The big science question for the rover mission 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. That's why the rovers are specially equipped with tools to study a diverse collection of rocks and soils that may hold clues to past water activity on Mars.

The rovers will offer unique contributions in pursuit of the overall Mars science strategy to follow the water. Understanding the history of water on Mars is important to meeting the four science goals of NASA's long-term Mars exploration program:

• Determine whether life ever arose on Mars
• Characterize the climate of Mars
• Characterize the geology of Mars
• Prepare for human exploration

Learn about the rovers' unique contributions to these science goals through the pursuit of seven science objectives:

1. Search for and characterize a variety of rocks and soils that hold clues to past water activity. In particular, samples sought will include those that have minerals deposited by water-related processes such as precipitation, evaporation, sedimentary cementation, or hydrothermal activity.
2. Determine the distribution and composition of minerals, rocks, and soils surrounding the landing sites.
3. Determine what geologic processes have shaped the local terrain and influenced the chemistry. Such processes could include water or wind erosion, sedimentation, hydrothermal mechanisms, volcanism, and cratering.
4. Perform "ground truth" — calibration and validation — of surface observations made by Mars orbiter instruments. This will help determine the accuracy and effectiveness of various instruments that survey Martian geology from orbit.
5. Search for iron-containing minerals, identify and quantify relative amounts of specific mineral types that contain water or were formed in water, such as iron-bearing carbonates.
6. Characterize the mineralogy and textures of rocks and soils and determine the processes that created them.
7. Search for geological clues to the environmental conditions that existed when liquid water was present. Assess whether those environments were conducive to life.

How scientists will rely on the rovers to look for signs of past water

Because scientists cannot go to Mars themselves at this point in time, they will have to rely on robot geologists — the rovers — to look for signs of past water activity on Mars for them.

To do their job, the rovers will carry a number of science instruments that will analyze rocks and soils on the Martian surface and perform other important tasks and studies.

Find out more visit The Planetary Society.

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