Evaluation of Recent Upgrades to the NESS (Nuclear Engine System Simulation) Code

The Nuclear Thermal Rocket (NTR) concept is being evaluated a s a potential propulsion technology for exploratory expeditions to the moon , Mars , and beyond . The need for exceptional propulsion syste m performance in these missions has been documented in numerous studies, and was the primary focus of a considerable effort undertaken during the Rover/NERVA program from 1955 to 1973 . The NASA G lenn Research Center is leveraging this past NTR investment i n their vehicle concepts and mission analysis studies with the aid of the Nuclear Engine System Simulation (NESS) code . This paper presents the additional capabilities and upgrades made to this code in order to perform higher fidelity NTR propulsion system analysis and design , and a comparison of its results to the Small Nuclear Rocket Engine (SNRE) design .