The European Space Agency’s Mars Express mission has detected liquid water buried under ice on the red planet.
MARSIS, short for Mars Advanced Radar for Subsurface and Ionosphere Sounding, found three ponds of liquid water. The mission earlier discovered an underground reservoir in 2018.
The largest underground lake measures 20 kilometers by 30 kilometers and is surrounded by several smaller ponds.
Mars Express’ discovery raises the possibility that there is a system of ancient lakes beneath the surface of Mars that may be up to billions of years old, according to the ESA. The underground ponds could be ideal locations to search for Martian life, but it will be very hard to access them, the agency said.
In 2018, NASA’s Mars Reconnaissance Orbiter found sites where thick ice deposits under Mars’ surface are exposed, which makes them accessible to missions on the planet.
Meanwhile, research published in January found that the very small amounts of water vapor left in Mars’ atmosphere is being lost even faster than previously believed, further reducing the chances of finding surface water on the planet.