Using secondary ion mass spectrometry (SIMS) which can detect elements in the parts per million range, scientists at the Carnegie Institution’s Geophysical Laboratory found the minimum water content ranged from 64 parts per billion to 5 parts per million—at least two orders of magnitude greater than previous results
The moon is 7.349 X 10^19 tons. So the 5 parts per million all the way through would mean 3.6* 10^13 tons of water and the lower estimate of 64 parts per billion would mean about 4 * 10^11 tons of water.
But the water ratio may not be constant all the way through and the estimate provided is the minimum water content. The previous estimates of 600 million tons of water ice on the moon would be water that is closer to the surface and more usable for colonies or moon missions.
The SIMS technique measures hydroxyl by bombarding the grains of a type of phosphorous, water-bearing mineral called apatite with high-energy particles and counting the ions that are ejected. Based on the SIMS measurements, the scientists authors place the lower limit for the total lunar water at 100 times greater than previous estimates, and speculate that water may be “ubiquitous” in the moon’s interior. The study could alter current theories about lunar magmatism (how igneous rock formed from magma), and how the moon formed and evolved.
Mars Global Ocean 3.5 Billion Years Ago
The latest Mars study from the University of Colorado combined the analysis of water-related features including scores of delta deposits and thousands of river valleys with a look at the possibility of a global hydrosphere on early Mars, found that a vast ocean likely covered one-third of the surface of Mars some 3.5 billion years ago. The volume of the ancient Mars ocean would have been about 10 times less than the current volume of Earth’s oceans. Mars is about half the size of the Earth.