Future long duration exploration missions (LDEMs) conducted by NASA will have an increased need for crew autonomy during routine and emergency procedures due to the increased distance from Earth causing time delays in communications. Presently, ISS in-space tasks are completed by astronauts using simple text-based procedures supplemented with real-time communication between the crewmembers and mission control personnel. As LDEMs require increased crew autonomy, more information must be stored on-board such that it can be accessed by crewmembers in a timely and context-appropriate manner during procedure execution. Emergent technologies in multimodal interactions such as Internet-Of-Things (IoT) sensors and enhanced visual displays are likely to play essential roles in safe crew-autonomous procedure execution. With this in mind, two studies were conducted: a study in NASA HERA to test enhanced multimodal procedures in a spacecraft analog environment, and a Davis study to determine how individual multimodal enhancements affect task performance. The goal was to determine how subjects’ task performance on a complicated manual repair task differed between enhanced procedures and traditional unimodal PDF procedures. An Enhanced Procedure Viewer system was developed that provided a variety of procedural enhancements: step navigation, enhanced visuals, real-time sensor feedback, and laser guidance. Results concluded that different enhancements in the multimodal procedure could decrease task completion time, increase task completion accuracy, decrease subjects’ perceived workload, and increase the level of trust subjects had in the procedure system.

This thesis presents a conceptual design for a tilted-airframe unmanned aerial vehicle (UAV) that aims to address the challenge of detecting infected citrus trees by Huanglongbing (HLB) using a remote air sampling method. The tilted-airframe UAV is capable of vertical take-off and landing (VTOL) which can vertically take off and land in an orchard between trees and deploy an extendable boom to collect an air sample for HLB disease detection. The tilted-airframe UAV design is based on a tri-copter airframe with three key modifications: tilted-airframe, a novel moment (yawing and rolling) governing system, and a fixed-wing. When the UAV operates in VTOL mode, the airframe of the UAV is pitched up 45 degrees from the horizontal direction. The tilted-airframe concept simplified the UAV’s mechanism design, with all motors fixed relative to the airframe and the whole airframe tilting during the flight mode transition. Furthermore, the tilted-airframe UAV utilizes a butterfly flap system on each side of the wing to control attitude and allows for constant RPM with fixed-pitch propellers during both hovering and the transition to cruise mode. The addition of a fixed-wing increases flight endurance, range, and cruise performance compared with a conventional multi-copter UAV. However, the tilted-airframe with a fixed-wing brings potential challenge for a stable hovering under wind disturbance and the power efficiency is not as good as a conventional fixed-wing UAV. Overall, this thesis explores the development of a tilted-airframe UAV for air sampling and HLB detection in citrus trees, focusing on the transition from hover to cruise mode, flight motion prediction, data collection, comparison, and cruise performance estimation.

The objective of this thesis is to systematically develop the underlying theory behind and implementation of an integrated framework for analytical multibody dynamics modeling and closed-loop simulations with novel control strategies for the powered-descent and precision landing of rocket-powered space vehicles.The thesis is organized as follows: Chapter 1 provides an introduction to the rocket-landing problem and the motivation for developing new methods and algorithms to enable future planetary landing missions. Chapter 2 describes the implementation of a globally-optimal minimum-propellant powered-descent guidance (PDG) algorithm using lossless convexification and convex optimization. Chapter 3 explains the analytical formulation of the nonlinear equations of motion for a variable-mass multibody rocket system using the extended Kane’s equations, and shows results from an open-loop simulation run with the optimal control commands obtained from guidance. Chapter 4 describes feedback control in detail, including a novel method for the design of internally stabilizing multivariable robust feedback controllers using Youla parameterization, along with its application to the underactuated lunar landing problem with feedback control only. Chapter 5 provides an algorithm for the design of internally stabilizing robust LPV controllers via Youla parameterization and applies it to the underactuated lunar landing scenario in a combined feedforward-feedback control architecture with propellant-optimal guidance, control allocation, and various actuator considerations. Chapter 6 concludes the thesis with key observations regarding the work done, the results obtained, the specific contributions, and potential directions for future research.

Without a precedent to laundering clothes off-Earth, a preliminary solution is required to develop a spaceflight laundry machine capable of operating in various gravity fields. With this thesis’ proposed solution, human exercise to power an agitating bladder, a closed-loop hydraulic system, and a wastewater sensor suite provide a desirable environment for quantifying waste-mass transfer away from textiles while minimizing textile damage. Bond Graph Theory is used to model the proposed solution and to evaluate how human-power and valve configurations affect the system’s cleaning performance. Bond Graph simulation results reveal preliminary performance metrics and hardware significantly impacting the machine’s performance. A human-powered laundry machine prototype and model are essential for maturing the technology to spaceflight readiness.

