Nuclear Fission Rocket
|
|
|
|
Nuclear Fission Rocket |
| Nuclear Fission Rocket - Data Panel
Summary: A simple design that is rarely used because of hazardous exhaust. Basic Propulsion: Reaction Specific Impulse: solid core: 500 - 1100 liquid core: 1300 - 1600 gas core: 3000 - 7000 Fuel: Radioactive elements (Uranium and/or Plutonium) Reaction Mass: Usually hydrogen; sometimes water Minimum Technology Required: Middle Tech (Atomic Age Equivalent) Matter Manipulation: Macroscale Controller required: Manual / non-sentient computer First Introduced: Late Information Age. Were used reasonably widely during the early to middle Interplanetary Age Used by: A few vec outposts, some Middle Tech systems. Used in: Low speed interplanetary haulers Construction Costs: Autofac: high (bulky, requires radioactive elements); Hylonano: cheap assuming presence of component materials Running cost: Cheap Advantages: Simple design Disadvantages: Low isp. Interplanetary only. Exhaust radiation deadly to bionts Normal Acceleration: 0.1 to 0.2 g or less Normal Top/Cruising Speed: Up to 10 km/sec Drive Details Fission rockets are thermal rockets that function by heating a working fluid with the thermal output of a nuclear fission reactor. Typically the reaction mass flows directly through solid-core reactors and some liquid-core designs. In the case of gaseous-core fission drives, the heat transfer is by radiation across a transparent, heat resistant ceramic containment vessel. |
The Nuclear fission rocket uses a nuclear reactor to heat liquid hydrogen or some other reaction fluid. There are a number of variant types. The basic and least efficient nuclear fission rocket uses a solid nuclear-reactor core to heat liquid hydrogen which is then ejected as a hot gas. Like the chemical rocket, this is a very low tech form of ship. It is more powerful than a chemical rocket (at least equal thrust but higher isp) and has the advantage over an ion ship of rapid acceleration, although the specific impulse is still too much low for interstellar missions.
Main varieties of fission rocket are the Solid-core rocket, the Liquid-core rocket and its sub-type the NSWR (a Nuclear Salt-Water Rocket using radioactive salts in solution), the Gas-core rocket (and its subtype the closed cycle, so-called Nuclear Lightbulb engine). All of these can be found in use in various medium-tech polities in the Outer Volumes and elsewhere.
The most efficient design is the gas-core type fission rocket. This uses fission of a suitable element in gas form to heat propellant - water or hydrogen, to give an ISP of 3000 to 7000. During the interplanetary and post-nanoswarm period this was used where-ever suitable elements were available (Mercury, Moon, Io); ad was favoured by vecs and radiation adapted clades. Unfortunately the exhaust gas of all fission thermal rocket is highly radioactive due to passage through the nuclear core, and for this reason this engine has never been popular on biont-populated systems, and is even banned in many planetary systems. A few vec outposts and mining factories in the outer volumes use nuclear fission rockets as a cheap low tech solution., and some other radiation-resistant clades also favour this type of rocket as a reliable low tech design
Some exotic fission drives use uranium 235 as reaction mass. The by-products of fission, such as Strontium and Xenon, provide very low thrust with very high efficiency (a specific impulse of up to a million). These exotic drives require advanced technology (usually specially designed nano-pico elements) to control the waste heat and prevent meltdown, direct energized fission fragments, and control the amount of fissionable material in the chamber
