A reservoir of water within the crust of Mars has been discovered by NASA’s “Insight” mission. Researchers believe  the amount of water buried 7-12 miles deep in the Martian crust could cover the planet’s surface to a depth of one mile.

In November of 2018, the Insight Lander reached Mars, carrying a seismometer and heat probe to study the atmosphere, crust, mantle and core of the planet. The seismometer recorded the planet’s vibrations for four years, tracking 1,319 marsquakes. After analyzing data from the seismometer, scientists were able to detect seismic waves of liquid water passing through the rocks.

Astronauts would have a hard time accessing this water since it is so far beneath the surface. For reference, the deepest humans have dug into Earth is the Kola Superdeep Borehole in Russia, which took 20 years to dig, in hopes of reaching the Earth’s mantle. However, they had to stop at a depth of 7.6 miles because the temperature reached 356 degrees Fahrenheit.

It was previously estimated that water was last present on Mars 3 billion years ago; the  loss of a magnetic field and a dense atmosphere resulted in the disappearance of water, with the exception of frozen water in the Martian poles. 

This discovery indicates that not all the water was lost in space, but instead filtered down through the crust.