The information that has been studied has come from the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) instrument on the American space agency's Mars Reconnaissance Orbiter spacecraft.
The scientists also think that Mars had widespread water for a very long time.
The data shows that Mars' highlands, which cover about half of the Red Planet, contain clay minerals and these substances can only form if water is present.
Apparently volcanic lavas later on buried the clay-rich areas in drier periods of Mars’ history, but impact craters then went on to expose them again all over the planet in thousands of places.
The clay minerals, which are known as phyllosilicates, hold a record of water interacting with rocks, and in the wake of these findings, the European and US space agencies are planning to use some of the phyllosilicate-rich parts of Mars as possible landing sites for future rover missions.
