Available at: https://digitalcommons.calpoly.edu/theses/3131
Date of Award
6-2025
Degree Name
MS in Aerospace Engineering
Department/Program
Aerospace Engineering
College
College of Engineering
Advisor
Kira Abercromby
Advisor Department
Aerospace Engineering
Advisor College
College of Engineering
Abstract
As the orbital debris population increases, so does the risk of collisions with operational spacecraft. In response, the Federal Communications Commission has shortened the deorbit requirement from 25 years to five years. While natural atmospheric decay was sufficient under the previous guideline, many objects with low area to mass ratios can no longer passively comply. Smaller, non-propellant-carrying space objects such as CubeSats lack the ability to maneuver and must rely on alternative deorbit methods. One proposed solution is to deploy a drag sail at end of life to increase atmospheric drag and accelerate orbital decay. However, exposure to atomic oxygen (AO) in the low Earth orbit environment degrades the thin membrane of the sail, compromising its functionality. This study investigates the survivability of single-sided aluminized Mylar® exposed to AO, generated by a capacitively coupled plasma system, and vacuum ultraviolet radiation (VUV) from a deuterium lamp. Forty-nine AO tests were conducted: 16 with the aluminized side exposed and 33 with the uncoated side. Fluence was calculated using the mass loss of a Kapton® HN witness sample, and each Mylar® sample was evaluated for survival. Two tests exposed samples to both VUV and AO, but no additional deterioration as a result of VUV was observed at the tested exposure levels. Binary logistic regression was used to develop an inverse prediction model for Mylar® survival as a function of AO fluence. The aluminized model showed a better fit than the uncoated model. Based on this analysis, a drag sail deorbit simulation was developed that models degradation due to AO. Given the poor fit of the uncoated model, only the data from the aluminized side was used; consequently, the simulation assumes perfect pointing accuracy. The model simulates degradation in 10% increments from full sail area to complete loss and is validated against the orbital decay of NanoSail-D2. Results show that deorbit time is highly sensitive to both initial sail size and solar activity.