NASA’s Curiosity rover has been roaming the red planet’s seemingly lifeless surface for almost four-and-a-half years to date, moving slowly and efficiently. Throughout this time, it has rolled almost a grand total of 9.9 miles. It's moving along on a rough rocky and sandy surface, so it isn’t surprising to learn that the rover’s is subjected to wear and tear, just like any other vehicle used here on Earth.
NASA’s latest announcement reveals that the wheels are breaking down from all the beatings they receive; images shared by a recent rover checkup earlier this year, which was performed with the same camera that typically allows Curiosity to take selfies, reveal that the unique tread on them are beginning to come loose and fall off.
Image Credit: NASA/JPL-Caltech/MSSS
NASA is so far satisfied with how long the rover’s aluminum wheels have lasted, and suggests that they still have at least 60% of their operating life left before they are no longer effective and need to be replaced.
“All six wheels have more than enough working lifespan remaining to get the vehicle to all destinations planned for the mission,” said Jim Erickson, the Curiosity Project Manager at NASA's Jet Propulsion Laboratory in Pasadena, California. “While not unexpected, this damage is the first sign that the left middle wheel is nearing a wheel-wear milestone.”
For what it’s worth, NASA’s Curiosity rover is approximately as large as a full-size car, and each aluminum wheel is about 20 inches in diameter by 16 inches wide. The treads, which NASA says are known as “grousers,” aren’t like ordinary car tire treads, rather they’re zig-zaggy and allow the wheel to bite into the loose surface more easily. There are 19 of these per wheel.
The rover isn’t light, so when it crawls over rocks here and there, the sharp objects can easily wreak havoc on the aluminum wheels. Unlike other metals, aluminum is more prone to bending and warping because it’s a softer metal, but it’s also lighter and more corrosion-resistant, which made it the optimal choice for the Curiosity mission. To add to their rigidity, they were milled from solid blocksof aluminum in a machining facility.
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Because everything is going according to plan for Curiosity, including its predicted wear and tear, it’s assumed the rover will continue carrying out its scientific duties without any issues. Curiosity will continue to sweep the red planet autonomously for at least 3.7 miles more so we can continue to learn more about it.
Soon, the Mars 2020 rover mission will render Curiosity obsolete, so let's all just hope that Curiosity can hang in there long enough for the new rover to arrive and resume where Curiosity left off.