Scientists at NASA have reported a concerning sign from the surface of the Red Planet based on images taken by the Mars Curiosity rover. It appears that the rover has developed cracks in its wheels after its 10-mile journey on the surface of Mars, and that could limit its future missions, although NASA says it won’t jeopardize the overall mission.

Curiosity has been trekking Mars since 2012, and it’s not unusual to see wear and tear start to develop after that period of time in the harsh environment, but these breaks have been significant and developed rapidly. Engineers noticed them during a routine check of the wheels on March 19, even though they weren’t there during the last check in late January.

Fortunately, all six wheels likely have enough lifespan for the rover to complete its main mission and get to all planned destinations, but time may be running out for Curiosity as it explores the Murray formation near Mount Sharp.

“The rover is climbing to sequentially higher and younger layers of lower Mount Sharp to investigate how the region’s ancient climate changed billions of years ago,” according to a NASA statement. “Clues about environmental conditions are recorded in the rock layers. During its first year on Mars, the mission succeeded at its main goal by finding that the region once offered environmental conditions favorable for microbial life, if Mars has ever hosted life. The conditions in long-lived ancient freshwater Martian lake environments included all of the key chemical elements needed for life as we know it, plus a chemical source of energy that is used by many microbes on Earth.”