Systems Engineering

Abstract

AbstractThis chapter provides an overview of the basic principles of the systems engineering discipline and explains its relevance and importance to successfully execute a project in the foreseen time span and allocated budget which meets all its requirements. Whereas the definition of terms and terminology follows the standard of the International Council of Systems Engineering (INCOSE), a comparisons to space tailored standards defined by NASA and ESA is provided. The basic concepts of project planning are introduced, describing the statement of work, statement of compliance, work breakdown structure, and organisational breakdown structure. These are highly relevant tools for the proper definition of the contractual framework of a project that clearly defines the expectations and obligations. The initial project schedule is introduced as an important means to estimate the overall project duration prior to its start. It is then replaced by the working schedule which monitors the actual state and reflects potential delays accrued during the project execution. The early detection of delays and the understanding of the underlying reasons allow the project responsible to take early corrective actions. This helps to recover or at least minimise potential negative implications on the project (e.g., a budget overrun). The precedence diagramming is presented as a method to put the various activities into the required sequence of execution. The identification of the critical path is needed to identify all those work packages that could potentially delay the overall project duration which is demonstrated using the example of a TT&C antenna deployment. The need to identify potential risk factors for a project and to describe and track them in a risk register, is emphasised. The definition of system hierachies allows to decompose a system into subsystems and trace specific functions and requirements to them which simplifies the development, verification, and integration activities. The definition of life cycle stages decomposes a project into different phases that are characterised by a set of mile stones and gates, at which it must be decided whether to proceed from one stage to the next one. The Vee model being one of the most prominent life cycle models in SE is explained in more detail. Whereas plan-driven or waterfall models adhere to a strict sequence of how the life-cycle stages and processes are executed, incremental and iterative development methods are described as an alternative approach that allow to adjust the system design based on intermediate user inputs, before delivering the final product. Furthermore, the main concepts of model based systems engineering (MBSE) and other agile SE methods are outlined. Finally, the need for quality assurance is explained which defines the set of standards used for the specification, development, reviews, and testing in a project.