Patent Number: 
Section: description

This invention claims the benefit of a provisional patent, Application No. 62/205,242, Filing Date Aug. 14, 2015, by this inventor. Nuclear Energy as motive power for propulsion provides superior performance in terms of bigger payload capacity and much higher speed over conventional chemical or solar-powered rockets. In fact, deep space missions are not economically feasible without nuclear energy. This invention focuses on replacing both chemical and solar-powered rockets with nuclear-powered rockets for deep space journeys. The propulsion section consists of two primary modules: (1) the reactor module, and (2) the propulsion propellant module, also known as the reactor coolant module. It is noted here that the spacecraft propellant is in fact the nuclear reactor coolant, which is a gas. The modules are cone-shaped, and designed in a concentric geometry (i.e., having a common center). They are assembled in sequence in low earth orbit, that is one on-the-top-of the other, as described below. Metaphorically speaking, in a non-scientific description, one might imagine that each module to look like an ice-cream cone. And, the entire propulsion-assembly to look like an ice-cream cone-dispenser, tubular pull-type, without the outer shell or casing. Each module will have locking mechanisms, as well as all the necessary interconnecting utilities, transfer-lines, etc. SMR-P is a very-high-temperature gas-cooled nuclear reactor. The provision for obtaining the nuclear fuel is not included in this effort. The customer is required to purchase the nuclear fuel, per specifications, from authorized sources, or establish own nuclear fuel production capability as permitted by law. The once-through reactor coolant is a gas as it enters the reactor. The reactor has a uranium-235 core, which provides heat from fission reactions. The gas (i.e., the reactor coolant, which is also the spacecraft propellant) passes through the reactor core and is heated to a very high temperature, which then expands through the spacecraft nozzle, and creates the thrust. It is however stored as liquid, during transportation from earth to low earth orbit and assembly at the Low Earth Orbit Propellant Depot—similar to that of conventional chemical rockets. The nuclear fuel consists of High Enriched Uranium, which weighs much less than similar amount of fuel for chemical rockets. The amount of nuclear fuel is mission dependent. The fuel however will be designed such that it will be sufficient for the journey plus reserve. The reactor power is mission specific, and depends on the customer's speed and payload requirements. The nuclear fuel specifications will be provided following the customer's description of the mission, and declaration of speed and payload requirements. A number of gases, such as helium, hydrogen, etc., are envisioned to be used for reactor coolant/the spacecraft propellant, depending on availability, economics, and/or the mission specifics. Additional or spare reactor coolant module(s) may be incorporated into the spacecraft design, for multi-generational journey as the mission evolves. This concept envisions that for a multi-generational journey, the spacecraft is so equipped with: (A) all the necessary provision to scoop and store reactor coolant gases from the atmospheres of en route planets, and/or (B) spare reactor coolant modules. In all cases, the reactor coolant modules are designed to follow the reactor module, in that order, to provide radiation shielding. Other modules, such as instrumentation, electric power, scientific equipment, supplies, and/or crew, will follow the reactor coolant modules, in a similar fashion. It is not the intent of this effort to describe the rest of the spacecraft design. It is sufficed to say that the instrumentation/supplies/equipment/electric power modules, as well as the crew module (if any) will also be carried into low earth orbit and dock with the propulsion section as described below. For spacecraft assembly, all modules, either individually or in combination, will be carried into low earth orbit by conventional chemical rockets, similar to what is being used to carry parts, and supplies to the International Space Station (ISS). Subsequently, the reactor coolant module docks with the reactor module, in a Low Earth Orbit Propellant Depot, in a similar manner as the ISS and supply rockets do. Other modules, such as instrumentation, supplies, electrical power, scientific equipment modules, as well as the crew module (if any), will be assembled in the similar fashion. The purpose of this effort is to delineate the propulsion section of a space-based, nuclear-powered spacecraft, for deep space journeys, which will be assembled and launched from low earth orbit. The spacecraft final assembly consists of modular components delivered to low earth orbit from earth by conventional chemical rockets.