The Environmental Control and Life Support System (ECLSS) of a spacecraft is an integral part of human exploration. Current efforts to advance state of the art ECLSS subsystems in the International Space Station (ISS) are geared towards modeling and simulating various conditions and mission types. NASA and private partners are looking to enable life on the Moon and Mars, and a key factor to enabling that is carbon dioxide (CO2) removal. Astronauts depend on the removal of metabolic CO2 to keep cabin atmosphere at breathable levels which typically utilize adsorbent-based systems. Thus, modeling and simulating carbon dioxide removal aligns with the effort to advance future ECLSS technology while saving cost and time as compared to the traditional design-build-test approach. In addition, modeling and simulation can generate copious amounts of data and benefits research and development into ECLSS diagnostics and prognostics that require masses of data. This thesis aims to provide models of a carbon dioxide removal system that mimic the physical system, test what-if scenarios, simulate faulty and degraded conditions, implement state estimation and describes the development and results of an adsorbent degradation-focused testbed with relevance to deep space habitat settings. Chapter 1 is an introduction to the thesis with focus on the NASA HOME Institute which has funded this work, an overview of ECLSS, a description of CO2 Removal technology, modeling and simulation objectives, and model options and selection for CO2 removal. Chapter 2 provides an extensive literature review of the current status of ECLSS roadmaps, lessons learned, maintenance and spares logistics as well as ECLSS data analysis processes relevant to diagnostics and prognostics applications for deep space habitats. Chapter 3 details the development of a one-bed carbon dioxide removal system using Aspen Adsorption, a ready-made platform with built-in mathematical computations and capabilities for fault injection, to generate a multitude of data signatures, nominal and off-nominal, and validate against experimental data. Next, Chapter 4 describes model development using MATLAB, a mathematical program with full customization and algorithm integration capabilities but challenging development of numerical computations and fault injections, to generate nominal data signatures with the off shoot of applying state estimation to increase the model’s overall ability to combine measurement data with theoretical models to estimate sensor data, whether available or not. Finally, Chapter 5 details the assembly and test of a supplementary carbon dioxide removal testbed focused on sorbent degradation which achieved proof of concept operation and ultimately generated test protocols and documentation for hardware and software improvements for the next generation testbed.

Parachutes are an essential design component of every crewed space vehicle currently in development.Some high-drag parachute designs have the potential to be inherently unstable and undergo pendulum motion in flight, subjecting the crew and cargo to additional hazards during landing. A fundamental understanding of the coupled dynamics and aerodynamics of parachutes is essential in order to design these descent systems safely. Traditionally, parachute design is accomplished through extensive flight and wind tunnel testing, but Computational Fluid Dynamics (CFD) modeling is an advancing tool that has the ability to provide additional insight into this analysis process. State-of-the-art computational techniques like Fluid-structure Interaction (FSI) provide the highest fidelity approximations of parachute flows but do not yet have the same level of confidence in the industry as rigid-body, Reynolds-averaged Navier-Stokes (RANS) CFD. This work applies the reliability and accuracy of structured, overset mesh CFD techniques to the parachute design process by simplifying the simulated parachute as a rigid, nonporous canopy. Validation of the acceptability of these simplifications is achieved through experimental comparison.

The CFD solver OVERFLOW's built-in Geometry Manipulation Protocol (GMP) tool couples the discrete solution of the Navier-Stokes equations with explicit solution of 6-degree-of-freedom (DoF) dynamics equations, enabling relative motion of overset grids driven by integrated aerodynamic loads.This research details a method for utilizing this capability to simulate dynamic pendulum motion of a parachute, driven by the aerodynamics of the massively-separated, bluff-body wake. Validation of the functionality of GMP in modeling constrained, aerodynamically-driven, pendulum motion was established by simulating a 1-DoF, circular cylinder pendulum and comparing the resulting motion predictions to a analogous numerical model derived by assuming a constant drag coefficient for the cylinder. A simple parachute-analog geometry was also simulated in two and three dimensions to demonstrate the model's ability to predict multiple modes of motion driven by unsteady aerodynamics. Accuracies for the parachute pendulum CFD model were established by simulating a high-fidelity, rigid-shell model of the Orion Multi-Purpose Crew Vehicle (MPCV) main parachute, prescribed to move according to a fit equation of the motion observed in a 35%-scale wind tunnel test of the same geometry. Similar magnitude and trends of the unsteady aerodynamic loads were confirmed and CFD model uncertainties were established by comparing relative differences. Finally, a parametric study of the effects of geometric porosity on dynamic stability was performed for the two-dimensional, simple parachute-analog geometry to demonstrate the ability of the model to predict dynamic stability characteristics of new designs.

