Those wheels you’re looking at are 0.75 millimeters thick. That’s half the thickness of a US dime. Each one was carved from a single block of aluminum, and NASA sent six of them to Mars knowing they’d eventually shred. Curiosity was built for a 2-year mission. It landed in August 2012, and by December that year NASA had already extended the mission indefinitely. Thirteen years and 35.5 kilometers later, the rover is still going, but the wheels started cracking just 14 months in. The damage came faster than anyone at JPL predicted. Sharp embedded rocks were punching straight through the skin between the treads. So NASA assembled a Wheel Wear Tiger Team (a crisis problem-solving tradition that goes back to Apollo 13) and got to work. In 2017, they uploaded a traction control algorithm from Earth that adjusts each wheel’s speed in real time based on the terrain, reducing force on the front wheels by 20%. They rerouted the rover to softer ground and started driving backward when possible, because pulling wheels over rocks produces less force than pushing them into rocks. The wildest part: if enough treads snap off, Curiosity is designed to find a sharp rock on Mars and use it to deliberately rip out the damaged inner section of its own wheel. JPL tested this on a replica rover and found Curiosity can keep driving on just the outer third. They predict this won’t be needed until around 2034. Every 1,000 meters, the rover pulls over and uses the camera on its robotic arm to photograph its own wheels so engineers on Earth can count every crack. Each wheel also has tiny holes that spell “JPL” in Morse code, which Curiosity uses to measure distance by photographing its own tracks in the dirt. These photos directly changed the next rover. When NASA built Perseverance, engineers 3D-printed about 70 different tread designs before landing on 48 curved treads instead of Curiosity’s 24, with thicker skin. They tested the new wheels over 60 kilometers and got zero damage by Curiosity’s original failure definition. “A boring graph with no data on it,” as one JPL engineer put it. A $2.5 billion machine doing self-surgery with rocks on another planet because the mission outlasted its design by 6x.