Elke, William2023-11-302023-11-302023-08https://hdl.handle.net/11299/258862University of Minnesota Ph.D. dissertation.August 2023. Major: Aerospace Engineering and Mechanics. Advisor: Ryan Caverly. 1 computer file (PDF); x, 134 pages.Current and future missions to send humans to the Moon and beyond will have increasingly strict requirements on the performance and robustness of the mission vehicles. These requirements will push all aspects of the vehicles to advance to ensure mission safety and success. This includes the guidance, navigation, and control (GNC) systems operating on board. Novel GNC systems must be matured in an environment analogous to those they operate in, but these operating conditions are difficult to replicate. The first part of this dissertation presents the Cost- and Risk-Reducing Quadcopter System (CRQS, pronounced "circus"), a platform proposed to provide a low-cost, low-risk setting to mature novel GNC systems. The system is modeled, then implemented in numerical simulations to analyze a control system's ability to track a generated trajectory. The work done to fabricate a physical flying inverted pendulum, a necessary step to reach the complete CRQS, is then presented. As spacecraft grow to accommodate larger payloads and more distant destinations, the amount of liquid propellant on board grows. The interactions between a spacecraft and the liquid propellant can have detrimental effects on the performance of the spacecraft's GNC systems. The second part of this dissertation develops a low-order approximate dynamic model of a spacecraft and its liquid onboard propellant in a low-g environment. The model is then implemented in numerical simulations to analyze the trajectory of the Apollo-era service module (SM) for the probability of recontact after jettison from the command module (CM).endynamic modelingtrajectory optimizationverification & validationThesis or Dissertation