Browsing by Author "Adams, Jim, committee member"

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Open Access
Analysis of a cybersecurity architecture for satellites using model-based systems engineering (MBSE) approaches
(Colorado State University. Libraries, 2025) Johnson, Daniel, author; Bradley, Thomas, advisor; Poturalski, Heidi, committee member; Adams, Jim, committee member; Herber, Daniel, committee member; Reising, Steve, committee member
Historically, satellites have been relatively isolated from cybersecurity threats. However, during the 2020s, cyberattacks on critical ground-based infrastructure became more common and prevalent, and with the increase in technological advancement of peer adversaries, the United States government has come to recognize and define an increasing level of vulnerability in space-based assets as well. This doctoral research seeks to understand and address cybersecurity vulnerabilities inherent in commercial small-scale satellite architectures by demonstrating how model-based systems engineering (MBSE) can enable the design and analysis of a cyber-secure satellite architecture. To determine the cybersecurity vulnerabilities applicable to satellites, a scholarly review of literature on cybersecurity threats and mitigation techniques was performed and applied to satellite systems. The result of this scholarly review is an assessment of the cybersecurity threats applicable to satellites with a particular focus on small satellite architectures, and an understanding of current cybersecurity threat agents and the categories of cyber threats applicable to such satellites. Common architectures and satellite components were analyzed to determine vulnerabilities that could be exploited. The next phase of research then evaluated how industry has applied cybersecurity practices to satellite systems. We were able to determine the gaps which industry currently faces and recommended a set of generic requirements that could help create a cyber-secure satellite from early in the program lifecycle. The final phase of research synthesized the findings from the first two phases to build an MBSE model that integrates cybersecurity engineering and satellite architecture into a singular design process. We also analyzed the benefits to a company of applying the MBSE architectural process, paying particular attention to reusability of the model, cost, and human-centered benefits of committing to MBSE for multiple programs. A finding of this research is that the cybersecurity vulnerabilities for satellites are due to two main factors. First, as technology has advanced and become more available, there is a changing threat landscape where satellites launch is more accessible, increasing the risk that threat actors can compromise unprotected satellites. Second, space technology has lagged behind terrestrial information and cyber technology in its ability to adapt and overcome cybersecurity threats, creating vulnerabilities in satellite architectures. Another revelation is the disconnect between traditional software engineers and their cyber engineer counterparts, leading to a lack of understanding of key cyber-vulnerabilities during the design process. This leads to a consequential need to build cyber-protections into the design process from program initialization. Finally, the cyber tools in use today are also disconnected from the other traditional architectural design tools, leading to our conclusion that all of the tools must be integrated together under an MBSE design process, furthering the evolution of systems engineering while also encouraging the industry to incorporate cybersecurity into satellite programs from the beginning. Upon completion of this research project, the contributions are a scholarly review of the literature on cybersecurity threats and mitigation techniques in space and satellite systems, an evaluation of a set of cybersecurity requirements for satellite systems application, an MBSE example case for a cyber-security embedded satellite system, and an evaluation of the costs and benefits of an MBSE-enabled architecting process as applied to an industrial satellite system architecting process. The combination of this research represents novel contributions to the state of the field by defining the cybersecurity vulnerabilities for Space Systems and exhibiting how MBSE can aid in a cyber-secure architecting process.
