Nuclear engine system simulation (NESS) program update

The second phase of development of a Nuclear Thermal Propulsion (NTP) engine system design analysis code has been completed. The standalone, versatile Nuclear Engine System Simulation (NESS) code provides an accurate, detailed assessment of engine system operating performance, weight, and sizes. The critical information is required to support ongoing and future engine system and stage design study efforts. This recent development effort included incorporation of an updated solid‐core nuclear thermal reactor model that yields a reduced core weight and higher fuel power density when compared to a NERVA type reactor. NESS can now analyze expander, gas generator, and bleed cycles, along with multi‐redundant propellant pump feed systems. Performance and weight of efficient multi‐stage axial turbopump can now be determined, in addition to the traditional centrifugal pump.Key code outputs include reactor operating charactertistics and weights and well as engine system parameters such as performance, weights, dimensions, pressures, temperatures, mass flows and turbopump operating characteristics for both design and off‐design operating conditions. Representative NTP engine system designs are also shown. An overview of NESS methodology and capabilities is presented in this paper, with special emphasis being placed on recent code developments.The second phase of development of a Nuclear Thermal Propulsion (NTP) engine system design analysis code has been completed. The standalone, versatile Nuclear Engine System Simulation (NESS) code provides an accurate, detailed assessment of engine system operating performance, weight, and sizes. The critical information is required to support ongoing and future engine system and stage design study efforts. This recent development effort included incorporation of an updated solid‐core nuclear thermal reactor model that yields a reduced core weight and higher fuel power density when compared to a NERVA type reactor. NESS can now analyze expander, gas generator, and bleed cycles, along with multi‐redundant propellant pump feed systems. Performance and weight of efficient multi‐stage axial turbopump can now be determined, in addition to the traditional centrifugal pump.Key code outputs include reactor operating charactertistics and weights and well as engine system parameters such as performance, weights, dim...