P068-0002
Evaluation of a sample handling protocol for reliable laboratory space weathering simulations via ion irradiation and in situ characterization of olivine powders

Tuesday, 15 December 2020
Poster
Camilo Jaramillo1, Jean Paul Allain1, Daniel Wolf Savin2, Neil Pearson3, Deborah Lorin Domingue4 and Amanda R Hendrix5, (1)Pennsylvania State University Main Campus, Nuclear Engineering, University Park, PA, United States, (2)Columbia University, New York, NY, United States, (3)Planetary Science Institute Tucson, Tucson, United States, (4)Planetary Science Institute, Tucson, AZ, United States, (5)Planetary Science Institute Tucson, Tucson, AZ, United States
Abstract:
The Toolbox for Research and Exploration (TREX, trex.psi.edu), a node of NASA Solar System Exploration Research Virtual Institute (SSERVI), aims to develop tools and research methods for exploration of airless surfaces in preparation for human and robotic in situ resource utilization (ISRU) missions. This work focuses on conducting reliable laboratory space weathering simulations as a tool to support the analysis of data from remote sensing observations of airless bodies. This is achieved by ion irradiation of olivine powders handled under inert environments to inhibit sample contamination and recording X-ray Photoelecton Spectroscopy (XPS) and reflectance spectra in situ.

The study of airless bodies in our solar system relies enormously on remote sensing. Analysis of reflected spectra in the ultraviolet, visible , and infrared wavelengths from these bodies can provide information about the mineralogic composition of the immediate surface (100 µm). Airless bodies are constantly subject to bombardment by energetic ions and electrons from the solar wind and solar flares, micrometeorites, photons, and cosmic rays [1], altering the physical and chemical properties of the surface (102 nm), in a process called space weathering [2,3]. The influence of weathered surfaces on the characteristics of reflected spectra is still a matter of debate.

Laboratory simulations allow to understand the nature of these surface changes and accurately interpret data from remote sensing. Simulations on minerals include bombardment with high energy ions and solar wind-like ions [4]. Reliable laboratory simulations of space weathering by solar wind require: (1) regolith-like loose powders, (2) sample manipulation in controlled environment to limit surface contamination, (3) ion irradiation under solar wind conditions, and (4) in situ diagnostics including reflectance spectroscopy.

Here we present the results of laboratory space weathering simulations performed on olivine powders, conducted at the IGNIS facility. Different sample handling protocols (air, inert environment and vacuum) were followed to evaluate the influence of surface exposure to air. Deuterium and argon ion irradiation were carried out, at fluences up to 1x1019 cm-2. XPS and reflectance spectra were recorded in situ to assess the influence of ion bombardment on the surface chemistry changes and the reflectance spectra characteristics.

[1] B.E. Clark, R.E. Johnson, Eos 77 (1996) 141-5. [2] T.E. Madey, R.E. Johnson, T.M. Orlando, Surf. Sci. 500 (2002) 838-858. [3] C.R. Chapman, Annu. Rev. Earth Planet. Sci. 32 (2004) 539-567. [4] C.J. Bennett, C. Pirim, T.M. Orlando, Chem. Rev. 113 (2013) 9086-9150.

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