Standard Lunar Regolith Simulants for Space Resource Utilization Technologies Development: Effects of Materials Choices

Introduction: As NASA turns its exploration ambitions towards the Moon once again, the research and development of new technologies for lunar operations face the challenge of meeting the milestones of a fast-pace schedule, reminiscent of the 1960's Apollo program. While the lunar samples returned by the Apollo and Luna missions have revealed much about the Moon, these priceless materials exist in too scarce quantities to be used for technology development and testing. The need for mineral materials chosen to simulate the characteristics of lunar regoliths is a pressing issue that is being addressed today through the collaboration of scientists, engineers and NASA program managers. The issue of reproducing the properties of lunar regolith for research and technology development purposes was addressed by the recently held 2005 Workshop on Lunar Regolith Simulant Materials at Marshall Space Flight Center. The recommendation of the workshop of establishing standard simulant materials to be used in lunar technology development and testing will be discussed here with an emphasis on space resource utilization. The variety of techniques and the complexity of functional interfaces make these simulant choices critical in space resource utilization. Standard Lunar Regolith Simulants (SLRS): A lunar simulant is manufactured from terrestrial components for the purpose of simulating one or more physical and chemical properties of the lunar regolith. A root simulant represents an end-member in terms of simulant properties, and a derivative simulant is formed from a root by modification or addition of material [1]. The degree of duplication of soil characteristics in the simulant is the simulant fidelity. The 2005 Workshop recommended production of two root simu-lants corresponding to a low-Ti mare basalt and a high-Ca highland anorthosite. These roots represent compositional end-members of mare and highland materials , and can in principle be physically mixed to target the range of soil compositions in the Apollo inventory. Specific lunar regolith properties can be addressed by addition of ilmenite, glassy agglutinates, nanophase iron, and other materials [2]. The fidelity of root simulants is thus increased by addition to form derivative simulants. While the larger size fraction of 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