  Software components for on-board architectures in the space domain are
increasingly reliant on Commercial Off-The-Shelf (COTS), Open Source (OSS) or
other third party software products. However, these software components often
have not been built with mission critical requirements in mind. Development
project teams incorporating these products have limited knowledge of or control
over the processes applied during the design, implementation, testing and
maintenance of selected COTS/OSS software products. These constraints generate
uncertainty of potential software induced failures. Moreover, the lack of
information regarding security vulnerabilities increases the risks of their
usage, since their exploitation might lead to undesired behaviour of the
software and therefore to a system failure. The purpose of this paper is to
present a combined approach that takes into account reliability and security
enhancements for third party software, based on Time-Space Partitioning and
Multiple Levels of Security.
