NASA Curiosity Rover Wheel Photos Reveal Larger-Than-Expected Hole, Inner Mechanisms

The Mars Hand Lens Imager does not lie. RAW photos uploaded to the Mars Science Laboratory website show the wheels are in far worse shape now, with sections of the tire sidewall having completely collapsed. The images, captured on Monday, March 23, Sol 4844, offer the closest look yet at just how severely Gale Crater has punished Curiosity's middle right wheel over more than a decade of continuous driving.

New photos taken by Curiosity's Mars Hand Lens Imager (MAHLI) reveal that the rover's epic journey has taken a toll on the robot's middle right wheel, with several large tears in the wheel's heavily scratched tire, including one particularly large hole that reveals the wheel's inner mechanisms. The close-up frames show a zigzag tread pattern fractured along its length, with missing segments and visible deformation that go well beyond cosmetic wear.

From a photography standpoint, this is exactly the kind of imagery that MAHLI was designed to deliver: macro-level detail that no Earth-based telescope could ever provide. The MastCam, Mars Hand Lens Imager (MAHLI), and Mars Descent Imager (MARDI) cameras were developed by Malin Space Science Systems and share common design components, including 1600 x 1200 charge-coupled device (CCDs). Mounted on the rover's robotic arm, MAHLI can position itself against specific targets with the precision of a macro lens on a focus rail, and the wheel damage images demonstrate exactly why that capability matters for long-duration mission monitoring.

It is currently unclear when these holes first emerged or if any of the rover's other wheels have suffered similar damage. What is clear from the Sol 4844 imagery is that the deterioration has accelerated. Curiosity has six wheels, and it is thought that the most damaged one is its middle-right wheel; some of the photos show wheels that are in much better shape.

The damage is not happening without a response from the ground team. NASA assembled a Wheel Wear Tiger Team, a crisis problem-solving tradition that goes back to Apollo 13. In 2017, the team uploaded a traction control algorithm from Earth that adjusts each wheel's speed in real time based on terrain, reducing force on the front wheels by 20%, and they rerouted the rover to softer ground and started driving backward when possible, because pulling wheels over rocks produces less force than pushing them into rocks. Engineers also log every crack methodically: "They note down each and every crack and then, in order to minimise damage to the wheels, experts keep an eye out for dangerous spots on the planet for the rover to avoid."

That surveillance happens on a fixed schedule. "Every 3,330 feet (1,000 meters), the Curiosity Rover uses its cameras to inspect its wheels, and each time it gets slightly worse." It is a relentless, incremental deterioration documented frame by frame across years of Martian driving.

Curiosity first touched down on Mars on Aug. 5, 2012, and has lasted 4,323 Martian days, or Sols, on the Red Planet, traveling more than 20 miles (32 kilometers) around the Gale Crater. The original mission plan called for two years. What the Sol 4844 wheel images actually show is what genuine longevity costs in aluminum and tread, documented with the same precision NASA uses to study Martian geology.

After a certain amount of tread comes off, NASA has a plan to find a sharp rock on Mars and use it to rip out the damaged inner section of Curiosity's wheel. Whether that intervention is approaching is a question the engineering team has not yet answered publicly, but the imagery from March 23 makes it one worth asking soon.