Systems Engineering

A single person may have the time and knowledge to do a preliminary concept or design. A complete space project is usually too complex or would take too long for one person to do. So the Systems Engineering method can be used to help carry out such projects. Aerospace projects, including space systems, are particularly suitable due to their complexity, and were among the main ones for which the method was developed. The method focuses on how projects should be designed and managed over their entire Life Cycle, that being from initial concept to final disposal. Since it applies to the whole project, it is interdisciplinary, connecting tasks performed by Systems Engineering specialists to those of other engineering branches. Key parts of the process include:

• Breaking down a complicated project in such a way that the smallest pieces are simple enough for humans to design.
• Modeling the system so it can be analyzed and optimized, and comparing the actual physical system to the models.
• Control and track the information and design of the pieces and their relationships so the total system will do what you wanted.

Figure 1.5-2 illustrates in general the steps within the Systems Engineering process. The trend is from top to bottom, but we do not show arrows connecting the steps because it is not a strict linear flow. As results are obtained in any task, they can feed back to earlier steps in an iterative fashion, until a stable design solution is reached. So these tasks can happen in parallel, and applied across the different stages of the life cycle. The tasks can also be applied at different levels of detail. They are started at a general level. Once a stable configuration is reached at one level, it then is re-applied at lower levels until detailed design can be done on individual elements. At all levels, there is communication with design specialties, and with outside entities such as the customer, suppliers, and other scientific and engineering organizations. The steps are described in more detail in sections 3 and 4 below and on page 2. It should be noted that an organization capable of designing and building complex space systems is itself a complex system. While it is not often done, Systems Engineering methods can be applied to the organization itself to design and optimize how it functions, or to any complex system of any type, not just space hardware.

The systems engineering process is bounded by natural and human-made constraints. Many of the human constraints are not directly related to design in the way physical properties of materials are. These indirect constraints include economics, laws, and safety of life and property. The process is then also outward-looking, beyond the design itself. Other engineering specialties are more focused on the internal details of the design.