Even robots do not live forever and NASA's Curiosity rover is not an exception.
Two of the raised treads on Curiosity's left middle wheel broke, as shown in a new image released by NASA during the routine check-up on March 19 using Mars Hands Lens Imager (MAHLI) camera on the rover's arm. The last routine check on the wheels was on Jan. 27.
Curiosity Rover's Wheels
The harsh Martian terrain is taking a toll on the rover's set of six wheels made of solid aluminum — each of these wheels measures 20 inches in diameter and 16 inches across.
The spokes inside the wheel are made of titanium.
Each is covered with 19 zigzag-shaped treads, called grousers, raised about a fourth of an inch from the wheel. The raised treads are designed to provide traction and balance for the rover to roll and climb on the rugged Martian environment.
Holes And Tears Worsened
Over time, the rover had suffered dents and holes from all the poking and pitching of planet's terrain.
These holes and tears have worsened since 2013 when Curiosity crossed the rock-studded terrain to the base of Mount Sharp near its 2012 landing site.
The discovered damage was the first on the raised treads on the supposed tough wheels. This is also one of the reasons why NASA is keeping a close watch over Curiosity.
Mission's Operations Not Affected
The Martian landscape, with rocks and bits of sharp objects strewn on the ground, is no soft bed for the hardworking rover.
It took almost five years for Curiosity rover to earn the mileage in its super-slow rolling over the gritty canyon and rock-studded terrain.
Based on longevity tests conducted with similar aluminum wheels on Earth, the broken treads on the rover's wheel has indicated that it has reached 60 percent of its productive life.
NASA scientists said the Martian rover has performed well in reaching all the geological layers as planned and will not affect the mission's operations. In fact, Curiosity has outlived its planned mission twice.
NASA said the rover has yet to cover some 3.7 miles (6 kilometers) to complete the mission. The agency is trying to minimize damage by choosing safer routes for Curiosity.
"All six wheels have more than enough working lifespan remaining to get the vehicle to all destinations planned for the mission," said Curiosity project manager Jim Erickson at NASA's Jet Propulsion Laboratory.
At present, Curiosity rover resides in the region of Mount Sharp near Gale crater.