20-year-old rover data reveals Mars had far more water than expected

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Rover data from more than 20 years ago has revealed clues to the existence of liquid water on ancient Mars. The NASA Spirit Rover carried a specialized instrument called a Mössbauer Spectrometer that performed mineralogical analyses of soil, rock, and dust on the surface of the Red Planet at Gusev Crater. Individual measurements didn't always indicate definitive proof of water, but when scientist Paolo de Souza of Edith Cowan University in Australia examined years' worth of measurements together, a definite pattern began to show up in the existence of minerals that could only exist in the presence of water. His analysis shows that Mars used to sport a lot more water than scientists expected and that the data showing its existence was in the data all along.