The MRO or Mars Reconnaissance Orbiter was sent on August of 2005 to further explore the planet Mars in more detail. Scientists hope to gather detailed information with this latest and most advanced orbiter to understand whether Mars once had life thriving on it in the past. In the past, photos from previous orbiters could not give scientists the high resolution photos necessary to study Mars in its entirety. Even Spirit and Opportunity, as advanced as they are, are limited in contrast to MRO.
Scientists take a "follow the water" attitude when searching for life and Mars. Mars, being the planet most like Earth, having water ice on its surface and being closer to the sun than most other water and ice planets in the solar system is the most logical place to look for water.
One of the most interesting things about water is how it affects rock. Water, especially hot water, can change not just the shape and formation of rock but it can change the color of rock. The MRO's high resolution cameras will be able to pin point details about objects as tiny as pebbles from its position in space. This will give scientists a close look at where and how color variations in Mars rock is distributed over the planet's surface and sub-surface. This might give them some idea of what water activity was like in its past.
Scientists feel that by studying the climate, rock, rock formation and temperatures on Mars they will better understand its weather patterns which are closely related to water activity now and in the past. Much of the reason for Mars's weather patterns is because Mars has no large moon like Earth does to stabilize it on its axis. It swings from axis to axis and because of this it has wild weather patterns. With new instruments like MRO scientists can find even more clues to its climate.
As far as "follow the water" goes, what scientists are looking at is how water vapor moves in the atmosphere, the morphology of the surface, composition and shape of the surface and probing beneath the surface of the planet to see how water moved and shaped the planet in the past. Some of the instruments that make up the MRO are CRISM and SHARAD. SHARAD (Shallow Subsurface Radar) looks for ice underneath the surface of Mars, underground ice reserves and possibly even liquid water. CRISM (Compact Reconnaissance Imaging Spectrometers for Mars) is an imaging spectrometer that will study composition of the minerals on the surface. MRO can take planet wide scans and use these planet wide maps to study atmospheric conditions and climate change from year to year and month to month and weather changes from day to day. All of these things are part of the "follow the water" mindset that scientists studying Mars exploration have adopted.
It is an excellent decision as it may determine if and how we can later colonize Mars. CRISM can also analyze the light that reflects and interacts with Martian rock. Each different mineral on Earth affected by water has a different color. CRISM can detect changes in color in rock and can predict where water might have been or still might be present on Mars. In the future a spectrometer probe on the ground can confirm it. All of this work with MRO aids scientists in their search for water, and more importantly life and life sustainability.
So what does this mean for the rest of us? For future human travel to Mars examining the planet helps us learn how to deal with sweeping dust storms or other weather issues. These storms can be planet wide and forbidding - they can blot out the sun and affect solar powered vehicles and buildings. The sand can cause serious problems with the functioning of equipment. These instruments together can help scientists determine where on Mars is the best and safest place to land robots and probes and later the best places for humans to land on and begin terra-forming.