Chandrayaan-4, India's upcoming lunar mission, has been officially approved and is set to be a significant advancement in the country's space exploration efforts.

India's Chandrayaan-4 mission, scheduled for launch in 2025, will involve two separate launches due to its total mass of approximately 9,200 kg. This mission aims to soft land near the Moon's south pole, collect lunar samples, and return them to Earth for analysis.

Given that the Indian Space Research Organisation (ISRO) currently has a payload capacity of about 4,500 kg to Geosynchronous Transfer Orbit (GTO) using the LVM-3 launch vehicle, the mission will necessitate launching two modules together in one stack and three modules in another stack, with a planned one-month gap between these launches.

“We have completed the configuration design and now the design of various subsystems is ongoing,” Narayanan said in an interview with TOI, adding that the mission architecture involves multiple docking and undocking manoeuvres in both Earth and lunar orbits.

The mission will involve the deployment of five modules that will be launched in two separate stacks due to the spacecraft's total mass of approximately 9,200 kg, which exceeds the current payload capacity of ISRO's launch vehicles. The mission will utilise two LVM-3 rockets to deliver the modules into orbit.

The first launch will carry two modules, while the second will transport three modules, with an estimated one-month gap between launches. After both launches, the modules will dock in Earth orbit. This initial docking phase is crucial for assembling the spacecraft before it embarks on its journey to the Moon. Following docking, a propulsion module will facilitate the transfer of four modules to lunar orbit, separating at approximately 1,00,000 km from the Moon.

After sample collection, one module will return and dock with the remaining modules in lunar orbit, the sample will be transferred to a re-entry module and the re-entry module will return to Earth with the samples.

LUPEX Mission

The Lunar Polar Exploration Mission (LUPEX), designated as Chandrayaan-5 by India, represents a significant advancement in lunar exploration, particularly focusing on the Moon's polar regions. LUPEX aims not only to enhance our understanding of the Moon's polar regions but also to lay the groundwork for future human exploration missions. By demonstrating advanced technologies required for landing larger payloads on the Moon, this mission is a critical step towards India's goal of sending humans to the lunar surface by 2040.

The total landing mass of the spacecraft is projected to be 6,200 kg. This marks a substantial increase compared to previous missions, reflecting the mission's enhanced capabilities and objectives. The rover intended for LUPEX will weigh between 350 kg and 400 kg, which is approximately 14 times heavier than the Pragyan rover used in Chandrayaan-3, which weighed only 26 kg.

The mission is a joint effort between India and Japan. Japan will handle the development and operation of both the launch vehicle and the rover, while ISRO will be responsible for the lander. In addition to Indian and Japanese scientific instruments, LUPEX will carry payloads from American and European sources, enhancing its research capabilities.

The LUPEX mission will counter engineering challenges. The increased weight of the lander necessitates advanced engineering solutions. ISRO is developing new propulsion systems and descent algorithms to manage the complexities associated with landing such a heavy payload on the lunar surface. This includes terrain navigation systems to avoid obstacles during descent. The lander's design allows for a greater payload capacity, enabling it to carry sophisticated scientific instruments for detailed studies of the lunar surface. This includes capabilities for drilling into the lunar surface to analyse ice and other volatiles.

Here are the key details regarding the mission:

The Chandrayaan-4 spacecraft will consist of five modules designed for various functions, including landing, sample collection, and safe return to Earth. This is an increase from the three modules used in Chandrayaan-3.

The mission will necessitate multiple dockings, both in Earth's orbit and lunar orbit. The initial docking will occur in Earth's orbit after two separate launches using LVM-3 vehicles. This will involve launching two modules in one stack and three in another, spaced about a month apart.

The primary goal of Chandrayaan-4 is to achieve a soft landing near the Moon's south pole, collect lunar samples, and return them to Earth for analysis. This mission aims to enhance India's capabilities in lunar exploration and sample return technology.

The mission will demonstrate critical technologies such as high-capacity propulsion systems, robotic arms for sample collection, and advanced docking techniques. These technologies are essential for future manned missions to the Moon, planned for 2040.

Chandrayaan-4 is also linked with the Lunar Polar Exploration Mission (LUPEX), a collaborative effort between ISRO and the Japan Aerospace Exploration Agency (JAXA). This partnership aims to further explore lunar polar regions and enhance scientific understanding through shared resources and expertise.

The mission has been allocated a budget of approximately ₹2,104.06 crore (about $240 million) and is expected to be completed within 36 months of its approval.

The launches are projected to take place between 2026 and 2028, with detailed planning already underway for the necessary technologies and infrastructure.

Chandrayaan-4 represents a crucial step in India's ambition to establish itself as a leader in space exploration, particularly in lunar missions.

TOI