There are different kinds of vehicles. it's actually dust because Mars is known to have Strong winds that tends to lift a lot of dust off the ground.
- Note that tires on most vehicle are tread like in nature and so is that of Mars Rover vehicle. So it does pick up dust as the vehicles is rubbing against the surface, this dust is then trapped in this treads.
What is the atmosphere of Mars?
The atoms on Mars consist of Protons and Electrons. The atmosphere of Mars is known to be primarily composed of carbon dioxide, molecular nitrogen and argon. It has been found to have some little amount of water vapor, oxygen, carbon monoxide, hydrogen and noble gases.
A high percentage of water on Mars exists in form of ice, though it is said to exists in small quantities in vapor form in the atmosphere.
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