This chart depicts a scale of “Technology Readiness Level” or TRL. This TRL depiction is used within the aerospace industry to portray the maturity of the enabling technologies for a proposed system solution.

What “Near-Term” Means

Near-term concepts are those that fit within the definition of the third-best solution. Sir Robert Watson Watt, the British father of radar who, in the 1930s, led the development and installation of the British early warning radars in anticipation of German bomber attacks, defined the “Law of the Third Best.” Watson Watt argued that when responding to critical near-term needs, the “best” solution never comes and the “second best” solution takes too much time; identify the “third best” solution—“the one that can be validated and deployed without unacceptable cost or delay.” (Arthur M. Squires, The Tender Ship: Governmental Management of Technological Change, Birkhäuser, 1986, pp. 122.)

Within the aerospace industry, the third best solution is determined through the use of the Technology Readiness Level (TRL) assessment of the prominent or enabling technologies in a proposed solution.  It is generally accepted that when the enabling technologies of a proposed concept reach a TRL of 6—system/subsystem model or prototype demonstration in a relevant environment (ground or space)—the concept is ready for initiation of program development. As the system advances through the design phase and into production and begins operation, the enabling technologies advance in maturity through TRL 7 (system prototype demonstration in a space environment) and TRL 8 (actual system completed and “flight qualified” through test and demonstration) to TRL 9 (actual system “flight proven” through successful mission operations).

To select specific system configurations for development, the systems engineer will usually emphasize solutions that minimize technology immaturity, as reflected by lower TRL values in the range of 6-8. The systems engineer balances the added cost and time required to employ a TRL 6-8 enabling technology against the need for improved capabilities that cannot be achieved only through the use of TRL 9 technologies.

Hence, a near-term concept is one that uses TRL 6-9 technologies effectively to enable the new capability to be developed and deployed without unacceptable cost or delays. A near-term concept is, thus, one that can enter full scale development. The SLTC focuses on near-term space logistics concepts for improved space access, in-space mobility, and in-space logistics support.