Mars isn't a soft and cushy place to tread. The landscape is strewn with rocks, and all those sharp bits are taking a toll on NASA's Curiosity rover. The rover's wheels are made from solid aluminum, which is pretty tough stuff, but a new image released Tuesday shows breaks in some of the raised wheel treads.

NASA spotted the breaks on March 19 during a routine check of the wheels. The last check took place on Jan. 27, so the breaks are relatively fresh. The wheel-tread issue is nothing new, but the current extent of the damage is notable. NASA images from early 2016 showed just cracks in the wheels.

Curiosity has rolled across nearly 10 miles (16 kilometers) of Mars since landing in mid-2012. Dents and holes started to appear as early as 2013.

Curiosity Project Manager Jim Erickson says the left middle wheel is "nearing a wheel-wear milestone," but "all six wheels have more than enough working lifespan remaining to get the vehicle to all destinations planned for the mission."

The rover is currently in residence in an area known as the Murray formation in the region of Mount Sharp. The fascinating mountain is located in the Gale crater, Curiosity's landing site.

NASA has plans for the rover to travel at least 3.7 miles (6 kilometers) more as it studies Mount Sharp's lower rock layers. The space agency hopes to minimize further damage by avoiding particularly rough terrain along the route.

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