Design of the Martian far-IR ORE Spectrometer MIRORES

Jakub Ciazela ¹ Jaroslaw Bakala ¹ Jaromir Barylak ¹ Marta Ciazela ¹ Miroslaw Kowalinski ¹ Stefan Plocieniak ¹ Joanna Gurgurewicz ¹ Daniel Mege ¹ Bartosz Pieterek ² Zaneta Szaforz ¹ Pierre-Antoine Tesson ¹ Marco Giuranna ³ Franco Pirajno ⁴

¹Space Research Centre, Polish Academy of Sciences, Warsaw, Poland, Poland
²Institute of Geology, Adam Mickiewicz University, Poznań, Poland
³Instituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica, Roma, Italy
⁴Centre for Exploration Targeting, The University of Western Australia, Perth, Australia

Sulfide ores are a major source of noble metals (Au, Ag, Pt) and base metals (Cu, Pb, Zn, Sn, Co, Ni, etc.), and therefore will be vital to self-sustainment of future Mars colonies. Martian meteorites are rich in sulfides, which reflects in recent findings from Martian rovers. Yet the only high-resolution (18 m/px) infrared spectrometer orbiting Mars, CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) on board Mars Reconnaissance Orbiter (MRO), struggles to detect sulfides on the martian surface. Spectral interferences with silicates impede sulfide detection in the 0.4-3.9 µm CRISM range. In contrast, at least four common sulfides on Earth and Mars (pyrite, chalcopyrite, marcasite, pyrrhotite) possess prominent absorption peaks in a narrow far-infrared (FIR) wavelength range of 23-28 µm.

Providing global distribution and chemical composition of sulfide ores would help to choose useful targets for future Mars exploration missions. Therefore, we are starting to design a relatively cheap and simple pyroelectric detector-based Martian far-IR ORE Spectrometer (MIRORES) measuring three wide spectral bands limited with filters, including the main band of 23-28 µm and two reference bands at 18-21 µm and 35-40 µm. Focusing on sulfides only will allow reducing instrument dimensions to the microsatellite size. The largest challenge related to this design is the small field of view conditioned by high resolution required for this study (10-20 m/px), which in limited space can be only achieved by the use of the Cassegrain optical system. The probe might be launched as a piggyback mission with a larger satellite (for example Japanese Martian Moons Exploration) during the 2024 or 2026 Mars launch window.