# Transcript

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Tracking water loss on Mars

Liquid water once flowed across the martian surface, but where did it go?

Some water is in ice caps and underground, but water loss still occurs today

The ESA-Roscosmos ExoMars Trace Gas Orbiter is providing data on Mars’ climate evolution and its habitability potential

ExoMars is following the vertical path of water through the atmosphere and its changing isotopic composition

As water moves to colder regions it condenses and its isotopic composition changes

Independent of reservoir, and over time, the ratio of D to H atoms increases

Today, the D/H ratio is about six times higher on Mars than Earth indicating great water loss

Water loss is accelerated during dust storms when the atmosphere is warmer

Southern summer drives water loss as the pole is heated up

ExoMars will continue to provide new insights into the history of water on Mars