Abstract

Reflectance modeling of specular surfaces with irregular geometries remains difficult to solve for an array of applications. In the growing space industry, there are many spacecraft materials with high specularity and varying levels of roughness. Modeling these materials in simulations becomes difficult as any realistic amount of roughness is added, necessitating more accurate physical models to represent how light is interacting with these surfaces. While some work has been done to attempt to characterize the spectral signatures of the materials themselves using hyperspectral imaging systems, the scope of these efforts has been fairly limited and not representative of the conditions of on-orbit spacecraft geometries. Many models that attempt to characterize reflectance from roughness do not account for the effects of multiple-scattering of light due to the surface geometry, and the few that do only provide empirical solutions to the problem for specific scenarios/materials. There are multiple approaches that attempt to account for multi-facet scattering (typically Fresnel/specular models vs. those that consider diffusely scattered light), but none are exact. This has to do with each approach’s ability to account for both diffuse and specular scattering due to directional light. Using spacecraft Multi-Layer Insulation (MLI) materials with varying levels of roughness applied to each, the Bidirectional reflectance distribution function (BRDF) of each material in each roughness state was collected at multiple illumination angles in order to gather enough data to fit a recently developed model from the literature and to propose adjustments to said model. Through a discussion of the effectiveness of the model’s components accounting for single and multiple scattering, as well as the nature of the materials themselves in roughened conditions, a path forward for modeling such roughened specular materials is identified for the future capability of accurately modeling and simulating such scenarios.

Library of Congress Subject Headings

Reflectance spectroscopy; Artificial satellites--Modeling; Surface roughness; Light--Scattering

Publication Date

7-14-2025

Document Type

Thesis

Student Type

Graduate

Degree Name

Imaging Science (MS)

Department, Program, or Center

Chester F. Carlson Center for Imaging Science

College

College of Science

Advisor

Charles M. Bachmann

Advisor/Committee Member

Michael Gartley

Advisor/Committee Member

Carl Salvaggio

Comments

This thesis has been embargoed. The full-text will be available on or around 7/30/2026.

Campus

RIT – Main Campus

Plan Codes

IMGS-MS

Download

Available for download on Thursday, July 30, 2026

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