QUANTITATIVE REFLECTANCE IMAGING FOR SAMPLES OF ASTEROID BENNU

Abstract

My honors thesis focuses on the design of a laboratory-based spectral imaging system for use in analyzing the sample of Bennu that will be returned to Earth by OSIRIS-REx in Fall 2023. I assess multiple cameras for their ability to create sciencequality images of the sample and distinguish between Bennu’s two distinct lithologies. After researching several cameras, I selected the Allied Vision Alvium 1800 U-2040m camera, which has a resolution and dynamic range suitable for gathering detailed quantitative reflectance data. While researching cameras, I worked on building a primitive lighting and imaging system as a qualitative proof of concept for the final quantitative spectral imaging system that will be installed at the Johnson Space Center. The primitive system was used at the 2022 Sample Analysis Science Operations Proficiency Integrated Exercise 1 (SOPIE-1) to image a rock sample of unknown composition under several wavelengths of light. Through analysis of the SOPIE-1 images, the OSIRISREx team identified six of the eight unique lithologies present in the sample. Following the SOPIE-1, I wrote Python scripts to conduct further image analysis and identified a candidate stone to represent one of the missing lithologies. More sophisticated analysis is needed to confirm the stone’s properties. The success of the SOPIE-1 suggests that a similar system with a more sophisticated camera, mount, and software will be sufficient for the SOPIE-2 and the real Bennu sample analysis. The detector, lighting, and optics procured during this project will be key components in producing science-quality images at the SOPIE-2.