India, Japan to begin design phase for Chandrayaan-5 mission

Indian and Japanese space agencies working on the Chandrayaan-5 project, which aims to explore the Moon's surface for water, will shortly begin the preliminary design process for the lander and rover.

According to Asoh Dai, Project Manager, LUPEX, at the Japan Aerospace Exploration Agency (JAXA), “The instrument selections have been done, the engineering model testing is almost done and both India and Japan are entering the preliminary design phase,” as reported by the Indian Express.

Chandrayaan-5, also called LUPEX (Lunar Polar Exploration), is a collaborative mission between ISRO and JAXA aimed at investigating the presence of water and water-ice on the lunar surface and subsurface. Weighing 6.5 tonnes, the mission is scheduled for launch aboard Japan’s H3 rocket around 2027–28.

JAXA’s rover will identify water-rich regions on the Moon, collect nearby soil or regolith samples by drilling, and conduct on-site tests to analyze water content, quality, and other characteristics.

The Indian Cabinet approved the Chandrayaan-5 mission in March this year, following India’s historic Chandrayaan-3 soft landing near the lunar south pole. Before Chandrayaan-5, ISRO plans to launch Chandrayaan-4, a sample return mission designed to collect lunar material and bring it back to Earth for detailed mineral analysis.

Speaking at the Global Space Exploration Conference in New Delhi last week, Dai shared insights about the Chandrayaan-5 mission. ISRO chief V Narayanan announced that the mission is planned to last around 3.5 months or 100 days.

ISRO is responsible for developing the lander, while JAXA is building the 350-kg rover. The mission will carry seven scientific instruments, with contributions from both the European Space Agency (ESA) and NASA.

ESA is designing the mass spectrometer, and NASA is working on the neutron spectrometers—both instruments are still in the design phase, Indian Express reported.

Dai mentioned that one of the seven scientific instruments on board Chandrayaan-5 will be a large unit equipped with four sensors—one developed by ISRO and the remaining three by JAXA.

He explained that the rover, designed and programmed by JAXA, will be capable of navigating the lunar terrain, including slopes with inclinations up to 25 degrees. According to him, the rover's battery charging schedule has been carefully planned to occur once before and once after sample collection, describing it as a highly complex process.

Dai also indicated that, if the LUPEX mission proceeds as intended, there is a possibility of extending the mission to explore the Moon’s far side. The mission life could potentially be lengthened by an additional year. Meanwhile, a JAXA delegation is visiting ISRO's headquarters in Bengaluru this week for further discussions.