The Indian Space Research Organisation (ISRO) is planning to team up with the Japan Aerospace Exploration Agency (JAXA) to build a large lander for the forthcoming Lunar Polar Exploration (LUPEX) mission. This mission, also known as Chandrayaan-5, is expected to launch in 2028. The new lander will be designed to carry a 350 kg rover, which is 14 times heavier than the Pragyaan rover used in the Chandrayaan-3 mission. This significant increase in the rover’s weight marks a major leap in ISRO’s ability to explore the Moon.
Interestingly, the lunar south pole has drawn a lot of scientific interest because it may contain water ice deposits and the LUPEX mission aims to explore this area. A key part of the mission is the heavy lander module that ISRO is working on. This lander will be equipped with advanced features to handle the larger payload, such as new engines, fuel tanks, control systems and landing gear. The main goal of the mission is to demonstrate technologies needed for future lunar landings, such as carrying more cargo, analysing samples on the Moon, longer stays on the lunar surface and landing with greater precision.
The Chandrayaan-3 mission, launched in 2023, was a follow-up to the Chandrayaan-2 mission with the aim of demonstrating the ability to safely land and operate a rover on the Moon’s surface. The lander, Vikram, was built to carry a payload of 26 kg, which is much lighter compared to the 350 kg rover planned for the LUPEX mission. The Chandrayaan-3 spacecraft included such advanced technology as a Laser Doppler Velocimeter, a Hazard Detection and Avoidance Camera and Throttleable Liquid Engines. Thanks to these systems, the lander successfully deployed the Pragyaan rover for on-site chemical analysis and achieved a smooth landing on the Moon.
“One of the biggest advantages of a heavier lander is its ability to carry larger and more advanced scientific tools. The 350 kg rover for the LUPEX mission will be able to transport more complex equipment, allowing for more detailed scientific studies. With this increased capacity, the mission can gather and analyse data more thoroughly, leading to better scientific results. On the other hand a heavier lander module offers greater stability during landing. Its increased weight helps maintain a steady descent, reducing the risk of tipping over upon touchdown. This stability is crucial for accurate landings, especially in such challenging areas as the lunar south pole,” remarked space and aerospace expert Girish Linganna.
Experts point out that heavier lander modules can carry bigger power sources, such as larger solar panels or batteries, which allow them to operate longer on the Moon’s surface. This extended operation time enables the mission to perform more scientific experiments and gather more data, boosting its overall success. The Moon experiences extreme temperature changes, with daytime highs of up to 127°C and nighttime lows of -173°C. To protect delicate instruments from these harsh conditions a heavier lander can be equipped with stronger thermal management systems.
“With the increased payload capacity of heavier lander modules, redundant systems and backup components can be included, boosting the mission’s reliability. This redundancy is crucial for longer missions because the failure of one component could jeopardise the entire operation,” observed Linganna
The LUPEX lander will carry far more scientific payloads than its predecessors, significantly enhancing its ability to conduct in-depth exploration of the Moon’s polar regions. The decision to build a 26-ton lander was driven by the need to carry larger payloads, which include advanced scientific instruments, a highly sophisticated rover, and extended power systems capable of surviving the harsh conditions of the lunar night, which lasts up to 14 Earth days.
“The lander’s larger size will allow for more complex scientific investigations, including drilling into the lunar surface to analyse ice and volatiles, mapping mineral distributions, and studying the Moon’s geology. This represents a major leap forward compared to the Chandrayaan-3 mission, which was designed to validate India’s ability to perform soft landings. While Vikram was instrumental in demonstrating India’s technical prowess, the LUPEX lander must perform far more complex tasks, making its increased weight and size crucial for mission success,” remarked Srimathy Kesan, founder and CEO of Space Kidz India, which is into design, fabrication and launch of small satellites, spacecraft and ground systems.
Landing such a large vehicle on the lunar surface presents unique engineering challenges. For comparison, the Chandrayaan-3 lander, with a weight of under two tons, required relatively moderate propulsion systems and a simple descent algorithm to achieve a soft landing. For the LUPEX lander, which weighs 26 tons, the engineering hurdles are significantly greater.
“To control the descent of such a massive payload, ISRO is developing advanced propulsion systems and descent algorithms capable of managing the increased weight. The lander will also be equipped with terrain navigation systems that allow it to identify and avoid obstacles like boulders and craters, ensuring a precise and safe landing near the lunar South Pole. These systems will be coupled with high-resolution sensors that guide the lander through its final descent, drawing on ISRO’s successful track record with the Chandrayaan-3 mission. Additionally, the increased gravitational pull on the heavy lander will require more fuel for deceleration, leading to the need for efficient fuel management systems and precise thrust control. To address this, ISRO is exploring innovative propulsion technologies that can handle the complex dynamics of landing a 26,000 kg lander in the Moon’s low-gravity environment,” explained Kesan.
The module is indeed heavy and many other modules that were developed were lightweight. Take the case of NASA's Peregrine Mission 1 lunar lander, built by Astrobotic, weighed 1,283 kg (2,829 lb) and could carry a payload of up to 90 kg (198 lb) to the Moon’s surface. It was designed to deliver scientific instruments, technology demonstrations and other payloads for various customers, including NASA and commercial entities. However, during its launch in January 2024, Peregrine Mission 1 experienced a propellant leak and was unable to land on the Moon. “when compared the Blue Origin’s Blue Moon is a lunar lander designed to transport cargo and eventually astronauts to the Moon. Developed for NASA’s Artemis programme, specifically Artemis V, will launch no earlier than 2029. The lander has two versions—Mark 1 for cargo, carrying up to 3 tons and Mark 2 for crew. Weighing approximately 16.5 tons fully fuelled, Blue Moon is powered by liquid hydrogen and liquid oxygen propellants. It is a key component in establishing a sustainable human presence on the Moon,” pointed out Linganna.
The ESA’s Lunar I-Hab module is a habitat for astronauts on the Lunar Gateway, a future space station orbiting the Moon. Offering 10 cubic metres of living space, it will support 90-day missions and host scientific experiments. Weighing 10,000 kg, it will be launched by Artemis IV, possibly in 2029 or later. Developed by the ESA with JAXA’s support, the I-Hab ensures a safe environment, showcasing international collaboration for sustained lunar exploration.