.

As part of the LUPEX mission, India will provide the landing module part of the payload and oversee the mission’s planning. Japan will provide the launch vehicle, various payloads and the lunar rover.

It will be a weighty mission – the lunar rover on Chandrayaan-3 weighed only 27kg, while on Chandrayaan-5 it will weigh 350kg. The payload will include GPR, spectrometers, and water analysis instruments. India and Japan will both contribute these articles. The LUPEX mission is scheduled for 2028 or 2029 and will be launched on Japan’s H3 rocket.