Nuclear spaceship

Project Prometheus was established in 2003 and included the goal of developing the first reactor-powered spaceship and demonstrating that it can be operated safely and reliably on long duration, deep-space missions for civilian space exploration. NASA s Jet Propulsion Laboratory (JPL) had overall lead for the project. The initial application of space fission power being evaluated was for the Jupiter Icy Moons Orbiter (JIMO), a nuclear electric propulsion spaceship intended to perform deep-space scientific research. 

The Reactor Module includes the primary elements needed to deliver the required electrical power to the rest of the Spaceship. This includes the nuclear reactor, reactor coolant, energy conversion equipment, reactor shield, support structure, and other supporting equipment. The Reactor Instrumentation and Control segment is also part of the Reactor Module, with the sensors physically located in the Reactor Module and the electronics located with the bulk of the other electronics in the Bus Segment of the Spacecraft Module. In accordance Arith Reference 1-10, the design responsibility for all parts of the Reactor Module was assigned to the Naval Reactors Prime Contractor Team (NRPCT) and the approval responsibility is assigned to NR. with the exception of the Aeroshell. 

Space Nuclear Power Plant (SNPP) electric power output could be controlled on reactor outlet temperature and Brayton speed. Mass inventory control (system pressure) was not pursued based on increased complexity and the additional risks to spaceship performance introduced by such a system (e.g., inadvertent coolant addition, additional leak paths). 

The SNPP reactor induced radiations would subject the spacecraft and the l C electrical and electronic components to radiation exposures larger than normally found in terrestrial nuclear applications, but they would be expected to be quite moderate compared to the Jovian radiation levels. In addition, the reactor gamma interactions at the outer surface of the reactor could knock electrons off the surface of the reactor to form an electron cloud that could travel around the shadow shield to the remainder of the spaceship. The existence of this electron radiation had not been confirmed, but needs to be evaluated for reactors which do not have significant amounts of gamma attenuation around the reactor, as would be the case with shadow shields as applied on the JIMO spaceship. 

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