While the rovers cannot search for existing life forms on Mars, they do have the ability to search for presumably life-sustaining qualities of the Red Planet, namely the presence of water. Opportunity came across several small spheres (nicknamed “blueberries”) embedded in the rock layers near the surface of Mars. After further tests, it was determined that the blueberries were predominantly made up of the mineral hematite, which generally forms near water here on Earth. Spirit made a similar discovery when it found goethite, which forms on Earth only in the presence of water. Several other discoveries were made which helped confirm that water did indeed exist on Mars at one time. While there is no way to prove that water is the only thing needed to provide a favorable living environment on Mars, its presence on the Red Planet is an encouraging sign that microbial life may have existed on the planet at one point.
The climate of Mars is also directly linked to the possibility of life existing on the planet. Liquid water cannot be found on the surface because the temperature and atmospheric pressure are too low. Part of the mission of the rovers is to examine the current climate, allowing scientists on Earth to potentially determine past and future climate patterns on the planet. Atmospheric conditions affect the amount of sunlight and heat that reaches the surface of Mars, thus affecting the living conditions for Martian organisms and/or humans in the future.
As mentioned previously, the rovers were equipped with geological tools to collect and analyze rock and mineral samples from atop and beneath the surface. NASA is particularly interested in minerals containing iron, since it oxidizes when in contact with liquid water. One question being asked was about the red colored Martian soil: is it red due to iron oxidation in a wet environment, or is it because of other rocks reacting to the Martian atmosphere? Mars’ topography is also an area of interest because parts of it clearly display different layers of sediment starting from millions of years ago. Curiosity is currently looking into the different layers to determine how the surface of Mars has evolved over time, including the elusive period when Mars transitioned from a wetter environment to the dry one it is now.
As the rovers traverse Mars, they are determining environmental, chemical, and mineral characteristics of the planet’s soil, dust, and atmosphere, likely finding potential dangers they may pose to any humans who may go to Mars. They will also identify soils and rocks as potential resources for human missions. Additionally, they will serve as test cases for future rover and human missions.
The three Mars rovers – Spirit, Opportunity, and Curiosity – have provided groundbreaking discoveries, mainly the detection of specific spots on the Martian surface that could have been habitable due to the presence of water in. Opportunity and Curiosity continue to perform work to help find out the history and future of Mars.