An anonymous reader writes: The folks in charge of the Mars rover Curiosity have been trying to solve an increasingly urgent problem: what to do about unexpected wheel damage. The team knew from the start that wear and tear on the wheels would slowly accumulate, but they've been surprised at how quickly the wheels have degraded over the past year. Emily Lakdawalla at the Planetary Society blog has posted a detailed report on the team's conclusions as to what's causing the damage and how they can mitigate it going forward. Quoting: "The tears result from fatigue. You know how if you bend a metal paper clip back and forth repeatedly, it eventually snaps? Well, when the wheels are driving over a very hard rock surface — one with no sand — the thin skin of the wheels repeatedly bends. The wheels were designed to bend quite a lot, and return to their original shape. But the repeated bending and straightening is fatiguing the skin, causing it to fracture in a brittle way. The bending doesn't happen (or doesn't happen as much) if the ground gives way under the rover's weight, as it does if it's got the slightest coating of sand on top of rock. It only happens when the ground is utterly impervious to the rover's weight — hard bedrock. The stresses from metal fatigue are highest near the tips of the chevron features, and indeed a lot of tears seem to initiate close to the chevron features."