Lockheed Martin Space Systems Company, Sunnyvale, California is in the business of designing and engineering satellites for commercial and government customers. This task is by no means a trivial endeavor but Lockheed MartinSunnyvale has many decades of experience in Systems Engineering. Training in systems engineering is a long process whose training tools must be kept up-to-date and appropriate as new advances in technology evolve along-side with the processes that develop these ever-evolving solutions. For many years new systems engineers have been introduced to the Bicycle Model as a paradigm for designing and developing complex systems that are composed of diverse subsystems that interact and function as a whole system. The Bicycle Model originally utilized the idea that a bicycle integrates electrical and mechanical subsystems into a system that provides basic transportation that functions on the input of the operator. This model was relevant back when satellites were merely remote-controlled systems that performed based on input from earth-based operators. Over the decades, much of satellites’ routine operations have migrated from the earth-based operators to onboard computers where routine tasks are encoded in their flight software. With more and more of the satellites’ functionality now being controlled by software, the present Bicycle Model becomes less and less relevant because the model doesn’t address a major component of the satellites’ design; the onboard flight software. It is time to bring the Bicycle Model up-to-date to address the use of software and its implication and considerations in the design of Lockheed Martin’s products. This is the focus of this project; to update the Bicycle Model training exercise to incorporate Electrical, Mechanical and Software interfaces in a complex system.

In recent decades, complexity in aerospace programs has been increasing, leading to large budget and schedule overruns. Many of the risks of complex system development can be attributed to the inadequacy of linear methods when applied to nonlinear domains, i.e., oversimplification in a program amplifies the amount of risk produced when a system behaves unexpectedly. Effectively managing complexity involves responding to the various sources of complexity, whether it appears in the objective behavior of the system itself or in the subjective behavior of the people developing it. Thus, the engineering of complex systems requires nonlinear modeling methods of the system as well as nonlinear processes for developing the system. Much effort tends to be focused on addressing the objective sources of complexity and less is given to understanding and responding to the subjective sources of complexity. This present study examines how facilitating creativity in aerospace system development can serve as a potential strategy for managing complexity. Creativity is a kind of psychological process that integrates linear and nonlinear modes of thinking, and therefore systems engineering processes that reflect the creative process could reduce the risks of complexity. There are three primary results of this work: a novel application of creativity research to aerospace engineering processes; the most comprehensive published review of existing research on creativity in aerospace known to-date; and the proposal of two new systems engineering methods for facilitating creativity to manage complexity. These two new methods designed to improve the Waterfall methodology are as follows: the formation of a Parallel Systems Engineering group that functions analogously to how linear and nonlinear information are coordinated in creativity; and a conceptual model wherein aerospace programs are treated as a series of interdependent creative processes, which can be used to trace the propagation of complexity through various phases of system development.

The research presented provides an overview of a 1U+ form factor propulsion system design developed for the Cal Poly CubeSat Laboratory (CPCL). This design utilizes a Radiofrequency Electrothermal Thruster (RFET) called Pocket Rocket that can generate 9.30 m/s of delta-V with argon, and 20.2 ± 3 m/s of delta-V with xenon. Due to the demand for advanced mission capabilities in the CubeSat form factor, a need for micro-propulsion systems that can generate between 1 – 1500 m/s of delta-V are necessary. By 2019, Pocket Rocket had been developed to a Technology Readiness Level (TRL) of 5 and ground tested in a 1U CubeSat form factor that incorporated propellant storage, pressure regulation, RF power and thruster control, as well as two Pocket Rocket thrusters under vacuum, and showcased a thrust of 2.4 mN at a required 10 Wdc of power with Argon propellant. The design focused on ground testing of the thruster and did not incorporate all necessary components for operation of the thruster. Therefore in 2020, a 1U+ Propulsion Module that incorporates Pocket Rocket, the RF amplification PCB, a propellant tank, propellant regulation and delivery, as well as a DC-RF conversion with a PIB, that are all attached to a 2U customer CubeSat for a 3U+ overall form factor. This design was created to increase the TRL level of Pocket Rocket from 5 to 8 by demonstrating drag compensation in a 400 km orbit with a delta-V of 20 ± 3 m/s in the flight configuration. The 1U+ Propulsion Module design included interface and requirements definition, assembly instructions, Concept of Operations (ConOps), as well as structural and thermal analysis of the system. The 1U+ design enhances the capabilities of Pocket Rocket in a 1U+ form factor propulsion system and increases future mission capabilities as well as propulsion system heritage for the CPCL.

This thesis examines the feasibility of substituting the system input script of Cal Poly’s Horizon Simulation Framework (HSF) with a Model Based Systems Engineering (MBSE) model designed with the Systems Modeling Language (SysML). A concurrent student project, SysML Output Interface Creation for the Horizon Simulation Framework, focused on design of the HSF Translator Plugin which converts SysML models to an HSF specific XML format. A SysML model of the HSF test case, Aeolus, was designed. The original Aeolus HSF input script and the translated SysML input script retained the format and dependency structure required by HSF. Both input scripts returned identical results and thus validated the feasibility of linking SysML with HSF through the HSF Translator Plugin. A second SysML model of the Cal Poly CubeSat mission, ExoCube, was also designed and converted into an HSF input script. The ExoCube input script also retained the format and dependency structure required by HSF. This demonstrated that future SysML models can be used in conjunction with the HSF Translator Plugin to create a functional HSF system input script.