Reaction wheels play an essential role in the attitude control of small satellites; however, the trade-off between cost and reliability of commercial and in-house manufactured reaction wheels is a common pain point for small satellite developers. Hard disk drives (HDDs) repurposed as reaction wheels (HDD-RWs) are a low-cost, commercial-off-the-shelf (COTS) solution to the cost versus reliability trade-off for small satellite reaction wheels - they are one to three orders of magnitude less expensive than commercial reaction wheels and demonstrate competitive performance. HDD-RWs have the potential to dramatically lower barriers to entry, allowing resource-constrained organizations to develop CubeSat missions with reliable attitude control.

This thesis presents the research efforts to develop, test, and demonstrate the HDD-RW technology. Lab testing of the HDD-RW was performed to identify a working hardware configuration for the HDD-RWs and develop an actuator model. Preliminary environmental testing was conducted to ensure the HDD-RW can survive vibration loads and a vacuum environment. Single-axis ground testing of the attitude controller using the HDD-RWs was performed to verify its performance. Demonstration of three-axis attitude control using the HDD-RWs was performed through microgravity parabolic flight testing. Successful demonstrations of stabilization and pointing of a HDD-RW CubeSat testbed in microgravity environment raised the Technology Readiness Level (TRL) of the HDD-RW technology from TRL 4 to TRL 6. Data from parabolic flight testing is used to perform system identification of the HDD-RWs and CubeSat system. Simulation results based on the system model further demonstrates pointing control with the HDD-RWs for various target attitudes and stabilization from various initial rotation rates. A guide for using HDD-RWs and developing a controller is presented. Recommendations and lessons learned are provided, and next steps for the HDD-RW technology are discussed.

A vital element of any human-rated mission is the Environmental Control and Life Support System (ECLSS), composed of multiple subsystems, including an Air Revitalization subsystem that maintains a breathable atmosphere. Tracking performance, identifying performance degradation, predicting remaining useful life of components, and performing maintenance on such a critical system are paramount to creating a safe, habitable environment and are thus key research areas at the UC Davis Center for Spaceflight Research. This thesis outlines the design, build, and test of the ZeoDe (Zeolite Capacity Degradation) testbed at the UC Davis Center for Spaceflight research, as well as the background research that went into its conception. This testbed is a chemically functional CO2 removal system that generates degradation data for prognostics through the introduction of humidity into the system. The introduction of humidity can occur in a space habitat due to leaks or other faults. Humidity build-up within the system leads to CO2 removal capacity degradation of the sorbent. Thus, the study of sorbent degradation is of paramount importance to any zeolite-based CO2 removal system deployed on future spacecraft. The maintenance of such a system is equally important. The base requirements of the ZeoDe system take both human and robotic maintainability into account, along with the development of a twin robotically manipulable mockup that was also built up at the UCD Center for Spaceflight Research. The ZeoDe testbed will allow UC Davis, NASA, and any visiting researcher to investigate sensor criticality, degradation physics, detection sequences, and maintenance plans for a degraded ECLSS CO2 removal unit in both autonomous robotic tasks and integrated robot/human teaming scenarios. The modular build will also allow for future research and visiting research to take place at the center to further ECLSS research for future space habitation.

This thesis presents the design of a parabolic flight experiment and the development of the supporting systems to demonstrate hard disk drives functioning as CubeSat reaction wheels. Commercially available CubeSat reaction wheels are costly due to their precise manufacturing requirements, flywheel balancing, and limited amount of vendors. University-built CubeSat reaction wheels can prove to be failure-prone and time-consuming due to the expertise and machinery needed to manufacture, assemble, and test each unit. Through three years of research and testing, the Human/Robotics/Vehicle Integration and Performance (HRVIP) Laboratory in the UC Davis Center for Spaceflight Research (CSFR) developed a low-cost, reliable, readily available solution to the CubeSat reaction wheel cost versus risk tradeoff by repurposing hard disk drives (memory storage devices commonly used in laptops) as CubeSat reaction wheels. Testing the Hard Disk Drive Reaction Wheels (HDD-RWs) in parabolic flights allowed for characterization of their performance in the fully unconstrained free-floating environment of microgravity. The design of the parabolic flight experiment system is presented, herein, with a focus on design for human operation and safety in the dynamic flight environment. Five CubeSat testbeds, each containing HDD-RWs, were developed for testing in the parabolic flights, and a supporting computer vision system was designed utilizing ArUco markers for external attitude determination of the CubeSat testbeds. The measurement accuracy and noise of the computer vision system was characterized on-ground through precise placement of the ArUco markers with a UR5e robot arm. Flight data from the computer vision system was integrated into an Extended Kalman Filter and shown to validate the CubeSat testbed onboard attitude determination method. Through the parabolic flight experiment and data validation with the supporting computer vision system, the Technology Readiness Level of the HDD-RWs was raised from TRL 4 (component and/or breadboard validation in laboratory environment) to TRL 6 (system/subsystem model or prototype demonstration in a relevant environment). HDD-RWs were shown to be a promising alternative to commercial and in-house built CubeSat reaction wheels.