Technology readiness levels: NASA and Horizon 2020

Technology readiness levels are a nine-level scale for describing how mature a technology is, from level 1, the lowest, to level 9, the highest. In the words of the United States Government Accountability Office (GAO), the scale starts with paper studies of a basic concept and ends with a technology that has proven itself in actual use.

The scale began at NASA, and the European Commission later set out its own wording for its Horizon 2020 research programme. NASA's and Horizon 2020's versions word their levels differently, and the difference matters whenever someone quotes a level.

Where technology readiness levels began

According to GAO's Technology Readiness Assessment Guide, a NASA researcher pioneered the first technology readiness scale in 1974. That scale had seven levels, which were not formally defined until 1989. The same guide also records that the United States defence department (DOD) introduced technology readiness assessments in the 1990s.

The scale now has nine levels, and NASA describes it as a type of measurement system used to assess the maturity of a particular technology. Under NASA's description, each technology project is evaluated against the parameters for each level and then given a rating based on its progress.

NASA's nine technology readiness levels

NASA's current definitions sit in Appendix E of NPR 7123.1D, NASA Systems Engineering Processes and Requirements, effective 5 July 2023. In that appendix's words, the nine levels are as follows.

1. Basic principles observed and reported.
2. Technology concept and/or application formulated.
3. Analytical and experimental proof-of-concept of critical function and/or characteristics.
4. Component and/or breadboard validation in a laboratory environment.
5. Component and/or brassboard validated in a relevant environment.
6. System/sub-system model or prototype demonstration in a relevant environment.
7. System prototype demonstration in an operational environment.
8. Actual system completed and "flight qualified" through test and demonstration.
9. Actual system flight proven through successful mission operations.

Appendix E describes each of the technology readiness levels separately for hardware and for software, and gives each level its success criteria. First, level 1 asks for peer reviewed documentation of the research underlying the proposed concept. Levels 4 to 7 then include documented test performance demonstrating agreement with analytical predictions. Finally, level 9 asks for documented mission operational results.

The hardware descriptions show what the early steps look like in practice. At level 2, invention begins and a practical application emerges, but it remains speculative, with no experimental proof or detailed analysis to support it. NASA's overview of the scale adds that a proof-of-concept model is often constructed during level 3. At level 4, a low fidelity breadboard is then built and operated to demonstrate basic functionality in a laboratory environment.

The appendix also settles which text governs. Where NASA directives conflict on TRL definitions, NPR 7123.1 takes precedence.

The Horizon 2020 levels

The European Commission set out its wording in section G of the General Annexes to the Horizon 2020 Work Programme 2014-2015. Its definitions apply where a topic description refers to a TRL, unless otherwise specified. In Annex G's words, the nine technology readiness levels are as follows.

1. Basic principles observed.
2. Technology concept formulated.
3. Experimental proof of concept.
4. Technology validated in lab.
5. Technology validated in relevant environment (industrially relevant environment in the case of key enabling technologies).
6. Technology demonstrated in relevant environment (industrially relevant environment in the case of key enabling technologies).
7. System prototype demonstration in operational environment.
8. System complete and qualified.
9. Actual system proven in operational environment (competitive manufacturing in the case of key enabling technologies; or in space).

NASA's and Annex G's versions share their shape, but not their words. For example, NASA's level 4 is component and/or breadboard validation in a laboratory environment, while Annex G's level 4 is technology validated in lab. Annex G also adds a note for key enabling technologies at levels 5, 6 and 9.

What a technology readiness assessment does and does not say

GAO's guide describes a technology readiness assessment as a systematic, evidence-based process that evaluates the maturity of critical technologies. Such an assessment looks at a technology at a specific point in time, and it does not eliminate technology risk.

It also does not measure a project's risk level, or assess its ability to achieve cost, schedule or performance goals. In addition, its quality depends on the accuracy and relevance of the test data, analytical reports and other information behind it. The guide also sets out other scales beside technology readiness levels, among them manufacturing, integration and system readiness levels.

Richnovex begins where the client stands: an idea, a prototype or an operating business. Its discovery and strategy phase assesses the current idea, prototype or business state, defines goals and implements the roadmap.

A readiness level names its scale

A technology readiness level, like the assessment behind it, reflects the maturity a technology has shown at one point in time. Because NASA's directive and Horizon 2020's Annex G word their levels differently, a stated level is clearest with its scale named beside it.

Sources

1. NASA, NPR 7123.1D, NASA Systems Engineering Processes and Requirements, Appendix E
2. NASA, Space Communications and Navigation programme, TRL overview
3. European Commission, Horizon 2020 Work Programme 2014-2015, General Annexes, section G
4. United States Government Accountability Office, Technology Readiness Assessment Guide, GAO-20-48G, 2020