28 Origin, Evolution, and Resource Utilization of Planets and Planetesimals

Friday, 24 March 2006
8:00 AM - 12:00 PM

REACTION OF LUNAR SOIL IN A KITCHEN MICROWAVE OVEN

Paper number: 28-11
Program: THEME SESSIONS
Time: 11:00 AM – 11:20 AM

Authors

Abstract

In any return to the Moon, largely because of the high cost of bringing materials from Earth [$25-50,000/lb], it will be necessary for “In-Situ Utilization” [ISRU] of lunar regolith. The unique and unusual properties that have been discovered by research efforts in our Institute here at Tennessee will greatly facilitate such endeavors. “Lunar Soil placed in a kitchen microwave, next to your tea, will melt at 1200 oC, BEFORE the tea-water boils at 100 oC!” (Taylor & Meek, 2005, Jour. Aerosp, Engr.) Lacking an atmosphere and weathering processes such by water and wind, the lunar soil is formed by major space weathering of meteorite and micro-meteorite impacts. Besides the crushing of lunar rock and soil particles, the small (e.g., 50 µm) micro-meteorites can impact with velocities of 30,000 to >100,000 km/hr, sufficient kinetic energy to easily melt the soil. This melt incorporates lithic, mineral, and glass particles into it and freezes, quenching to a glass binder, creating aggregates called agglutinates. In addition, some of this silicate melt volatizes, subsequently being deposited as glass coatings on most of the soil particles. These glass coatings contain abundant nanophase-sized (1-30 nm) metallic Fe grains. It is this nanophase Fe that is largely responsible for the unique magnetic properties of the lunar soil and its extreme reactivity with microwave energy. It should also be noted that our experiments were conducted with real Apollo 17 lunar mare soil.

One can imagine a Lunar Rover pulling a wagon, on which are mounted a row of magnetrons set at specific power and frequency, such that they sinter and partially melt the lunar soil to a depth of 0.5 m; another row of magnetrons at different settings could actually melt the upper layer of the soil down to 5 cm, thereby creating a glass coating to this “Lunar Brick Road.” The products that can be formed by microwave processing of lunar soil are only limited by ones' imagination – e.g., bricks, habitats, radiation shielding, oxygen production, solar-wind volatile collection (for hydrogen).