Spirit:
Spirit is the first of the twin Mars Exploration Rovers to reach Mars in January 2004. Its robotic twin -
Opportunity - landed on the opposite side of the planet.
The big science question for both rovers is how past water activity on Mars has influenced the Red Planet's environment over time. While there is no liquid water on the surface of Mars today, the record of past water activity on Mars can be found in the rocks, minerals, and geologic landforms, particularly in those that can only form in the presence of water.
Read more about Spirit
Visit the Spirit Website
