The accumulation of a valuable resource at low latitudes opens up prospects for potential expeditions.
The Trace Gas Orbiter (TGO), part of the ExoMars programme of the European Space Agency and Roscosmos, has discovered vast water reserves in the Mariner valleys, the largest known canyon in the solar system.
The discovery was made by the FREND epithermal neutron detector, which analyses the hydrogen content of the Martian soil layer to a depth of one metre.
Astronomers have found water on Mars before, but mostly in cold polar regions and in the form of ice. The canyon system, on the other hand, extends for more than 4,000 kilometres along the planet's equator.
Lead researcher Igor Mitrofanov said water molecules account for about 40 percent of the near-surface rocks in Candor Chaos, and that deeper underground there could be rich "oases".
Scientists have yet to determine the exact composition and form of the water, but the fact that the valuable resource accumulates at low latitudes opens up new prospects for research and expeditions.
The TGO probe has been in orbit since 2016, and the European rover Rosalind Franklin and the Russian Kazachok landing platform will join the mission in 2022 to find out if life ever existed on Mars.
