Rovers are what scientists call any vehicle which travels on the surface of a moon or planet that isn't Earth. So far Rovers have landed on the Moon, and Mars. Some rovers like the Moon Buggy were just cars that were driven by astronauts so that they could travel a long way from their space ships. Other rovers such as Spirit, Discovery and every other rover which has landed on Mars are very complicated remote controlled cars with cameras, robot arms, and many other sensors. Scientists control these remote controlled rovers from Earth and use them to study the surface of Mars. Remote controlled rovers are used instead of astronauts because they don't need food, water, or air, and its alright to leave them on Mars because they don't get homesick like people.
