ADOPTED_FROM:CEN/CLC/TR 17603-11:2021 The present handbook is provided to support the implementation of the requirements of ECSS-E-AS-11 to space projects. With this purpose, this handbook provides guidelines on the w ay to assess the maturity of a technology of a product in a given environment, to use the TRL assessment outcome in the product development framew ork, and to introduce some further refinements for specific disciplines or products to w hich the TRL assessment methodology can be extended. The concept of Manufacturing Readiness Level (MRL) is not addressed in this document, w hilst the concept of TRL can be applied to the technology-related aspects of manufacturing.