Technology Readiness Levels (TRLs)

A long-term, and ongoing, focus for ESTO and NASA is the appropriate categorization of emerging technologies in terms of their readiness for infusion. NASA maintains the Research and Technology Program and Project Management Requirements, also known as NASA Procedural Requirements (NPR) 7120.8, that include a basic set of TRL definitions in Appendix J. However, in certain technology development cases – such as for information system technologies – more precise categories are deeded to properly circumscribe progress.

The graph below shows where ESTO investments generally fall on the TRL scale, by program area:
Graph shows TRL range for ESTO programs

Hardware TRL Definitions

What follows are the basic TRL definitions for NASA technology development. The full document, including additional descriptions and definitions of terminology, is available as a PDF file.

  • TRL 1 Basic principles observed and reported
  • TRL 2 Technology concept and/or application formulated
  • TRL 3 Analytical and experimental critical function and/or characteristic proof of concept
  • TRL 4 Component/subsystem validation in laboratory environment
  • TRL 5 System/subsystem/component validation in relevant environment
  • TRL 6 System/subsystem model or prototyping demonstration in a relevant end-to-end environment (ground or space)
  • TRL 7 System prototyping demonstration in an operational environment (ground or space)
  • TRL 8 Actual system completed and "mission qualified" through test and demonstration in an operational environment (ground or space)
  • TRL 9 Actual system "mission proven" through successful mission operations (ground or space)

ESTO has also built a worksheet (Microsoft Excel) that aids in performing, and justifying, a TRL assessment.
+ Download the ESTO TRL Worksheet

Software TRL Definitions

What follows are basic TRL definitions with detailed descriptions for information systems technologies.
These definitions are also available as a PDF file.

  • TRL 1 Basic principles observed and reported: Transition from scientific research to applied research. Essential characteristics and behaviors of systems and architectures. Descriptive tools are mathematical formulations or algorithms.
  • TRL 2 Technology concept and/or application formulated: Applied research. Theory and scientific principles are focused on specific application area to define the concept. Characteristics of the application are described. Analytical tools are developed for simulation or analysis of the application.
  • TRL 3 Analytical and experimental critical function and/or characteristic proof-of- concept: Proof of concept validation. Active Research and Development (R&D) is initiated with analytical and laboratory studies. Demonstration of technical feasibility using breadboard or brassboard implementations that are exercised with representative data.
  • TRL 4 Component/subsystem validation in laboratory environment: Standalone prototyping implementation and test. Integration of technology elements. Experiments with full-scale problems or data sets.
  • TRL 5 System/subsystem/component validation in relevant environment: Thorough testing of prototyping in representative environment. Basic technology elements integrated with reasonably realistic supporting elements. Prototyping implementations conform to target environment and interfaces.
  • TRL 6 System/subsystem model or prototyping demonstration in a relevant end-to-end environment (ground or space): Prototyping implementations on full-scale realistic problems. Partially integrated with existing systems. Limited documentation available. Engineering feasibility fully demonstrated in actual system application.
  • TRL 7 System prototyping demonstration in an operational environment (ground or space): System prototyping demonstration in operational environment. System is at or near scale of the operational system, with most functions available for demonstration and test. Well integrated with collateral and ancillary systems. Limited documentation available.
  • TRL 8 Actual system completed and "mission qualified" through test and demonstration in an operational environment (ground or space): End of system development. Fully integrated with operational hardware and software systems. Most user documentation, training documentation, and maintenance documentation completed. All functionality tested in simulated and operational scenarios. Verification and Validation (V&V) completed.
  • TRL 9 Actual system "mission proven" through successful mission operations (ground or space): Fully integrated with operational hardware/software systems. Actual system has been thoroughly demonstrated and tested in its operational environment. All documentation completed. Successful operational experience. Sustaining engineering support in place.

ESTO's Advanced Information Systems Technology (AIST) program is working to further refine TRLs for information systems.