Absorptivity and Emissivity Measurement Error Characterization of Protective Methods for Optical Property Instruments

The Artemis campaign has reemphasized the concern of lunar regolith and its influence on vehicles and equipment. Recent studies from Johnson Space Center show that dust forms non-uniformly on surfaces, causing substrate to be visible through the dust layer even as thickness increases. The dust formation alters the overall solar absorptivity and infrared emissivity of the surface, which can negatively impact heat rejection capabilities. Currently, there is no standard method to measure the properties of dust particulates with standard optical equipment, as the open instrument sources are at high risk of contamination. A preliminary study was completed using generic plastic wrap to protect the instrument source but showed high comparison error in wavelength values and destroyed the delicate dust structures. In this study, multiple types of transmissive films and glasses will be used with an apparatus to protect the source and preserve the dust structures. The error between the raw and protected measurements will be compared for each individual method. These methods will also be tested on a wide array of common space materials and coatings to characterize any remaining error with the best overall performing protection method.