Methodologies for enhancing operability of failure tolerant systems [in International Space Station]

This paper describes a methodology referred to as "channelization" used to ensure a system design meets failure tolerance requirements with a given set of components. In general, channelization is the assignment of one or more failure tolerant system functions to the proper utility resources. This paper provides an expanded view of the methodology by focusing on channelization of functions and their relationships as they relate to mission and operational objectives. A discussion of the benefits derived from channelization is provided along with a discussion of a simple tool used in validating the design. The material conveys experience gained by the Integrated Systems Architecture team that is part of the International Space Station (ISS) program. Examples from ISS are used throughout.