Fate of Water on Mars (IMAGE) California Institute of Technology Caption While it was previously suspected that most of Mars's water was lost to space, a significant portion--between 30 and 90 percent--has been lost to hydration of the crust, according to a new study. Some water was released from the interior via volcanism, but not enough to replenish the planet's once significant supply. Evidence for the water's fate was found in the ratio of deuterium to hydrogen in the planet's atmosphere and rocks. Credit Caltech Usage Restrictions For use in news stories only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.