Assessing the Complete Lifecycle of Space Systems Using the Extended Technology Readiness Measure

Space systems are complex, expensive, and challenging to design, develop, and launch, with limited options for servicing, upgrading, and extending their operational life. Decisions regarding their continued use or obsolescence are often subjective, influenced by budgetary or political factors rather than technical criteria. As systems age, performance may degrade, requirements evolve, and environmental factors shift, affecting system sufficiency. There is a need for a formal method to assess aging status and its relevance after space systems are deployed. The Technology Readiness Level (TRL), created in the 1970s, assesses technology maturity pre-deployment but is not designed to to monitor operational lifecycle stages, aging, or retirement. To fill this gap, the authors apply the extended Technology Readiness Level (eTRL), which builds on set theory to track system sufficiency through the intersection of requirements, performance, and environment. Changes in these factors can impact system relevance and lead to obsolescence. The application of eTRL is demonstrated through two case studies: the Hubble Space Telescope, which has exceeded its design life, and the retired NASA Space Shuttle. These examples highlight how the eTRL can effectively evaluate space systems' aging and contextual relevance throughout their operational lifecycles.