By R Anil Kumar
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ISRO and JAXA Gear Up for Joint Chandrayaan-5 / LUPEX Mission in the Technical Interface Meet
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Chandrayaan-5, also known as LUPEX (Lunar Polar Exploration), is a joint project between ISRO and JAXA to study water and water-ice both on the lunar surface and the subsurface. Weighing 6.5 tonnes, it is proposed to lift off on a Japanese rocket, H3, sometime in 2027-28
Bengaluru. During May 13-14, 2025, ISRO and JAXA, the space agency of Japan, jointly conducted the third face-to-face Technical Interface Meeting (TIM-3), towards the Chandrayaan-5/LUPEX mission, in ISRO Headquarters, Bengaluru.
The meeting was attended by senior officials, project executives, and technical team members from ISRO, JAXA, and the Mitsubishi Heavy Industries (MHI), Japan.
Following the legacy of Chandrayaan-1, Chandrayaan-2 (orbiter-based lunar exploration), Chandrayaan-3 (lander-rover based in-situ exploration) and the forthcoming Chandrayaan-4 (India’s first lunar sample return mission), the Chandrayaan-5 / LUPEX (LUnar Polar EXploration) mission will be the fifth mission in the Chandrayaan series of lunar missions, in collaboration with JAXA, to study the lunar volatile materials, including lunar water, in the vicinity of a Permanently Shadowed Region (PSR) in the lunar South pole.
The mission will be launched by JAXA onboard its H3-24L launch vehicle, carrying the ISRO-made lunar lander, which will carry the MHI, Japan-made lunar rover.
ISRO, apart from developing the lunar lander, is also responsible for developing a few scientific instruments for the mission. The scientific instruments for this mission would be contributed by ISRO, JAXA, ESA and NASA, all thematically connected with the exploration and in-situ analysis of the volatiles reserved in the lunar polar region.
The approval for the Chandrayaan-5 / LUPEX mission was received from Government of India on March 10, 2025, in the form of financial sanction.
During the meeting, Shri M. Ganesh Pillai, Scientific Secretary, ISRO congratulated both the teams for the technical achievements so far, and emphasized on the importance of the collaborative endeavour for the scientific and technical aspects of the mission.
Dr. Tirtha Pratim Das, Director, Science Programme Office, ISRO Headquarters, briefed about the major milestones achieved in terms of the landing site selection, payload optimization, mission design, as well as the ground segment and communication aspects.
Shri G Ravi Chandra Babu, study team leader of Chandrayaan-5/LUPEX, briefed about the technical configurations arrived. He emphasized on the need for the clear definition of the milestones, timeline and deliverables of the project.
Mr. Dai-Asoh, JAXA, during his opening address, briefed about the technical progress made towards the development of the rover and the interfaces related.
The two days face-to-face meeting deliberated on the various technical interfaces, joint mission implementation plan, as well as the potential landing sites for the mission.
The Chandrayaan-5 / LUPEX missions will be one of the major short-term milestones in India’s lunar exploration odyssey, which envisions Indian Gaganyatris (astronauts) landing on the Moon by year 2040.
About Chandrayaan 5 mission
Chandrayaan-5, also known as LUPEX (Lunar Polar Exploration), is a joint project between ISRO and JAXA to study water and water-ice both on the lunar surface and the subsurface. Weighing 6.5 tonnes, it is proposed to lift off on a Japanese rocket, H3, sometime in 2027-28
India has formally approved the joint ISRO-JAXA Chandrayaan 5 (LUPEX) mission to study water ice on the Moon’s south pole.
The water-hunting mission of LUPEX
The Chandrayaan 5 lander carrying the LUPEX rover on top of it will launch on Japan’s H3 rocket by end of decade, following India’s launch of Chandrayaan 4 which is targeted by 2028. The ~6,000-kilogram ISRO-developed Chandrayaan 5 lander will deploy the JAXA-provided ~350-kilogram LUPEX rover on the Moon’s south pole to directly study the nature, abundance, and accessibility of water ice. As part of its exploration spanning at least 3.5 months, the LUPEX rover will enter permanently shadowed regions seeking water ice and other such volatiles.
In terms of hardware development, JAXA and Mitsubishi have been validating the LUPEX rover design through a series of tests using qualification and engineering models. Engineering models for several rover instruments have also been built and tested. To safely and precisely land LUPEX amid the dangerously rocky terrain at the Moon’s south pole, ISRO is building the Chandrayaan 5 lander with input from both Chandrayaan 3’s success and that of JAXA’s SLIM lander. LUPEX builds on the previous Indo-Japanese collaboration of ISRO’s Chandrayaan 2 orbiter helping JAXA nail SLIM’s goal of precision lunar landing.
Landing site selection studies for LUPEX have been ongoing, feeding into as well as building on ISRO’s ongoing aid to NASA for planning crewed Artemis missions. A 2024 IAC talk by Chandrayaan 3’s Project Director Palanivel Veeramuthuvel suggests that Chandrayaan 5’s landing site could be 89.45°S, 222.85°E, which lies on an elevated ridge connecting the large Shackleton and de Gerlache craters. A key criteria for selecting Chandrayaan 5’s landing site is that it should have several 100-meter-scale permanently shadowed regions nearby so that the LUPEX rover can directly study any potential water ice and other volatile deposits they might host.
LUPEX will power through one of the harshest planetary environments in the solar system. Between cryogenic temperatures during major investigations, a rocky terrain riddled with steep slopes, and a near-horizon Sun causing long, moving shadows that the rover needs to keep avoiding, we’re sending LUPEX to lunar hell. Despite facing much colder temperatures than NASA’s flagship Mars missions, LUPEX is not currently planned to have a radioisotope heater unit (RHU) for warmth. Instead, the solar-powered rover will rely on its battery and heat pipes to keep itself from freezing. LUPEX will periodically park at pre-identified high-altitude polar spots during the mission where local nights last only 3 to 5 Earth days instead of the longer 14 Earth days worth of equatorial lunar nights.
