Technology readiness levels for the new millennium program

National Aeronautic and Space Administration's (NASA) New Millennium Program (NMP) seeks to advance space exploration by providing an in-space validating mechanism to verify the maturity of promising advanced technologies that cannot be adequately validated with Earth-based testing alone. In meeting this objective, NMP uses NASA Technology Readiness Levels (TRL) as key indicators of technology advancement and assesses development progress against this generalized metric. By providing an opportunity for in-space validation, NMP can mature a suitable advanced technology from TRL 4 (component and/or breadboard validation in laboratory environment) to a TRL 7 (system prototype demonstrated in an Earth-based space environment). Spaceflight technology comprises a myriad of categories, types, and functions, and as each individual technology emerges, a consistent interpretation of its specific state of technological advancement relative to other technologies is problematic. The resulting ambiguity forms an inconsistent basis on which to judge a new technology's RTL. To qualify for consideration by NMP, the technology must have at least achieved TRL 3 (analytical and experimental critical function and/or characteristic proof-of-concept achieved in a laboratory environment). The TRLs used by NMP are the same as those in general use at NASA. The criteria used by NMP to determine when a given TRL is reached are added to their description and are described here. The specific criteria for exit gates have become better defined by as NMP itself has evolved. A brief summary of the NMP history shows how NMP missions have evolved, thus making the consistent interpretation of TRLs increasingly important. The notion of the "relevant environment" is specifically emphasized, wherein relevant environment refers to the environment that adequately stresses the technology in order to provide sufficient confidence in its testing. The TRL of a given technology is based on the environment in which the technology has been tested and validated - beginning in the laboratory, advancing through ever-improving simulation and testing, until finally achieving actual in-space validation. A corollary to what qualifies as a specific technology readiness is the pervasive confusion that exists between what is actually new technology and what is development, which this paper hopes to clarify. An assigned TRL pertains to the status of the technology itself, no to a particular stage in the design and fabrication of a specific item. If new physics elements are being applied or if combined effects from conventional elements create a new function never before experienced, then an item is new technology and the TRL may be very low. However, if the components and subsystems being designed are based on known quantities, and the end product will function within experienced operating ranges that demonstrate effects similar to those of components already flown, then this process is development and the TRL would be fairly high - regardless of the difficulty of producing the product. This is the interpretation of the TRLs that the present NMP flight-validation selections are following.