r Geotechnical Institute, P.O. Box 5056, Lakeland, FL 33807

And

Masami Nakagawa
4

Division of Engineering, Colorado School of Mines, Golden, CO 80401

ABSTRACT

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 authors
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
0
particles, iron in its elemental form, concentrated especially
in the fine, dusty fraction. The presence of this ferromagnetic Fe
0
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
0
grains imparts an unusual property to the soil for
microwave energy. The microwaves couple strongly with the Fe
0
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

I. Introduction

The economic and societal rewards from exporting resource commodities from the Moon to LEO and to Earth,
and potentially to Mars, as well as for use at a lunar base or settlement, would appear to be very great if not
limitless. In fact, resources from the Moon can have a direct bearing on potentially reducing the cost and extending
the longevity of the International Space Station (ISS) or future such stations. The ISS consumption of hydrogen,
oxygen, and water can be satisfied by production of these commodities from lunar soil. For example, the production
of liquid lunar oxygen (LLOX), liquid lunar hydrogen (LLH), and water involve relatively uncomplicated, well-
characterized and researched processes on the Moon
1-5
. The beaming of electrical power from lunar solar cells to
LEO and Earth has been examined in detail by Dave Criswell
6
. The potential of a D-
3
He energy reactor being
created and capable of using lunar
3
He becomes closer to reality each year, largely through the research of G.L.
Kulcinski's team
7-10
at the Fusion Technology Institute (University of Wisconsin-Madison. Even placing astronomy
instrumentation on the Moon and the establishment of human habitats are areas of open discussion and planning in
many NASA and private circles. But, what do all of these apparent dissimilar activities have in common? Lunar
Dust.
1st Space Exploration Conference: Continuing the Voyage of Discovery
30 January - 1 February 2005, Orlando, Florida
AIAA 2005-2510
Copyright © 2005 by Lawrence A. Taylor. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.
American Institute of Aeronautics and Astronautics

2
All these activities on the lunar surface involve utilizing or guarding against the ever-present, clinging, abrasive,
resource-rich, fine-grained lunar dust. In fact, the deleterious effects of the lunar dust [defn: fine portion of the lunar
soil, herein defined as <50
µm] became apparent with the first lunar excursion (EVA) by Neil Armstrong and Buzz
Aldrin during the Apollo 11 Mission and the return of the first lunar samples. The various rocks and soil samples
were placed in rock boxes. These were sealed at 10
-12
torr on the Moon, only to be found to be at 1 atmosphere
when opened in the Lunar Receiving Lab (LRL) at Johnson Space Center in Houston. [Author L.A. Taylor was in
the LRL at that time.] The presence of the clinging lunar dust had made the indium, knife-edge seals fail. This
dust was so pervasive that no lunar rock boxes from any of the 6 Apollo missions to the Moon ever maintained their
lunar vacuum -- they all leaked. Additionally, pressurization of the lunar module used more oxygen after the initial
opening of the hatch in order to offset the leaks from the poor seal on closing. The astronauts suits had
considerable dust embedded in their outer fabric, after each EVA, which could not be brushed off. Bearings
between the suit gloves and arms and the helmet and neck were visibly scratched around their circumference (no
significant increase in leak rate was noted, however.). The inside of the Lunar Module (LM) was temporarily full
of dust, including the atmosphere that the astronauts breathed, as related by Apollo 17 astronaut Harrison H.
Schmitt, a co-author of this paper. This cabin dust settled quickly, but was noted again when the LM became
weightless after ascent from the Moon before being filtered out by lithium hydroxide (LiOH), carbon dioxide filters.
Brushes were used before reentering the LM, but with little effect other than to fatigue the astronauts arms and
fingers. Wet wipes were used in the Lunar Module with good effect to clean bearings and visors, and an inefficient
vacuum cleaner was employed in the Command Module. The cameras that the astronauts used suffered from lunar
dust on the lens, a situation that was tolerated rather than solved. Another example of the deleterious effects of lunar
dust involved the friction caused by the extremely abrasive nature of the lunar soil. This dust was responsible for
wearing through portions of the outside fabric layers of gloves and lower legs of the astronauts suits. This extreme
abrasiveness of lunar dust must be addressed by engineering design studies before there can be adequate cost
analysis for in-situ resource utilization or other activities on the Moon. Picture the large arrays of solar cells and
reflective thermal control surfaces covered with fine layers of dust, reducing their efficiency. The presence of dust
on the delicate optical instrumentation of the astronomers and astrophysicists also will need to be countered,
although no degradation of laser reflector corner cubes after 35-40 years has been reported. This dust makes up 40-
50% of the lunar regolith (soil). Also, recall that the movement and adherence of all particles on the Moon is greatly
enhanced by the 1/6-G environment, the hard vacuum, and the extreme dryness that leads to static electricity
between soil particles. Some characteristics of the dust lead to significant losses of solar-wind volatile resources
merely due to agitation during sample handling
11
.
Lunar dust properties that must be addressed before any commercial presence on the Moon can be fully
evaluated are: 1) abrasiveness and penetration, with regards to friction-bearing surfaces; 2) pervasive nature as
coatings, on seals, gaskets, optical lens, windows, et cetera; 3) settling on all thermal and optical surfaces, such as
solar cells; and 4) physiological effects on humans, especially with respect to the lungs, lymph system, and heart.
The chemical and physical properties of the fine fraction of the lunar soil the dust is at the root of the unusual
properties of the dust that contributes to its deleterious effects its liability. Armed with a sufficiently detailed
knowledge of these fine particles, it should be possible to address and remedy the above-mentioned dust problems.
Below, the unique properties of the lunar soil that we already know are addressed. Recent findings have led to the
suggested solutions to the liability of the lunar dust. Further considerations of the properties of fine soil form the
basis for creating a process of hot-pressing and microwave sintering/melting to form various construction materials
on the Moon, in order to realize some of the assets of the soil. Microwave heating in-situ or nearly in-situ also
may mitigate the problem of volatile losses due to agitation. In fact, the properties of fine portion of the lunar soil,
the dust, and many of the principles discussed in this paper are the basis for patents (pending) by senior-author L.A.
Taylor and the University of Tennessee for remediation and ISRU of the Lunar Dust Problem. In this paper, we
will outline our proposed approach to this dust endeavor, based upon previous scientific/engineering knowledge
derived from extensive studies of Apollo regolith and its finer fraction (<1 cm), the soil.
II. Science of Lunar Soil

Lunar soil is dusty; typically, over 95% is finer than 1 millimeter; about fifty percent is finer than 60
µm (the
thickness of a human hair); and 10-20% is finer than 20 microns. The lunar soil particle-size distribution is very
broad: 'well-graded' in geotechnical engineering terms, or very poorly sorted in geological terms. In addition,
because of t