The last decade of Martian surface exploration has increased knowledge of the composition and variability of minerals present in the regolith and bedrock. This informs planning for manned missions to Mars for which these surface materials may be an important in-situ resource in agricultural applications. Soil on Mars is known to contain the majority of planet essential nutrients, but many questions of both the benefits (e.g. bioavailability of present nutrients) and limitations (e.g. extent of toxins) of Martian soil as a plant growth medium remain unanswered. It may be necessary to augment Mars soil with other regolith and bedrock materials (e.g. phyllosilicates, carbonates) to produce a medium appropriate for plant growth. A better understanding of the feasibility of using Mars soil as a plant growth medium could be accomplished with methods common to agricultural practices on Earth (e.g. biofertilization) using appropriate regolith and bedrock simulants as a plant growth medium. The study herein discusses the development of five new regolith and bedrock simulants. These simulants are designed to reflect several mineralogical (e.g. phyllosilicate clays) and chemical characteristics of various Mars surface materials that are most relevant to establishing the potential and limitations of these materials as in-situ resources for agricultural applications. The use of simulants provides a test bed for studies examining the potential of Mars' regolith and bedrock in agricultural applications, understanding data gaps surrounding these materials that will need further characterization, and methods to then conduct needed characterization of true Martian-regolith and bedrock in-situ. The simulants discussed herein are analyzed by X-ray diffraction using Reitveld refinement, X-ray fluorescence, V/NIR reflectance spectroscopy, and 57Fe Mössbauer spectroscopy and then compared to equivalent published data available from Mars rover and orbiter missions. The resulting simulants are chemically and mineralogically comparable to Martian regolith and bedrock and reflect data particularly relevant for growing plants on Mars. The developed simulants are relevant for analogue plant growth studies and fertility measurements that may inform hypothesis, habitat design, and mission plans which involve using Martian soil as a plant growth medium.
Fackrell, Laura E., Paul A. Schroeder, Aaron Thompson, Karen Stockstill-Cahill, Charles A.Hibbitts (2020): Development of Martian regolith and bedrock simulants: Potential and limitations of Martian regolith as an in-situ resource. Icarus 354: 114055. DOI: 10.1016/j.icarus.2020.114055
This Paper/Book acknowledges NSF CZO grant support.