Apollo-type Nuclear Thermal Rockets

The Apollo-type Nuclear Thermal Rockets (called Apollo, or Apollo NTR) is a nuclear thermal rocket propulsion system developed by a Vekllei industrial consortium in the 2030s to commercialise space travel. It is the first closed-system NTR in use, meaning it does not expel radioactive material and is able to be used on the surface of the moon. It is used in the Meteor Starliner SSTOs, and is produced under license in the United States, U.K. and France.

The NSRE chaired the United Nuclear Transport Working Group (NTWG) in the early 2030s, which included state industry partners like General Reactor as well as specialised nuclear energy outfits like Atomic Electric S.p.M., Future Fission and the National Jet Propulsion Laboratory of the ASRE. NTWG conducted a series of experiments with nuclear rocketry in Kala in 2035, and built a technology data base of nuclear thermal reactors that were eventually incorporated into early types of atomic spacecraft (see, for example, the first interplanetary military and research vessel VS-10, a successor to the X-25).

The Commonwealth nuclear thermal reactor project (NTR) was advantaged by the existing use of uranium-233 reactor fuels in civilian infrastructure and the competitive lead of Vekllei domestic material sciences, which lead the world in investment and research. Development of the NTR was based off studies conducted by the U.S. Atomic Energy Commission and the West German Atomic Authority in the decades prior. The crown jewel of Vekllei astronuclear research is the Apollo reactor, used today in the CM-100 series of SSTOs.

The Apollo-type reactor is a gaseous nuclear rocket engine which expels no fissile material. It is an extraordinary device, and stresses materials beyond any other reactor type used in the world today. The reactor core operates at a pressure of over 200 atmospheres and a temperature of 24,000 Kelvin — over four times hotter than the surface of the sun. It represents the pinnacle of Vekllei astronuclear engineering and contributed significantly to the democratisation of Vekllei lunar territories.

The Apollo uses a uranium-233 hexafluoride core, a rare isotope bred from thorium in some types of domestic civilian reactors. The uranium fuels a plasma-phase fission reaction within a transparent quartz-composite bulb that is protected from the incredible heat of the reaction by a vortex of neon laced with silica. The quartz-composite is almost completely transparent to ultraviolet radiation, which passes through the bulb into a hydrogen working fluid, which expands as it heats and is expelled through the rocket nozzle to propel the CM-100 forward.

The Apollo system uses two types of gasses — a neon-silica composite within the quartz envelope to protect the structure of the reactor core, and a hydrogen working fluid enriched with tungsten to increase radiation absorption. It is a relatively simple fission reactor mechanically, but the science of the materials required to operate it (particularly the quartz composite, developed by the Atomic Electric skunkworks) are the product of decades of research invested by the NTWG. Unlike other NTRs, the Apollo does not expel radioactive material and so is able to be used on the lunar surface — a distinct competitive advantage. It is the only closed-system nuclear thermal reactor used on a commercial spacecraft today.