Water on the moon

Author: John Monczunski

They say you can’t squeeze water from a stone, but some rocks securely locked away in a safe in Clive Neal’s office prove otherwise.

For more than 20 years, the Notre Dame professor of civil engineering and geological sciences has been working on lunar samples gathered by the six Apollo missions that landed on the moon from 1969 to 1972.

Neal, who is chair of NASA’s Lunar Exploration Analysis Group, has been especially interested in rocks that contain ilmenite. The mineral, composed of iron and titanium oxide, soaks up protons (hydrogen nuclei) when exposed to the solar wind, the stream of charged particles that are ejected from the sun.

That property may be especially useful for any future manned lunar base. Because of it, the rocks yield water and oxygen when heated in a vacuum. The ilmenite undergoes a reduction reaction, Neal explains. Oxygen atoms from the mineral combine with hydrogen from the solar wind to form water; the excess oxygen atoms, meanwhile, are released as free oxygen.

Currently, the ND lunar geologist and his colleagues are examining the crystalline structure of lunar ilmenite, attempting to determine exactly how exposure to the solar wind alters the alignment of the atoms.

An expert on volcanism, Neal also has been analyzing lunar “melt rocks,” either from lava flows or those produced from the heat of meteorite impact.

Neal’s lab has been studying their chemical makeup and determining their age. “It’s been hypothesized that about 3.9 billion years ago the moon experienced a heavy bombardment of impactors,” he explains. “So if it turns out that most of our samples from impacts are around 3.9 billion years old, that supports this late cataclysm hypothesis.”

John Monczunski is an associate editor of Notre Dame Magazine.