Mars is a dangerous place for rovers. Several vehicles sent from Earth have met an untimely end on the Red Planet. But two have survived through to today — the Opportunity and Curiosity rovers, and both are methodically exploring the Martian landscape.

During the course of that exploration, Curiosity has picked up a few dings and dents on its 50cm-diameter aluminium wheels. Since it landed on Mars in August 2012, it’s travelled nearly five kilometres across rocky terrain. During the last quarter of 2013, however, the damage sustained to its wheels accelerated, and now Nasa is being-extra careful about the ground that the one-tonne rover is driving over.

“The wheels can sustain significant damage without impairing the rover’s ability to drive,” explained engineer Jim Erickson of Nasa’s JPL, “However, we would like to understand the impact that this terrain type has on the wheels, to help with planning future drives.”

Engineers now check the condition of the rover’s wheels on a regular basis, and select routes and driving methods that should cause minimum possible disruption to the rover’s long-term health.

With that in mind, its operators are eyeing up a sand dune that’s blocking Curiosity’s path into a small valley called the “Dingo Gap” that contains far fewer rocks that may damage the wheels. If the rover can successfully climb the metre-tall dune, its way will be a lot clearer as it heads towards future targets.

Climbing the dune, however, is a riskier endeavour than it might seem. Curiosity’s sister rover, Opportunity, nearly got stuck in a dirt pile named “Purgatory Dune” in 2005, and the Sprit rover was lost in a similar way in 2009.

As such, NASA is playing this one very carefully, testing the sand’s consistency by pressing the rover’s wheels into the base of the dune. The include should easily be manageable, but there is a fear that rocks hidden below the sand could damage the wheels further.

For now, Curiosity has merely been commanded to climb part-way up the slope to see how it goes. If there are no significant hitches, it will go the rest of the way and over the crest of the dune.

Its next target is a drilling location named KMS-9, where there’s some freshly exposed bedrock that Curiosity will probe for traces of carbon chemistry. The Gale crater is believed to have hosted microbial life billions of years ago in a freshwater lake, and if that’s the case then some traces of that life may remain.

The eventual goal is to reach the foothills of the 5.5km-high mountain at the centre of the crater — Aeolis Mons. Though that goal is many months, and several kilometres, away.