LRO data shows lunar ice deposits are widespread

LRO data shows lunar ice deposits are widespread
by Clarence Oxford
Los Angeles CA (SPX) Oct 04, 2024

A new analysis from NASA's Lunar Reconnaissance Orbiter (LRO) mission reveals that lunar ice deposits are more widespread than previously believed. These ice reserves could serve as critical resources for future lunar missions, providing water for radiation protection, human consumption, and for producing fuel and breathable air.

Earlier studies had detected ice in the permanently shadowed regions (PSRs) near the lunar South Pole, including craters like Cabeus, Haworth, Shoemaker, and Faustini. However, the latest research shows that ice extends beyond these areas. "We find that there is widespread evidence of water ice within PSRs outside the South Pole, towards at least 77 degrees south latitude," said Dr. Timothy P. McClanahan of NASA's Goddard Space Flight Center, the lead author of the study published in the 'Planetary Science Journal'.

The study provides new maps and insights into surface conditions, helping mission planners locate and prioritize areas for exploration. "Our model and analysis show that greatest ice concentrations are expected to occur near the PSRs' coldest locations below 75 Kelvin and near the base of the PSRs' poleward-facing slopes," McClanahan added.

However, accurately determining the volume of ice deposits or whether they are buried under regolith remains challenging. "We expect that for each surface 1.2 square yards residing over these deposits, there should be at least about five more quarts of ice within the top 3.3 feet of the surface," McClanahan said. The study also identifies areas where smaller or lower concentrations of ice might exist, mostly in warmer, periodically sunlit regions.

Ice may accumulate in lunar regolith through comet impacts, outgassing from the Moon's interior, or chemical reactions involving solar wind hydrogen and regolith oxygen. PSRs, which are located in topographic depressions near the poles, remain in perpetual darkness and extreme cold due to the low angle of the Sun. This environment helps preserve ice molecules that might accumulate over billions of years. Ice on surfaces exposed to sunlight likely evaporates quickly, preventing the formation of deposits.

The research team used LRO's Lunar Exploration Neutron Detector (LEND) to detect signs of ice by measuring moderate-energy neutrons. Specifically, they utilized the Collimated Sensor for Epithermal Neutrons (CSETN), which covers an 18.6-mile-wide area. By measuring reductions in neutron energy, which correspond to the presence of hydrogen, the team could infer the existence of ice in the PSRs.

"We hypothesized that if all PSRs have the same hydrogen concentration, then CSETN should proportionally detect their hydrogen concentrations as a function of their areas," McClanahan explained.

The study analyzed neutron data from 502 PSRs, with areas ranging from 1.5 square miles to 417 square miles. While the correlation between hydrogen concentration and PSR size was weaker for smaller PSRs, it increased significantly in larger PSRs.