Running those numbers, Clarke and his co-authors estimate that of the mile-deep layer of water that may once have been the average across Mars, tens to hundreds of meters may have escaped to space. That still leaves the majority of the lost water trapped underground or locked up in polar ice caps, but plenty just drifted off too.

NASA ‘s Hubble Space Telescope and MAVEN mission are working to solve this mystery. Mars’s water can freeze into the ground or break into atoms, which then escape into space. We need to understand how these atoms leave the planet to determine how much water Mars had and what happened to it.

Cornell researchers explain Mars' bright radar reflections with ice layer interference, challenging the idea of liquid water beneath the pole. Cornell University researchers have provided a simple and

Researchers believe NASA’s Hubble Space Telescope and the Mars Atmosphere and Volatile Evolution (MAVEN) mission have provided insights into how the Red Planet lost much of its water supply.

Scientists explore Mars water loss, tracing hydrogen and deuterium escape with advanced space telescopes like MAVEN and Hubble.