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 …