Open Access
Development, testing, and validation of a heat transfer model for bi-propellant liquid rocket engines
(Colorado State University. Libraries, 2024) Roberts, Jadon A., author; Windom, Bret, advisor; Wise, Dan, committee member; Adams, Jim, committee member
Accurately modeling the heat transfer characteristics in a bi-propellant liquid rocket engine is a time and resource intensive process. The highly unpredictable and turbulent nature of the combustion requires complex modeling to predict the temperatures and fluid properties. These properties are required to evaluate material requirements and thermal performance. The primary objective of this project was to determine the effectiveness of an adaptable analytical heat transfer model implemented in MATLAB. The analytical model was pursued for the dramatic speed increase over numerical techniques such as computational fluid dynamics (CFD). The effectiveness of the model is determined by comparing results to CFD simulations as well as data obtained from testing. Strong correlations can be drawn with variations a low at 1\% between the CFD and analytical models. Three separate engines were analyzed to gauge the effectiveness of the analytical model across various engine and cooling configurations. A 10 N, 250 N and 2.9 kN thrust engines were developed. Extensive analysis was done on all engines using both the analytical model and CFD. These engines were designed with a wide range of cooling methods including radiative, ablative and regenerative cooling. A test stand previously only capable of testing hybrid rocket engines, was modified to allow for the testing of liquid bi-propellant rocket engines. The needed modifications included the addition of a fuel tank with mass measurement, venting and control valves, and fuel line sensing equipment. Upgrades were completed on the data acquisition system to incorporate additional sensors and controls. Further work was done to improve the safety of the test stand through redundancy and automation. These modifications culminated in two successful static fires of the 2.9 kN engine. The predicted temperatures of the 2.9 kN engine were compared to the test results from the static fires.
Open Access
The application of Agile to large-scale, safety-critical, cyber-physical systems
(Colorado State University. Libraries, 2025) Yeman, Robin, author; Malaiya, Yashwant, advisor; Adams, Jim, committee member; Simske, Steve, committee member; Herber, Daniel, committee member; Arneson, Erin, committee member
The increasing complexity of large-scale, safety-critical cyber-physical (LS/SC/CP) systems, characterized by interconnected physical and computational components that must meet stringent safety and regulatory requirements, presents significant challenges to traditional development approaches. Traditional development approaches, such as the waterfall methodology, often struggle to meet adaptability, speed, and continuous assurance demands. This dissertation explores the feasibility of applying and adapting Agile methodologies to LS/SC/CP systems, focusing on challenges like regulatory compliance and rigorous verification, while intending to prove benefits such as improved risk management and faster development cycles. Through case studies and simulations, this research provides empirical validation of Agile's effectiveness in this domain, contributing a framework for adapting Agile practices to meet the unique demands of LS/SC/CP systems. Employing a mixed-methods approach, the research comprises five key components. First, a systematic literature review (SLR) was conducted to assess the current state of Agile adoption in LS/SC/CP environments. Second, a comparative analysis of the top 10 Agile scaling frameworks was performed to evaluate their suitability for LS/SC/CP system development. Third, a survey of 56 respondents provided both quantitative and qualitative insights into industry trends, adoption patterns, and Agile's impact on LS/SC/CPs. Fourth, 25 one-on-one interviews with industry practitioners further explored the challenges, benefits, and enablers of Agile adoption in these environments. Finally, lifecycle modeling (LML) using Innoslate was utilized to develop a fictional case study, modeling the development of a mid-size low Earth orbit (LEO) satellite using both NASA's Waterfall approach (Phase A-D) and an Agile approach with a series of Minimum Viable Products (MVPs). Findings reveal that Agile methodologies, when adapted for LS/SC/CP systems, enable accelerated development cycles, reducing development time by a factor of 2.5 compared to Waterfall while maintaining safety and regulatory compliance. A key contribution of this study is the introduction of a Continuous Assurance Plugin, which integrates continuous validation within Agile's iterative processes, effectively addressing compliance and safety requirements traditionally managed through phase-gated reviews in Waterfall. Additionally, this research provides: 1. Empirical validation of Agile Scaling Frameworks and their suitability for delivering LS/SC/CP systems. 2. Quantitative and qualitative analysis of Agile's current state and impact in LS/SC/CP environments. 3. Evaluation of key enabling technologies such as Model-Based Systems Engineering (MBSE), Digital Twins, and Continuous Integration/Continuous Deployment (CI/CD) that facilitate Agile adoption for LS/SC/CP systems. This dissertation advances the understanding of Agile's role in LS/SC/CP system development, providing actionable insights and practical adaptations for organizations seeking to implement Agile in complex, safety-critical domains.