Development of a Polar Regolith Environment Molecular Impact Simulation Experiment (PREMISE), 15-R8241
Principal Investigators
Ed Patrick
Ben Teolis
Greg Miller
F. Scott Anderson
Inclusive Dates: 07/01/11 – Current
Background — The discovery of pit craters on the lunar surface and of volatiles trapped at the lunar poles has created a renaissance in lunar science. The motivation for this project was the desire to develop a laboratory space environment simulation of the lunar polar regolith. The intended purpose of this laboratory system is not only to study the conditions at the lunar surface, but also to aid in the design of the "front-end" components for a landed lunar mass spectrometer. Any proposed instrument for a future lunar surface mission must have a high technical readiness level (TRL) and show a capacity for maximizing the science return from investigations of the volatiles trapped within the lunar regolith. These materials may not only reveal the ancient volatile history of the inner solar system, but they may also represent resources (e.g., water) critical to the future of lunar outposts and the prolonged presence of humans at the lunar surface.
Approach — A lunar regolith simulant known as JSC-1A was placed within a vacuum system and exposed to various volatiles and gases (H2O, CO2, N2, Ar) while the system was monitored by a mass spectrometer. The JSC-1A simulant is a dark, finely-ground, powder-like, basaltic material. It was processed in air by a proprietary mechanical technique from basaltic ash at the foot of a thousand year-old extinct volcanic cone in Arizona. The capacity of the simulant for entrapping gases at various temperatures and gas exposure pressures are being monitored. Laser ablation, ion and mechanical techniques will be employed as means for producing suitable vapor plumes for monitoring evolved gas constituents by mass spectrometry. A preliminary design will be drafted for a landed mass spectrometer based on the results of this investigation for inclusion in future proposals targeting investigations of the lunar surface environment.
Accomplishments — Though the introduction of the JSC-1A lunar soil simulant into an ultrahigh vacuum (UHV) system has been a problematic process owing to the large surface area of the material, preliminary data are intriguing and suggest multiple gas-trapping effects that may be analogous to, and appropriate for, future studies of the lunar surface environment. The mass spectrometric analysis of the JSC-1A simulant in vacuum is currently focused on four gas processes that may affect the evolution and behavior of the material under exposure to gases and volatiles: (1) the original entrained gases and volatiles within this refractory oxide-rich basalt as it reached the surface of the Earth, (2) exposure of this basaltic material to gases and volatiles when it was ejected and cooled during the volcanic eruption process, (3) exposure of this material to terrestrial gases and volatiles during long-term weathering processes in terrestrial air, and (4) the subsequent processing that crushed this material and exposed it to gases and volatiles in terrestrial air. SwRI researchers are currently studying the interaction of the simulant with various gases in order to separate terrestrial material effects from those anticipated in future studies of the lunar surface. SwRI researchers have also determined that minimal energy is necessary to produce gas plumes sufficient for analytical techniques (e.g., mass spectrometry) for detecting and analyzing volatiles in the JSC-1A lunar regolith simulant. The PREMISE project helped support the submission of a NASA Research Opportunities in Space and Earth Sciences (ROSES) Lunar Advanced Science and Exploration Research (LASER) proposal by the same name ("PREMISE") that is currently pending. This project reduced program risks related to the handling of lunar regolith simulant in the laboratory and improved the technical maturity of the LASER proposal submission to NASA.
