ESA Finds Liquid Water on Mars

*Mars’ south pole is covered in layered deposits of ice and sediment. It is below such areas that liquid water has been identified by MARSIS. (Image: ESA/Roscosmos/CaSSIS, CC BY-SA 3.0 IGO)*

Water has been found on Mars! (Yes, again.)

In what’s turned into the biggest space news of the day, today ESA (and that’s pronounced “eesa”, you don’t need to spell it out) announced that the Italian-run radar experiment aboard its Mars Express orbiter has provided the first good evidence of liquid water present beneath the surface of Mars’ south pole. It’s an underground reservoir of water!

The layer of water is shallow—to even have been detected it must be at least several tens of centimeters—sediment-laden and located 1.5 kilometers (about a mile) below the surface, but is fairly widespread within the 200-km area scanned with ground-penetrating radar. The entire “lake” region is at least 20 km across.

ESA’s Mars Express has used radar signals bounced through underground layers of ice to find evidence of a pond of water buried below the south polar cap. Credit: Context map: NASA/Viking; THEMIS background: NASA/JPL-Caltech/Arizona State University; MARSIS data: ESA/NASA/JPL/ASI/Univ. Rome; R. Orosei et al 2018

“This is just one small study area; it is an exciting prospect to think there could be more of these underground pockets of water elsewhere, yet to be discovered,” said Roberto Orosei, principal investigator of the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) experiment and lead author of the paper.

Read the paper on the team’s findings here.

Water is known to exist on Mars in trace amounts that have been spotted sneaking to the surface in fine, briny rivulets on steep slopes, as well as in the form of ice and thin clouds. NASA has rovers on Mars right now looking for evidence of a past environment where water existed in large quantities. But on the surface of Mars today liquid water is a rare and short-lived state; the air is so dry and the atmospheric pressure is so low that water boils off almost immediately. To find evidence of a stable liquid reservoir, even a mile below the surface, is an enormous accomplishment! It carries major implications for not only the possibility of life on Mars but also the habitability and resource potentials of Mars for future human explorers (water can be used not only for drinking but also for growing plants, protection from radiation, and even making rocket fuel!)

“This thrilling discovery is a highlight for planetary science and will contribute to our understanding of the evolution of Mars, the history of water on our neighbour planet and its habitability.”
— Dmitri Titov, ESA’s Mars Express project scientist