Investigating the Novel Challenges Presented by Model Base System Engineering

Traditional document based systems engineering dominates current spacecraft industry practice. Using this approach, many different documents, electronic and otherwise, are used to communicate information about the system under development. Examples of these include specifications, interface control documents, system description documents, trade studies and analysis reports. While this technique historically has been shown to work well while system objectives are clearly defined, consistency, traceability, reusability, and clarity become difficult to maintain when applied to the increasingly complex systems under development today.
Model Based Systems Engineering (MBSE) is a growing alternative to document based methods. Instead of using documents to record system information, MBSE uses a unified and coherent system model. This leads to the exciting possibility of a "single source of truth" for a project that would form the communication platform for all stake holders. By doing so, it avoids inconsistencies in system information commonly experienced with traditional systems engineering, where any change to the design requires updates in several documents in disparate locations. Completeness and communicability are two further benefits reported by literature.
While MBSE adoption is spreading, the spacecraft industry has yet to fully embrace it as standard practice. There have been a number of barriers to further MBSE adoption reported in literature. Firstly MBSE requires a significant change to the way system engineers perform their work, leading to a steep learning curve. Furthermore MBSE has been found to require a higher expenditure of resources early in a project, leading to more risk to the organization undertaking the work. Besides this "false or too high expectations" have been identified as another major source of frustration with MBSE when applied in industry.
This PhD aims to investigate the novel challenges presented by MBSE, with objectives to investigate the following questions:
How can MBSE be used to better perform trade-offs and enhance the decision-making process?
How can expert human knowledge be better fused into the MBSE process?
How can the minimum requirements for useful MBSE models be identified?
What does the early spacecraft design process look like in a real organisation, how can its inefficiencies be minimised by MBSE?
The research falls within the EPSRC engineering theme and will provide systems engineers in the space industry with better ways of working with MBSE.
The PhD is hoped to cover roughly three case studies, with the first one currently underway. Collaborating with Airbus Space and Defence, This case study is focussed on creating a reusable MBSE model structure applicable for low Earth orbiting Earth observation satellites. Following the first objective, it will include the capability to explore design alternatives and perform multi- domain trade-offs.