After investigating the upper atmosphere of the Red Planet for a full Martian year, MAVEN has determined that escaping water does not always go gently into space.
Sophisticated measurements made by a suite of instruments on the MAVEN spacecraft revealed the ups and downs of hydrogen escape—and therefore water loss. The escape rate peaked when Mars was at its closest point to the sun and dropped off when the planet was farthest from the sun. The rate of loss varied dramatically overall, with 10 times more hydrogen escaping at the maximum.
“MAVEN is giving us unprecedented detail about hydrogen escape from the upper atmosphere of Mars, and this is crucial for helping us figure out the total amount of water lost over billions of years,” said Ali Rahmati, a MAVEN team member at the University of California at Berkeley who analyzed data from two of the spacecraft’s instruments. [More at link]