Speaker
Description
Title: Sensing and Modelling Planetary Dust Reactive Oxygen Species (ROS) and their Effects on Space Missions by High-Fidelity ROS-Activated Dust Simulants
Christos D. Georgiou M.Sc., Ph.D.1 and Elias Chatzitheodoridis M.Sc., Ph.D.2
1,2 Co-Chiefs of Science & Technology Innovations & Operations, Stellar Discoveries, Greece
1 Oral presentation
Abstract
Reactive Oxygen Species (ROS: superoxide radicals, O2•−, hydroxyl radicals, •OH, hydrogen peroxide, H2O2) are constantly generated in dusts (planetary or cosmic) of our Solar system, as demonstrated by direct observations and experiments with planetary dust simulants. Planetary dusts that produce ROS can have a negative impact on missions to Mars, the Moon, Europa, Enceladus, the ISS, and the GSS, as well as a positive impact on other missions. For the former, they can compromise astronaut health, oxidatively deteriorate payload instruments and sensors, and pollut space station inner/outer habitats, destroy biosignatures for alien life search etc. For the latter, dusts selected for sample return missions should be properly handled to preserve the naturally occurring ROS activation for valid simulation studies, and their ROS can be used as O2 source for astronaut support (by O2-harvesting technologies such as our “OxR-From Reactive Oxygen Detection to Oxygen Farming” project; https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Moon_and_Mars_superoxides_for_oxygen_farming), even for monitoring/prognosing Moon/Mars quakes. ROS contamination of space missions by planetary dusts can be modelled by the development of ROS-activated dust simulants. We can produce high-fidelity dust simulants with various types of ROS activation by a process that subjects their mineral source to a high thermal/kinetic energy impact, analogous to high energy impacts on planetary regolith by meteorites. Such thermal/kinetic process enables the simulated planetary dusts to acquire ROS activation of the following types, which are novel, and previously not identified and quantified by chemical means: (I) ROS activation embedded in the simulated dusts during their formation, of the following ROS activation sub-types: a) MEtal OXide Reactive Salts (MEOXRS), composed of metal salts of the ROS superoxide radical (O2•−) and peroxide (O22−); b) Fe-II Reactive Impact Glass (FeRIG), made by Fe2+-rich grains of iron nanoparticles (np-Fe°) that are distributed on the surface of the resulting impact glass spherules/agglutinates. (II) Intrinsic ROS activation potential generated on the surface of the fractured particles of the simulated dust, which is caused by the formation on their surface of silica free radicals, negative and positive charges. MEOXRS, FeRIG, intrinsic ROS activations can be complemented, on demand, with additional Perchlorate Reactive Chlorine Species (PERCS) and Pyrite (FeS2) and Iron Sulfide (FeS) ROS activations, specific for Mars and Moon dust simulants. Existing/commercially available simulants, are (i) dust analogues, which may possess partial intrinsic activation potential, (ii) artificially generated (e.g., by UV exposure, fresh grinding), and (iii) lacking chemical identification and quantification (the latter can be addressed by unique analytical tools of ours). ROS-activated dust simulants can be used to model, using specific ROS sensors of ours (calibrated on the dust simulants), the identification and quantification of the ROS components induced by planetary dusts, which pollute any space environment, mission, base/station, astronauts, equipment etc. The sensors (microfluidic for mission deployment) are the aforementioned and ESA-IDEAS-funded, (i) OxR (at TRL4) and (ii) LunarDBCR (“Lunar Dust Biotoxic Chemical Reactivity”; under development at TRL4), which identify/measure the ROS O2•−/H2O2, and •OH, correspondingly, and also the (iii) PERCS sensor (ready for development) that identifies/measures the PERCS HClO/ClO−. Having specifically identified the ROS/PERCS that affect space missions, these can be, then, eliminated by specific, non-toxic/corrosive, antioxidant chemicals (Georgiou NASA-2022 NOI no N1-21RFISRNom-0006).
