If humans finally colonize the Moon, lunar caves formed from primeval volcanic activity could provide shelter from cosmic radiation and extreme temperatures. But how does one go about safely exploring these uncharted caves before they venture in?
Enter a team of scientists from South Korea who have built a simple rover prototype that can traverse rough terrain. What’s truly special about this robot are its sturdy wheels, made of flexible metal strips woven together into a helix-like pattern that give it the ability to expand and contract like a piece of kinetic art.
“Experimental results show successful traversal of 200-millimeter [7.8 inches] obstacles, stable mobility on rocky and lunar soil simulant surfaces, and resilience to drop impacts simulating a 100-meter [328 feet] descent under lunar gravity,” write the scientists in a new paper published in the journal Science Robotics.
Because it can grow from nine to 19.6 inches in diameter, a rover with these wheels is able to distribute weight more evenly along its body. The result is a bot robust enough to navigate tricky cavern landscapes, along with the ability to fit into tight spaces in its smallest configuration. Other robots have used hinges or “origami-inspired folds” which can be vulnerable to lunar surface hazards, according to the paper.
The scientists demonstrated the wheel’s robustness and ability to travel around or over obstacles by having the rover explore a real cave here on Earth. They also used a drone to drop it in the air, and blasted it with fire and cold. The metal in the wheel itself is made from light weight carbon steel strips, making them tough but elastic.
“Consequently, the wheel could absorb impacts and navigate uneven terrain while remaining robust under extreme lunar conditions,” the paper reads.
For a future mission to the Moon, the team envisions a large rover carrying multiple smaller rovers with these special wheels and deploying them at the opening of a lunar pit.
“Although the explorers remain compact when stowed, the large diameter of the deployable wheels is expected to increase the ground contact area, thereby improving traction on thick dust and uneven slopes,” the paper reads. “This capability would allow the explorers to navigate challenging pit entrance terrain safely.”
The large rover would then directly drop these smaller rovers inside the lunar pit leading to a cave, with the “wheels’ elasticity and impact capacity” serving as shock absorbers.
“The results highlighted the deployable wheel’s ability to combine adaptability, durability, and operational efficiency, making it a promising solution for diverse and challenging mission scenarios,” the paper reads.
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