The deposit was found beneath Utopia Planitia, the Martian plain where NASA”s Viking 2 robotic lander set down in 1976.
NASA”s Mars Reconnaissance Orbiter”s ground-penetrating radar found the huge slab of ice which is up to 560 feet thick.
Cassie Stuurman, also of University of Texas, added: “This deposit probably formed as snowfall accumulating into an ice sheet mixed with dust during a period in Mars history when the planet”s axis was more tilted than it is today.”
The thin Mars rock means the first human Mars explorers can easily drill into the ice.
Could the ice mean there is life already on Mars?
“Where water ice has been around for a long time, we just don”t know whether there could have been enough liquid water at some point for supporting microbial life,” Holt added.
There is also evidence of ancient river channels on Mars where it is thought that subsurface ice melted and flowed.
Alien hunters have been searching for life on Mars for decades.
This week they discovered what appeared to be a reptile scrambling over the red dirt.