Make that 7 km
At the equator, but only 3.5 km at the poles. Way too deep to dig.
That's the average, though. There should be places as shallow as half or 1/4 the average.
Space/Science » in reply to water for colonization
At the equator, but only 3.5 km at the poles. Way too deep to dig.
That's the average, though. There should be places as shallow as half or 1/4 the average.