The Lunar Dust Problem: From Liability to Asset

In-Situ Resource Utilization (ISRU) of lunar materials for the establishment of an extra-terrestrial human base or settlement will involve guarding against, as well as utilizing, the ever-present, clinging, penetrating, abrasive, resource-rich, fine-grained lunar dust. The properties of the fine portion of the lunar soil (<50 μm), its dust, must be adequately addressed before any sustained presence on the Moon can be fully realized; these include: 1) abrasiveness, with regards to friction-bearing surfaces; 2) pervasive nature as coatings, on seals, gaskets, optical lens, windows, etc., 3) gravitational settling on all thermal and optical surfaces, such as solar cells; and 4) physiological effects on the tissue in human lungs. The chemical and physical properties of the fine fraction of lunar soil is at the root of the unusual properties of the dust that contribute to its deleterious effects – its “liability". Recent discoveries of the unique magnetic properties of lunar mare and highland soils by the senior author’s Tennessee group have led to suggested solutions to the liability of the lunar dust. The soil fragments and dust grains contain myriads of adhering nano-sized (3-30 nm) Fe particles, iron in its elemental form, concentrated especially in the fine, dusty fraction. The presence of this ferromagnetic Fe on and in almost every grain of the fine dust-sized particles imparts an unusually high magnetic susceptibility to the particles, such that they are easily captures by a magnet. Furthermore, the presence of these nanophase Fe grains imparts an unusual property to the soil for microwave energy. The microwaves couple strongly with the Fe to such a degree that a sample of Apollo soil placed in an ordinary 2.45 MHz kitchen microwave will literally begin to melt before your tea-water boils. Further considerations of the properties of the fine soil are the basis for the microwave sintering/melting, hot-pressing, and extrusion of the soil to form various construction materials, in order to realize some of the "assets" of the soil