Synthesizing Mars: Advancements in Simulant Lithology for Astrobiological and ISRU Studies

The study of astrobiology, in particular testing concepts for searching for biosignatures in extraterrestrial environments or conducting experiments for survivability of microorganisms in extraterrestrial materials and conditions, but also the branch of science and engineering focusing on testing instruments in planetary environments or identifying materials and energy resources (ISRU), both require analogue studies with simulated extraterrestrial materials. Thus, the development of accurate and representative simulant regoliths and soils is crucial [1]. In this study, we present new Martian simulants that have been developed to expand the suite of available lithologies and compositions, while also try to address limitations of previous simulants.

Extensive research has been conducted by our team to analyze the chemical and physical properties of martian surface datasets, including their mineralogy, grain size distribution, and chemical composition. [2], [5], [6]. Thus, our new Martian simulants have been developed to better represent the unique geological and mineralogical features of specific locations of the martian surface. We have used XRD, SEM-EDS, and LIBS analysis to verify the accuracy of our simulants to the reference target compositions. The additions of those new simulants, and their characterisation steps, provide valuable insights for developing even more accurate simulants of the varied geological and environmental conditions of current and early Mars.

Our approach to simulant fidelity and quality involves firstly the reproduction of the accurate mineralogy, which can finally be expressed in chemical terms using an arithmetic quality value, the Figure of Merit (FoM) [3],[4]. This is a standardized fidelity compositional comparison of the oxide differences with the compositions of the reference datasets. In this FoM the grain size distribution and other parameters are not included. The same FoM system is also used to compare our different simulant batches in order to ensure consistency in their production. A constant increase in FoM is achieved in each consequent batch of simulants produced in our lab, with values exceeding 90% of FoM. These values provide confidence in our methods since it provides a way to increase the fidelity of the simulants.

In this presentation we will discuss the methodology and tools we use to achieve the above results, aiming to more representative lithologies, compositions and textures. For each new simulant, we also address the potential impact on specific fields of research, such as their compatibility for either ISRU research, or for astrobiological investigations. We envisage that with further research we can cover the requirements for simulants of new research studies, addressing topics such as planetary evolution and habitability.

1. G. H. Peters et al. (2008), Icarus 197, 470-479.
2. H.-A. Stavrakakis et al. (2022), EPSC2022.
3. C. Schrader et al. (2009), 47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, p 755.
4. L. E. Fackrell, et al. (2021). Icarus 354, 114055. 
5. D. Argyrou et al. (2023), EANA23. “Characteristics of Greek Martian and Lunar Simulants: Insights from the initial development”
6. Georgiou C. et al. (2023), EANA23. “OxR: A novel device for Reactive Oxygen Species (ROS) detection for astrobiology and planetary research”