Thermal Systems Engineering for Nuclear Electric Propulsion (NEP) High Temperature Radiators

Nuclear Electric Propulsion (NEP) has been considered for crew and cargo class missions to Mars for more than six decades based on fuel efficiencies 10 to 20 times greater than is currently achievable with conventional propulsion. An NEP system is comprised of five technology elements of which the Primary Heat Rejection Subsystem (PHRS) is the largest and most massive element, with a radiative surface area greater than 2,500 m2 and constituting 40-60% of the total NEP dry mass. The Modular Assembled Radiators for NEP Vehicles (MARVL) project seeks to transform the NEP PHRS from a relatively fixed mass element with little margin for improvement into a powerful lever for mass, cost, and development risk reduction by incorporating in-space assembly into the design. To accomplish this the MARVL project is assessing subsystem installation and commissioning configurations as well as designing high temperature radiator units and fluid interfaces compatible with in-space assembly. This presentation provides an overview of the systems engineering products used to inform PHRS design and downselection between in-space assembly options. Subsystem design tools will be presented including internal interface diagrams, induced loads and natural environment specifications, and function flow diagrams which inform the ongoing technical tasks such as analysis and design activities.