With the rise of CubeSats and the demonstration of their many space applications, there is interest in interplanetary CubeSats to act for example as scientific investigations or communications relays. In line with the increasing demand for this class of small satellites, the Cal Poly CubeSat Lab (CPCL) seeks to develop a bus that could support an interplanetary science payload. To facilitate this, a mission concept to conduct science of the moons of Mars, Phobos and Deimos, is investigated by determining the mission needs for a CubeSat in a Phobos-Deimos cycler orbit through the development of a baseline design to meet mission objectives. This baseline design is then compared by subsystem to CPCL’s current capabilities to identify technology, facility, and knowledge gaps and recommend a path forward to close them. The resulting baseline design is a 16U bus capable of transferring from an initial low Mars orbit to a Phobos-Deimos cycler orbit using a combined chemical and electric propulsion system. The bus is designed for a 3.5 year mission lifetime collecting radiation data and images, utilizing a relay architecture to downlink payload data. Estimates for mass, volume, and power available for an additional payload are up to 2.3 kg in ~4U with power consumption up to 13 to 38 W. This baseline requires further iteration due to non-closure of the thermal protection subsystem and improvement of other subsystems but serves as a starting point for exploration into CPCL’s next steps in becoming an interplanetary bus provider. Major subsystem areas identified for hardware performance improvement within CPCL are propulsion, communications, power, and mechanisms.

Spacecraft operating on the Martian surface have used relay satellites as a means of improving communication capabilities, mainly in terms of bandwidth and availability. However, the spacecraft used to achieve this have been large spacecraft (1000s of kilograms) and were not designed with relay capability as the design priority. This thesis explores the possibility of using a CubeSat-based constellation as a communications network for spacecraft operating on the Martian surface. Brute-force techniques are employed to explore the design space of possible constellations. An analysis of constellation configurations that provide complete, continuous coverage of the Martian surface is presented. The stability of these constellations are analyzed, and recommendations are made for stable configurations and the orbital maintenance thereof. Link budget analysis is used to determine the communications capability of each constellation, and recommendations are made for sizing each communication element. The results of these three analyses are synthesized to create an architecture generation tool. This tool is used to identify mission architectures that suit a variety of mission requirements, and these architectures are presented. The primary recommended architecture utilizes 18 CubeSats in three orbital planes with six additional larger relay satellites to provide an average of over one terabit/sol downlink and 100 kbps uplink capability.

As the demand for air transportation is projected to increase, the environmental impacts produced by air travel will also increase. In order to counter the environmental impacts while also meeting the demand for air travel, there are goals and research initiatives that aim to develop more efficient aircraft. An emerging technology that supports these goals is the application of hybrid propulsion to aircraft, but there is a challenge in effectively exploring the performance of hybrid aircraft due to the time and money required for safe flight testing and due to the diverse design space of hybrid architectures and components. Therefore, computational tools that are capable of simulating the performance of a hybrid aircraft are incredibly useful in the design process and research space. Existing work on the simulation of hybrid aircraft focuses on modelling a specific hybrid propulsion system in a particular airframe, but it would be desirable to have a simulation tool that is not specific to one design. In this thesis, a simulation framework that can be easily configured for different types of hybrid structures and components is presented, and the simulator is validated using flight test data which demonstrates that the performance of the simulated aircraft is representative of a real aircraft. A design for a hybrid aircraft is also modelled and simulated over different flight profiles in order to study the performance of the hybrid propulsion system. Results indicate that the hybrid aircraft can be successfully simulated and demonstrate how the simulator can be used as a tool to study the best way to fly and operate a hybrid aircraft.

This thesis is the product of an effort to develop a CubeSat Conceptual Design Tool for the California Polytechnic State University CubeSat Laboratory. Such a tool is necessary due to inefficiencies with the current conceptual design process. It is being developed to increase accessibility, reduce design time, and promote good systems engineering within CubeSat development. The development of the architecture of a conceptual design tool, the core user-interface element, and the completion of a module for the electrical power subsystem is the focus of this thesis. The architecture is built around different modules to design different subsystems that work in conjunction. The module in the tool was developed to allow a user to size an electrical power subsystem, and that is the basis for future subsystem development. Model-based Systems Engineering was also utilized as an endpoint for the tool’s outputs, and a CubeSat Model has been built for this effort. Validation has been successful on the Conceptual Design Tool as implemented at this time, so the tool it is ready to design CubeSat electrical power subsystems and be expanded upon by other tool developers.

This graduate project compares legacy simplified general perturbation model (SGP4) code developed by NASA Johnson Space Center, Orbital Debris Program Office, to a recent public release of SGP4 code by David Vallado. The legacy code is a subroutine in a larger program named PREDICT, which is used to predict the location of orbital debris in GEO. Direct comparison of the codes showed that the new code yields better results for GEO objects, which are more accurate by orders of magnitude (error in meters rather than kilometers). The public release of SGP4 also provides effective results for LEO and MEO objects on a short time scale. The public release code was debugged and modified to provide instant functionality to the Orbital Debris Program Office. Code is provided in an appendix to this paper along with an accompanying CD. A User’s Guide is presented in Chapter 7.

The Horizon Simulation Framework, or HSF, is a modeling and simulation framework compiled from C/C++ source code into a command line program. Picasso is an interface designed to control the input files to Horizon by providing visual tools to create and manipulate the XML files used to define an HSF system of assets, their environment, and other simulation parameters. Picasso also supports the visualization of Horizon output in several different forms, and import mechanics from online space object catalogues.