A rover (or sometimes planetary rover) is a space exploration vehicle designed to move across
the surface of a planet or other celestial body. Some rovers have been designed to transport
members of a human spaceflight crew; others have been partially or fully autonomous robots.
Rovers usually arrive at the planetary surface on a lander-style spacecraft.
Rovers have several advantages over stationary landers: they examine more territory and they can
be directed to interesting features. If they are solar powered, they can place themselves in
sunny positions to weather winter months. They can also advance the knowledge of how to perform
very remote robotic vehicle control which is necessarily semi-autonomous due to the finite speed
of light.
Their advantages over orbiting spacecraft are that they can make observations to a microscopic
level and can conduct physical experimentation. Disadvantages of rovers compared to orbiters are
the higher chance of failure, due to landing and other risks, and that they are limited to a
small area around a landing site which itself is only approximately anticipated.
Rovers arrive on spacecraft and are used in conditions very distinct from those on the Earth,
which makes some demands on their design. Such as wheel motion and robotic parts.