Reactive Oxygen Species (ROS) detection in planetary regoliths, soils and ices with the OxR device
Creators: name:  C. GEORGIOU 
name:   E. KALAITZOPOULOU  
name:   P. PAPADEA 
name:   M. SKIPITARI 
name:   A. VAREMMENOU 
name:   E. CHATZITHEODORIDIS 
name:   A. THOMA 
name:   H. STAVRAKAKIS 
name:   A. KAPAGIANNIDIS 
name:   I. MARKOPOULOS 
name:   D. PLATANOU 
name:   A. ALEXANDROU 
name:   M. HOLYNSKA 
Publisher: name: Proceedings of  the 9th European Conference for Aerospace Sciences. Lille, France, 27 June - 1 July, 2022
Year: 2022
Subjects: SPACE EXPLORATION
ISRU

description: Intense irradiation of planetary surfaces from the Suns UV rays, from cosmic rays, as well as from the fine fracturing of minerals when bombarded by micrometeorites is a continuous process that induces the formation of Reactive Oxygen Species (ROS). ROS are metal superoxides (in the form of O2, such as KO2, NaO2), peroxides (in the form of O22?, such as Na2O2, K2O2, MgO2, CaO2, releasing H2O2 upon H2O-wetting), and hydroxyl radicals (OH). The oxygen release firstly observed on the Martian soils during the Viking Label release biological experiment is now attributed to be an abiotic process due to the presence of ROS in the regolith materials and not from putative microorganisms[1]. Experiments on desert soils from Atacama show that ROS can be produced by photochemical reactions from the Suns light[2]. Perchlorate salts are now known to be present on Mars[3], also a result of the same phenomenon. The OxR device is a novel, small footprint, fully automated device which measures ROS in planetary soils and regoliths. It is temperature- and pressure-controlled system that is based on microfluidic technologies, with reagent reconstitution and delivery parts[4]. A main component is the integrated solid-state optical sensing O2-electrode with an ultralow detection limit (1 ppb) which measures the oxygen that is released and dissolved in the water after its reaction with ROS that is present on the mineral surfaces of the soils. To investigate ROS in detail, we have used pure mineral powders and dusts of rock regolith simulants (i.e., anorthosites or basaltic powders), which we have synthesised and irradiated in the lab, and we plan to use Lunar meteorites and Lunar rocks. We have also implemented a spectrofluorometer to measure concentration of OH. The existence of ROS species is used as an indication of the absence of living organisms, but also the absence of biosignatures in planetary surface soils. This is because ROS are highly reactive with organics and therefore toxic to organisms, including humans. Similarly, the OxR device can also be used to identify ROS on other planetary and icy worlds, such as, Titan, Europa, Enceladus. Considering habilitation of Mars, the use of ROS will serve to identify soils for crop cultivation or to select areas where humans can settle down. In spaceships it can monitor toxic ROS development that is induced by cosmic radiation on the walls, or in the food and water storage tanks. Terrestrial applications again include agriculture, especially on arid or overcultivated areas, or those affected by climate change. ROS is very well known to exist in mining areas, since it is naturally produced on some mineral surfaces; it is toxic to employees and therefore it should be monitored. This research work was performed at the National Technical University of Athens and University of Patras under a programme of, and funded by, the European Space Agency (contract number 4000136482/21/NL/GLC/ov). However, the views expressed herein can in no way be taken to reflect the official opinion of the European Space Agency and are not intended to endorse particular technologies, companies, or products. [1] Lasne, J., Noblet, A., Szopa, C., Navarro-Gonzalez, R., Cabane, M., Poch, O., Stalport, F., Francois, P., Atreya, S.K., Coll, P., 2016. Oxidants at the surface of Mars: A review in light of recent exploration results. Astrobiology 16, 977996. https://doi.org/10.1089/ast.2016.1502 [2] Georgiou, C. D., H. J. Sun, C. P. McKay, K. Grintzalis, I. Papapostolou, D. Zisimopoulos, K. Panagiotidis, G. Zhang, E. Koutsopoulou, G. E. Christidis and I. Margiolaki (2015). Evidence for photochemical production of reactive oxygen species in desert soils. Nature Commun. 6: 7100. [3] Georgiou, C. D., Zisimopoulos, D., Kalaitzopoulou, E., Quinn, R. C. (2017). Radiation driven formation of reactive oxygen species in oxychlorine containing Mars surface analogues. Astrobiology 17(4), 319-336. [4] Georgiou, C.D., McKay, C.P., Quinn, R.C., Kalaitzopoulou, E., Papadea, P., Skipitari, M., 2019. The Oxygen Release Instrument: Space mission reactive oxygen species measurements for habitability characterization, biosignature preservation potential assessment, and evaluation of human health hazards. Life 9, 70. https://doi.org/10.3390/life9030070