From TRL to SRL: The Concept of Systems Readiness Levels

Since the 1980’s the National Aeronautics and Space Administration (NASA) has used technology readiness level (TRL) as a means to assess the maturity of a particular technology and a scale to compare technologies. In 1999, the Department of Defense (DoD) embraced a similar TRL concept in their programs. The TRL scale is a measure of maturity of an individual technology, with a view towards operational use in a system context. A more comprehensive set of concerns become relevant when this assessment is abstracted from an individual technology to a system context, which may involve interplay between multiple technologies. We are proposing the concept of a System Readiness Level (SRL) that will incorporate the current TRL scale, and introduce the concept of an integration readiness level (IRL) to dynamically calculate a SRL index. We present the foundations of the SRL and our methodology for developing, validating, and verifying its operational use.