Conditional Risk Model Concept for Critical Space Systems Software

Abstract

A software risk assessment approach described, based on the concept of software conditional risk and the ability to define analytically aided, risk-based software test strategies that seek to optimise test coverage. The functional-input space of the software is subdivided into a set of“condition contexts,” corresponding to operating environments and functional conditions for the space system controlled by the software. The formulation of a“conditional risk index,” based on a probabilistic formulation that expresses critical software risk in terms of“condition coverage,” is then enabled with the aid of a combination of logic modelling, automated test vector generation and software defect rate estimation techniques.