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Huge ice sheets more than 300 feet deep have been discovered on Mars, making it possible that human astronauts could have access to almost limitless water, scientists said Thursday.

"Astronauts could essentially just go there with a bucket and a shovel and get all the water they need," said one of the report's authors, Shane Byrne of the Lunar and Planetary Laboratory at the University of Arizona.

Snow and ice covering dunes on Mars' Northern hemisphere in a photo taken by NASA's Mars Reconnaissance Orbiter in May 2017. NASA / AFP - Getty Images file

It has been known for some time that some locations on Mars have water ice just below the surface — but until now, there has been no accurate way to know just how much.

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The new data, collected in high-resolution three-dimensional images from two U.S. satellites, reveal at least eight locations where massive shelves of water ice are deposited from just below the Martian surface as far deep as 100 meters, or roughly 330 feet, according to the report, which was published in the journal Science.

Related: NASA details its plans for sending humans to Mars

"The discovery reported today gives us surprising windows where we can see right into these thick underground sheets of ice," Byrne said. "It's like having one of those ant farms where you can see through the glass on the side to learn about what's usually hidden beneath the ground."

The ice shelves contain distinct layers, which could preserve a record of Mars' past climate, the scientists said. Of probably wider public interest, however, is that the ice shelves "might even be a useful source of water for future human exploration of the red planet," they said.

👉Future astronauts: @NASA identified eight icy places on #Mars where you can get all the water you need. BYO bucket & shovel. https://t.co/mqgmOndneu pic.twitter.com/LE272hZunG — Curiosity Rover (@MarsCuriosity) January 11, 2018

The ice probably started as snowfall that compacted into massive fractured layers. They're at relatively easy-to-reach locations with less hostile conditions than at Mars' polar ice caps, according to NASA's Jet Propulsion Laboratory — at latitudes roughly equivalent on Earth to Scotland or the tip of South America.

"Astronauts could essentially just go there with a bucket and a shovel and get all the water they need."

The discovery could add fuel to NASA's efforts to send humans to Mars, one of the objectives President Donald Trump cited last month when he directed the space agency to focus its efforts on returning to the moon.

Related: Debate heats up over the search for life on Mars

Elon Musk, chief executive of SpaceX, has also discussed plans for private manned missions to Mars.

The research, which was funded by NASA, was conducted by the Lunar and Planetary Laboratory along with the U.S. Geological Survey, the nonprofit Planetary Science Institute, Georgia Tech, Johns Hopkins University and the University of Texas.