Assessment of product maintainability for two space domain simulators

The software life-cycle of applications supporting space missions follows a rigorous process in order to ensure the application compliance with all the specified requirements. Ensuring the correct behavior of the application is critical since an error can lead, ultimately, to the loss of a complete space mission. However, it is not only important to ensure the correct behavior of the application but also to achieve good product quality since the applications need to be maintained for several years. Then, the question arises, is a rigorous process enough to guarantee good product maintainability? In this paper we assess the software product maintainability of two simulators used to support space missions. The assessment is done using both a standardized analysis, using the SIG quality model for maintainability, and a customized copyright license analysis. The assessment results revealed several quality problems leading to three lessons. First, rigorous process requirements by themselves do not ensure product quality. Second, quality models can be used not only to pinpoint code problems but also to reveal team issues. Finally, tailored analyses, complementing quality models, are necessary for in-depth investigation of quality.