The Extended Technology Readiness Level (eTRL): From Deployment to Obsolescence

The technology readiness level (TRL) has been used for a few decades by National Aeronautics and Space Administration and the Department of Defense to assess the maturity of a technology and evaluate the risks associated with its development. The traditional TRL measure suggests nine levels, from the conception of technology to maturation and deployment. However, the TRL measure is not designed to monitor a system as it matures, ages, and eventually becomes obsolete. There is a critical need for a new measure that captures the performance status and relevance of a system as it ages and eventually becomes a legacy system. This article proposes a novel measure that extends the existing TRL measure, beginning where the traditional TRL stops measuring. The authors propose an extended technology readiness level (eTRL) that measures the contextual relevance of a system and communicates the risks as it ages, faces various environmental, political, and economic changes, or becomes obsolete. The proposed measure takes advantage of set theory to measure the overlaps in requirements, system performance, and system environment to define the eTRL scale from the system's deployment to obsolescence. The eTRL scale will enable stakeholders and program managers to identify and monitor the aging segments within a system and act as a decision analysis tool. The application of the eTRL is demonstrated through a case study of the B52-H airplane, a successful legacy system.