To explore planet Mars NASA has a special mission, called NASA Mars Rover mission. The mission sends robotic vehicles, called rovers, to study Mars up close and personal.  So far NASA has sent their five robotic vehicles : Sojourner, Spirit, Opportunity, Curiosity and Perseverance.

With rover there are several advantages like examining more territory, ability to direct the vehicle to interesting places and develop the knowledge of remote robotic control technology. Each rover mission has specific tasks to complete.

According to Planetary Society website the Mars Exploration Rovers mission set out to achieve 7 primary science objectives, which both Spirit and Opportunity achieved by the end of April 2004, within their 90-day primary missions:

• Searching for and studying many different types of rocks and soils that might hold clues to past water activity.
• Producing maps showing the locations of different kinds of rocks and soils around the landing sites.
• Determining what forces have shaped the landscape and how they created the landscape.
• Examining places on the ground observed from orbiting spacecraft or, in other words, “ground truthing.”
• Studying iron-containing minerals and uncovering minerals that contain water or must have formed in water.
• Identifying the minerals and textures in rocks and soils and determining how they were made.
• Searching for clues to what the environment was like when liquid water was present, whether the water was present for a long time or not, and whether the environment could have supported life.