The Nuclear Energy for Rocket Vehicle Application (NERVA) program of the 1960's and early 1970's was dramatically successful,with no major failures during the entire testing program. This successwas due in large part to the successfuldevelopment of a systems engineeringprocess. Systems engineering, properly implemented,involves all aspects of the system design and operation, and leads to optimization of the entire system: cost, schedule, performance, safety, reliability, function, requirements, etc. The process must be incorporatedfrom the very first and continuedto projectcompletion. This paper will discuss major aspectsof the NERVA systemsengineeringeffort, and consider the implicationsfor current nuclear propulsionefforts.