My master’s thesis was centered on characterizing the expected time on orbit at ISS altitude and inclination before several space-grade silicones (RTV-S691, CV-2960, and DC 93-500) were predicted to form a glassy silicate surface layer using lab testing and statistical regression techniques.
I taught the laboratory section for Cal Poly’s Space Environments required courses for third-year students in the astronautics program in 2024-2025. I also designed, fabricated, and tested three vacuum effusion cells for use in the test chambers, along with developing test protocol for their use in future lab experiments.
In addition to required coursework, I specialized in the Space Environments and Thermal Control subsystems during our year-long capstone senior design project, a theoretical Earth-observing mission in an SSO orbit at 700 km altitude. I helped characterize the loading, material selection, and mitigation for thermal and environmental effects on the proposed 5-year lifetime spacecraft. Below are some examples of my contributions.
Space Environments I. Effects of the space environment on a spacecraft and design considerations. Lecture and laboratory topics include the launch, vacuum, neutral and particulate environments.
Space Environments II. Effects of the space environment on a spacecraft and design considerations. Lecture and laboratory topics include the radiation, plasma, and thermal environments and the synergistic effects.
Master’s Thesis: Investigation Into Silicone-Silicate Conversion Due to Atomic Oxygen in the Low Earth Orbit Environment
Abstract
Silicones have been widely used over the years in spacecraft for a variety of functions, but atomic oxygen (AO) exposure in Low Earth Orbit causes a silicate (SiO2) surface layer to rapidly develop on the silicone which results in a permanent change in its thermal and optical properties. Although this silicone to silicate conversion is known to occur, statistical predictions of layer formation as a function of time on orbit are not found in literature. This thesis utilized optical and scanning electron microscopy, Fourier-Transform Infrared Spectroscopy, diffuse reflectance spectroscopy, and nonlinear regression statistical techniques after RF plasma asher exposure tests to study this phenomenon. Samples were exposed to AO fluences ranging from 2.83 ± 0.214 ×1019 to 1.88 ± 0.0520 ×1021 atoms/cm2. The estimated time at the International Space Station altitude and orbit for CV-2960 and RTV-S691 silicones to form a fully-developed silicate layer is predicted to be between four to nine days, depending on the solar activity. Percent of sample surface area occupied by cracks ranged from 0% to 52.8% and was found to follow a logarithmic model for both CV-2960 and RTV-S691 silicones (R2 = 0.974 and 0.981, respectively) and was significantly linked to AO fluence (p < .0001). CV-2960 silicone was observed to develop a surface silicate layer more readily than the phenyl-containing RTV-S691. Ground-exposed DC 93-500 samples were compared to DC 93-500 MISSE-6 flight articles and were observed to correlate very well in diffuse reflectance features at similar fluence values. Phenyl-containing silicones may be more resistant to AO-induced silicate layer formation which leads to a longer time on orbit before this layer becomes saturated with crack structures.
Spacecraft Contamination
My independent work on this project focused primarily on the contamination section; although I contributed to the AO and MMOD sections.
Course: Senior Design
Thermal Control System
My work focused mostly on the thermal circuit diagrams, thermal environment, radiation design and analysis, orbital mechanics model; although I contributed heavily to the simulations and MLI layering design.
Course: Senior Design