Towards Sustainable Lifecycle Maturity: Integrating Sustainable Development Goals Into the eTRL Framework

The Extended Technology Readiness Level (eTRL) framework extends the classic nine-level TRL model by introducing post-deployment maturity assessments for long-lived systems. While eTRL addresses the evolving alignment of system environment, requirements, and performance after initial deployment, there remains a gap in evaluating sustainability across the operational lifecycle. This paper addresses how sustainability can be incorporated into the eTRL framework by examining practical case studies, including closed-loop life support on the International Space Station and industrial designs like Apple’s ’Liam’ recycling robot. We propose that sustainability be treated as any functional requirement would be considered within the eTRL framework. First, SDGs must be identified on the environmental boundary to capture evolving social, ecological, regulatory, and other forces. Second, sustainability-driven requirements must be formally codified as nonfunctional attributes to ensure resource efficiency, and circular economy principles are integral to system design. Finally, we recommend measuring performance against clearly defined metrics related to the SDGs, facilitating iterative improvements throughout the operating life of the system. By taking a holistic approach and treating SDGs as any other non-functional attribute, we enable the eTRL framework to capture a system’s sustainability objectives. With this systems engineers can more effectively anticipate, measure, and adapt to the long-term implications of design and deployment choices. This expanded perspective offers a pathway for meeting contemporary sustainability challenges while preserving the original strengths of the TRL model in conveying technology readiness.