Reinventing the wheel is generally considered a bad idea. But engineers at NASA’s Glenn Research Center in Cleveland are doing just that — designing an entirely new wheel that will give upcoming Mars rovers the ability to drive long distances on the Red Planet without sustaining damage.
The wheel, made of an ultra-flexible metal mesh, is designed to deform as it rolls over sharp rocks and other irregular features on the Martian surface — and then snap back to its original shape.
NASA hopes the wheel will be more durable than the wheels on NASA’s Curiosity rover. Selfies snapped by Curiosity in 2013 showed that the treads on the rover’s aluminum wheels had sustained significant damage after only about a year on Mars.
The idea of a chain mail-like tire isn’t new. In 2009, NASA worked with Goodyear to create a wheel made of mesh woven from hundreds of coiled steel wires. The Spring Tire, as the wheel was dubbed, provided good traction and durability on soft sands and rock. But there was a problem: In tests at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, the steel wire mesh dented as it rolled over a simulated Martian landscape.
About five years ago, researchers at NASA Glenn decided to create a mesh wheel made not of steel but of nickel-titanium, a so-called “shape memory alloy.” Such alloys “remember” their original shape and spring back immediately after deforming, meaning they retain their original shape and performance.
“This particular material doesn’t deform like conventional materials,” Santo Padula, a materials scientist at NASA Glenn, said in a video released by the agency. “We can actually deform this all the way down to the axle and have it return to shape, which we could never even contemplate in a conventional metal system."
The chain mail wheel performed “impressively” in experiments conducted at JPL's Mars Life Test Facility, NASA said. The wheels are not earmarked for a specific mission but could be used on future expeditions like the proposed Mars Sample Return mission, which could launch in the mid-2020s.