An example of one of the wheels for #NASA’s #Mars #Science Laboratory #rover, #Curiosity. They have a maximum diameter of 50mm, are 40cm wide, and are made of machined #aluminum.
To save weight, the wheels were machined to a minimum thickness of 0.75mm. There are raised, chevron-shaped #grousers that help provide stiffness and traction that stand 7mm and are at regular, about 65cm, intervals.
To mark the #MarsRover’s progress visually, the wheels were to be marked with a pattern that the camera could see for visual odometry. The designers of #MSL wanted to to use the initials of their organization, #JPL, but #NASA objected to the optics of leaving their initials on another plant, so they just put it in #MorseCode.
Unfortunately, the thinness of the wheels has resulted in their slow degradation as they are torn by sharp rocks and the tears spread. The wheels for #Mars2020 #Perseverance were modified as a result. https://heronfox.pixels.com/featured/curiosity-wheel-2-heron-and-fox.html