It’s Time to Discontinue Imposing Probability of Success Requirements on Space Systems

Following the early achievements in the U.S. space program, expectations (and demands) for future success became high, and the “achieve big things” mantra was largely replaced with “build reliable systems.” The approach to build reliable systems has been based on a combination of using a standardized set of building blocks and system reliability prediction methods. The demand to build reliable systems is certainly noble, but the aforementioned methods would form a trap that freezes technology to largely 1960s capability with support from a misused methodology that would further penalize any departure from the deemed-reliable building blocks. This article will frame the technical problem and resulting perils of imposing a probability of success requirement on a newly developed space system and provide a basis to discontinue the practice.