Technology Readiness Levels
FIGURE 3.1.1 Technology readiness level scale. SOURCE: Courtesy of NASA.
NASA employs a technology readiness level (TRL) process to assess the flight readiness of a given technology under development on the basis of its level of maturity (see Appendix D in this report). The TRL is rated on a scale of 1 to 9 depending on the degree of concept development, analytic and empirical validation, and ultimately, flight validation (see Figure 3.1.1).
TRL 9: Actual system “flight proven” through successful mission operations
TRL 8: Actual system completed and “flight qualified” through test and demonstration (ground or space)
TRL 7: System prototype demonstration in a space environment
TRL 6: System/subsystem model or prototype demonstration in a relevant environment (ground or space)
TRL 5: Component and/or breadboard validation in relevant environment
TRL 4: Component and/or breadboard validation in laboratory environment
TRL 3: Analytical and experimental critical formula and/or characteristic proof-of-concept
TRL 2: Technology concept and/or application formulated
TRL 1: Basic principle observed and reported
SOURCE: NASA In-Space Propulsion Web site at http://www.grc.nasa.gov/WWW/InSpace/when.html.