Lunar Dust Rims - Glassy rims produced by vapor/sputter deposition - tell a history of cosmic ray bombardment and Solar Wind, explaining optical maturity... "also contain approximately 10 nm Fe nanoparticles (nanophase iron)." [Sarah Noble, NASA/Marshall Space Flight Center]
Wyle Labs., Inc.
NASA Johnson Space Center
University of Tennessee - Knoxville
Lunar regolith is highly activated by grinding. Reactivity is dependent upon sample maturity (and locale). Maturity is measured by the amount of nanophase iron (np-Fe) in a sample, relative to the total iron oxide (FeO). Lunar regolith activity is a direct function of the amount of np-Fe present. Reactive samples are "deactivated" quickly after exposure to humid air on Earth.
- NASA Human Research Program Investigators' Workshop