Technology Readiness Level (TRL)

TRL is NASA's 9-point scale for how mature a technology is, from "we wrote a paper about it" (TRL 1) through "it has flown a real mission" (TRL 9). DoD adopted it. The European Commission adopted it. It is now the lingua franca for talking about how risky a piece of aerospace technology actually is. The scale runs TRL 1 (basic principles observed) through TRL 9 (system flight-proven). The brutal truth: most cool aerospace technology lives at TRL 4 to 6 forever. The valley of death between TRL 6 and TRL 7 is where most defense-tech startups die because nobody funds the gap between demonstration and qualification. When an aerospace leader tells you a technology is "TRL 5," what they usually mean is "we have done it twice in a lab without it catching fire." Translate accordingly. Roles where this matters: Engineering, Program Management, R&D.