The presence of liquid water on Mars, past or present, is a key clue in revealing whether Mars ever harbored life. From the tiniest microbe to more complex organisms, life as we know if could not exist without liquid water. The Reconnaissance Orbiter's scientific payload includes instruments to zero in on water-related surface features such as outflow channels from ancient floods, and to study water-related mineral deposits in Mars' rocks and soil. Cameras and spectrometers will carry out these searches, and a sounder will use radar to search for liquid water beneath the martian surface.
[more on Goal 1 for the entire Mars Exploration Program]
In the past, a warmer Mars might have supported a thicker, wetter atmosphere. But now, with its thin cold atmosphere, much of the water on Mars has left the surface and atmosphere. Most of it is probably trapped under the surface, either as ice or possibly in liquid form if any exists near a heat source on the planet, such as a volcanic "hot springs." Mars Reconnaissance Orbiter will search for evidence of present-day ice or liquid water beneath the surface and explore the subsurface structure of the polar caps and nearby terrain in search of evidence of the role water played in Mars' past climate. The mission will also study how dust and water are currently transported in the martian atmosphere. Combining its measurements with those of other missions, the Reconnaissance Orbiter mission will help characterize the daily, seasonal and year-to-year climate variability.
[more on Goal 2 for the entire Mars Exploration Program]
Folded in the layers of Mars surface, like geology's version of tree rings, is a record of Mars' history. With high-resolution instruments, Mars Reconnaissance Orbiter will look in particular for geologic settings that indicate the presence of liquid water on the surface at some point in the planet's history. Examples include ancient lakebeds, salt flats, and mineral deposits characteristics of hot springs. Hundreds of locales will be examined in unprecedented detail to reveal water-related mineralogy and water's role in shaping the terrain.
[more on Goal 3 for the entire Mars Exploration Program]
With eagle-eye vision, the Mars Reconnaissance Orbiter will home in on rocks the size of 3-4 feet. With this capability, mission planners will identify the most promising locales for scientific study and know, too, which are safe and which might be hazardous to future landers carrying humans.