Mars is a hostile place, and as the latest images beamed back from the surface show, the Curiosity Mars rover is really starting to suffer the effects of an extended stay there.
The 16-inch wide solid aluminum wheels that allow Curiosity to travel across the surface of Mars are breaking. Images captured on March 19 show two fresh breaks in the raised treads of the left middle wheel that were not present when the wheels were last checked on January 27.
The good news is, such wear is expected even if it was initially underestimated back in 2013 after less than a year on the planet's surface. It is not bad enough, or progressing quickly enough, to force NASA to change Curiosity's travel plans. It's also worth pointing out the rover's journey will soon hit the 10 mile mark, which is an impressive achievement.
Curiosity is attempting to climb an area of Mount Sharp so as to help scientists back on Earth figure out how the climate changed a few billion years ago. In order to fulfill its current destination goals, Curiosity needs to travel at least another 3.7 miles.
In order to limit further damage to the wheels, NASA is attempting to map the rover's route around hazardous terrain whenever possible. Even so, Curiosity Project Manager Jim Erickson at NASA's Jet Propulsion Laboratory says that the latest breaks show the left middle wheel is "nearing a wheel-wear milestone."
If everything goes to plan, Curiosity will fulfill all of its current goals and still have some life left in its wheels to do further tasks. But at some point one or more of the wheels will break completely, turning Curiosity into a stationary Mars monitor that hopefully one day an astronaut can walk up to and get rolling once again.