NASA Technical Reports Server (NTRS) 20060024525: Standard Lunar Regolith Simulants for Space Resource Utilization Technologies Development: Effects of Materials Choices

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NASA Marshall Space Flight Center
STANDARD LUNAR REGOLITH SIMULANTS FOR SPACE RESOURCE UTILIZATION
TECHNOLOGIES DEVELOPMENT: EFFECTS OF MATERLALS CHOICES.
Laurent Sibille' and Paul K. Carpenter'
1B AE Systems Analytical and Ordnance Solutions, NASA Marshall Space Flight Center XD42, Huntsville, AL
358 12; LaurentSibille- l@,nasa.gov and Paul.K.Carpenter@,nas,nasa.gov
Introduction: As NASA turns its exploration am- lunar regolith below 20 microns can represent up to
bitions towards the Moon once again, the research and 30% by mass of the total regolith [3]. Lunar dust simu-
development of new technologies for lunar operations lants are critical for studies on human toxicology and
mechanical abrasion and fouling of systems including
face the challenge of meeting the milestones of a fast-
space resource utilization technologies.
pace schedule, reminiscent of the 1960's Apollo pro-
Importance of using SLRS in space resource
gram. While the lunar samples returned by the Apollo
utilization: Lunar regolith simulants have a grain size
and Luna missions have revealed much about the
distribution and distinct modal mineralogy at each size
Moon, these priceless materials exist in too scarce
fiaction that must be retained in order to match the
quantities to be used for technology development and target lunar regolith. As the sample size is reduced, at
testing. The need for mineral materials chosen to simu- some point it is no longer representative. The devia-
late the characteristics of lunar regoliths is a pressing tion in properties is typically monitored by chemical
issue that is being addressed today through the collabo- analysis using major, minor, and trace element analyti-
ration of scientists, engineers and NASA program cal data of progressively smaller sample sizes, and
managers. The issue of reproducing the properties of comparing these data with replicate afialyses performed
on bulk material. This problem is illustrated in the
lunar regolith for research and technology develop-
case of lunar simulant MLS-1 [4], where a -10% varia-
ment purposes was addressed by the recently held
tion in Si02 is observed, compared to a 160% varia-
2005 Workshop on Lunar Regolith Simulant Materials
tion for Cr. This is a chemical contrast effect, illustrat-
at Marshall Space Flight Center. The recommendation
ing small differences in the major element Si for sili-
of the workshop of establishing standard simulant ma-
cates, but large differences for the trace element Cr.
terials to be used in lunar technology development and Such variations play an important role in the behavior
testing will be discussed here with an emphasis on of the simulant when chemically processed for elemen-
space resource utilization. The variety of techniques tal extraction or transformation. The standardization of
and the complexity of functional interfaces make these the modal composition of these simulants is also criti-
simulant choices critical in space resource utilization. cal to obtain murate simulation of phase diagrams and
Standard Lunar Regolith Simulants (SLRS): A related properties such as viscosity at given tempera-
lunar simulant is manufactured fkom terrestrial compo- tures and pressures.
nents for the purpose of simulating one or more physi- Similarly, geotechnical properties may be dominated
cal and chemical properties of the lunar regolith. A by a large dXmnce iq mineral hardness, and rogue
root simulant represents an end-member in terms of grains would stand out in tests using too small a quan-
simulant properties, and a derivative simulant is tity of material. The variability of simulant material
formed &om a root by modification or addition of mate- thus is an inherent property but must be taken into
rial [ 11. The degree of duplication of soil characteristics account for both quality control and for simulant use
in the simulant is the simulant Jidelity. The 2005 by the scientific community.
Workshop recommended production of two root simu- References: [l] Sibille L. et al. (2005) Lunar
lants corresponding to a low-Ti mare basalt and a Regolith Simulant Materials: Recommendations for
high-Ca highland anorthosite. These roots represent Standardization, Production and Usage, NASA
compositional end-members of mare and highland ma- Technical Publication. [2] Taylor L. et al. (2004)
terials, and can in principle be physically mixed to Space Resources Roundtable VI, 46. [3] D.S. McKay
target the range of soil compositions in the Apollo et al. (1991) Ch. 7 in Lunar Sourcebook, Eds. G.
inventory. Specific lunar regolith properties can be Heiken, D. Vaniman, B.M. French; and W.D. Carrier
addressed by addition of ilmenite, glassy agglutinates, et al. (1991) Ch. 9 in Lunar Sourcebook, Eds. G.
nanophase iron, and other materials [2]. The fidelity of Heiken, D. Vaniman, B.M. French; [4] Weiblen P.W.,
root simulants is thus increased by addition to form Murawa M.J., and Reid K.J. (1990) Engineering, Con-
derivative simulants. While the larger size fraction of struction and Operations in Space 11, ASCE, 428-435.
the lunar regolith has been reproduced in several simu-
lants in the past, little attention has been paid to the
'fines' fraction, commonly refered to as lunar dust. As
reported by McKay and Carrier, this fraction of the