10.1 Introduction

Risk is present in every aspect of life. People may face it in the form of a possible car accident as they drive to work on an overcrowded freeway, or a stock-market meltdown threatening the security of their retirement funds. Because risk is multifaceted and ubiquitous, measuring it can take various forms, even within a specific area of technical application, such as that of space-system technology.

Reflecting this variety, risk assessment and modeling have originally developed not as a coherently organized technical discipline but as a collection of techniques and methods devised for specific applications. Some of these methods have become much more widely used and recognized than others. As a result, today it is still much easier to find literature and technical references on particular application techniques than on the subject of risk assessment and modeling as a general discipline applicable to many different fields.

Much of this chapter covers (as it should) some of the risk-assessment techniques most commonly used for space systems. But we also try to offer a general framework and perspective for understanding these techniques and the way they are interrelated. Thus, sections on the background and theoretical fundamentals of risk modeling contain definitions and discussion of basic principles and common features that characterize how we can model and assess risk. These sections also contain introductory-level...