DAEJEON, SOUTH KOREA – A joint research team from the Korea Advanced Institute of Science and Technology (KAIST) and the Unmanned Exploration Laboratory (UEL) has developed a transformative wheel capable of navigating the Moon's most extreme terrains, including steep lunar pits and lava tubes.
The study presents a novel "origami-inspired" deployable airless wheel that can significantly expand its diameter to traverse obstacles that would trap traditional rovers. The research was published in the December issue of Science Robotics.
The Challenge: Small Rovers vs. Big Obstacles Lunar lava tubes and pits are prime candidates for future human habitats due to their natural shielding from cosmic radiation and extreme temperature fluctuations, but accessing them is perilous. Deploying a swarm of small, independent rovers can be an effective strategy to mitigate the risks associated with a single large rover. This strategy ensures mission continuity through redundancy; even if some units fail, the remaining rovers can complete the exploration.
However, small rovers face an inherent physical limitation: their compact wheel size severely restricts their ability to traverse steep, rugged terrains like lunar pit entrances. While variable-diameter wheels could theoretically solve this by offering high traversability on demand, creating such a system for the Moon has been a formidable challenge. Designing a lightweight transformable wheel that can withstand the harsh lunar environment—specifically the abrasive dust and the vacuum that causes metal parts to fuse ("cold welding")—has remained a significant engineering hurdle.
A Transformable Wheel for Extreme Environments To conquer these obstacles, a research team, led by Professor Dae-Young Lee from KAIST's Department of Aerospace Engineering, developed a new type of compliant wheel that eliminates complex mechanical joints. By applying the structural principles of the "Da Vinci bridge" combined with origami design, the team created a wheel that uses the flexibility of its materials to transform.
Capable of expanding from a compact 230 mm to 500 mm in diameter, the wheel allows compact rovers to maintain a low profile during transport, yet scale significant obstacles once deployed. Crucially, by utilizing a specialized elastic metal frame and fabric tensioners instead of traditional hinges, the design ensures reliable operation in the harsh lunar environment, effectively resisting the risks of cold welding and mechanical failure caused by fine dust.
The team rigorously tested the wheel's capabilities using artificial lunar soil (simulants). The wheel demonstrated superior traction on loose slopes and proved its structural integrity by withstanding a drop impact equivalent to a 100-meter fall in lunar gravity.
Scientific and Engineering Significance The project brought together experts from major Korean space institutes to validate the technology's potential. Prof. Lee highlighted the wheel as a practical and reliable solution for navigating the Moon's most difficult terrains, expressing optimism that this unique technology would position the team as leaders in future lunar missions despite remaining challenges involving communication and power.
From a scientific perspective, Dr. Chae Kyung Sim, Head of the Planetary Science Group at KASI (Korea Astronomy and Space Science Institute), emphasized the value of lunar pits as "natural geological heritages," noting that this research significantly lowers the technical barriers to accessing these sites and brings actual exploration missions closer to reality. Furthermore, Dr. Jongtae Jang, Principal Researcher at KARI (Korea Aerospace Research Institute), underscored the engineering rigor behind the design, explaining that the wheel was meticulously optimized and validated using mathematical thermal models to endure the Moon's extreme 300-degree temperature fluctuations.
About KAIST KAIST is the first and top science and technology university in Korea. KAIST has been the gateway to advanced science and technology, innovation, and entrepreneurship, and our graduates have been key ingredients behind Korea's innovations.
About UEL UEL(Unmanned Exploration Laboratory), inc. has cutting edge technology about planetary exploration mobility robotics in the Republic of Korea. UEL provides unmanned exploration systems from design and manufacturing the mobility platforms to perform the rover missions on Earth, the Moon, and beyond.
Journal Reference Science Robotics
DOI 10.1126/scirobotics.adx2549
Media Source https://www.dropbox.com/scl/fo/40m95eh4d232fu956a82z/ALc7CtNiE0CwB6qNjTSWO5k?rlkey=wr33fdngvx9wltqbad1aawcab&dl=0
