If we send a crewed spaceship to Mars right now and it lands in a large canyon and starts exploring, they’ll find a mᴀssive deposit of water. The ExoMars Trace Gas Orbiter (TGO) mission discovered “large volumes of water” in the red planet’s Valles Marineris canyon system.

The European Space Agency and the Russian space agency Roscosmos jointly manage TGO. The orbiter is equipped with a device that maps hydrogen in the top layer of Martian soil. Data reveal an unusually high concentration of hydrogen in Candor Chaos, a key section of Valles Marineris, implying that up to 40% of the near-surface material in that location could contain water.

“With TGO we can look down to one meter below this dusty layer and see what’s going on below Mars’ surface — and, crucially, locate water-rich ‘oases’ that couldn’t be detected with previous instruments,” Igor Mitrofanov of the Space Research Insтιтute of the Russian Academy of Sciences said in an ESA statement on Wednesday. Mitrofanov is the lead author of a paper published in the journal Icarus on water discoveries.

Valles Marineris is so huge that NASA refers to it as “the Grand Canyon of Mars.” Except that it’s a lot bigger than the US landmark. The Mars version is 1,860 miles (3,000 kilometers) long and reaches a depth of 5 miles (8 kilometers).

The water in Valles Marineris may be mineralized, but the scientists believe it is more likely to be in the form of ice. This raises the issue of how the water ice is retained in a region of Mars where it would normally evaporate. “This suggests that some special, as-yet-unclear mix of conditions must be present in Valles Marineris to preserve the water — or that it is somehow being replenished,” ESA said.

Scientists have been examining both the past and current presence of water on Mars, looking for what may be hidden lakes (or just frozen clay) and mapping out water ice that could be reached by future human explorers. Locating and utilizing local water resources would be critical to any Mars colonization plans.

“Knowing more about how and where water exists on present-day Mars is essential to understand what happened to Mars’ once-abundant water, and helps our search for habitable environments, possible signs of past life, and organic materials from Mars’ earliest days,” said ExoMars Trace Gas Orbiter project scientist Colin Wilson.

According to NASA, the Valles Marineris canyon is the biggest known canyon in the solar system, stretching from New York to California if it were on Earth. If space tourism ever makes it to Mars, the canyon system would be a sight to behold. With an abundance of water in the mix, we may be looking at Mars as humanity’s future home away from home.