Editing Rocket engine (section)

===Nuclear===
[[Nuclear propulsion]] includes a wide variety of [[spacecraft propulsion|propulsion]] methods that use some form of [[nuclear reaction]] as their primary power source. Various types of nuclear propulsion have been proposed, and some of them tested, for spacecraft applications:

{| class="wikitable"
|-
! Type
! Description
! Advantages
! Disadvantages
|-
! [[Gas core reactor rocket]] (nuclear fission energy)
| Nuclear reaction using a gaseous state fission reactor in intimate contact with propellant
| Very hot propellant, not limited by keeping reactor solid, [[Specific Impulse|''I''<sub>sp</sub>]] between 1,500 and 3,000 seconds but with very high thrust
| Difficulties in heating propellant without losing fissionables in exhaust, massive thermal issues particularly for nozzle/throat region, exhaust almost inherently highly radioactive. Nuclear lightbulb variants can contain fissionables, but cut [[Specific Impulse|''I''<sub>sp</sub>]] in half.
|-
! [[Fission-fragment rocket]] (nuclear fission energy)
| Fission products are directly exhausted to give thrust.
|
| Theoretical only at this point.
|-
! [[Fission sail]] (nuclear fission energy)
| A sail material is coated with fissionable material on one side.
| No moving parts, works in deep space
| Theoretical only at this point.
|-
! [[Nuclear salt-water rocket]] (nuclear fission energy)
| Nuclear salts are held in solution, caused to react at nozzle
| Very high [[Specific Impulse|''I''<sub>sp</sub>]], very high thrust
| Thermal issues in nozzle, propellant could be unstable, highly radioactive exhaust. Theoretical only at this point.
|-
! [[Nuclear pulse propulsion]] (exploding fission/fusion bombs)
| Shaped nuclear bombs are detonated behind vehicle and blast is caught by a 'pusher plate'
| Very high [[Specific Impulse|''I''<sub>sp</sub>]], very high thrust/weight ratio, no show stoppers are known for this technology.
| Never been tested, pusher plate may [[spall|throw off fragments]] due to shock, minimum size for nuclear bombs is still pretty big, expensive at small scales, nuclear treaty issues, fallout when used below Earth's magnetosphere.
|-
! [[Antimatter catalyzed nuclear pulse propulsion]] (fission and/or fusion energy)
| Nuclear pulse propulsion with antimatter assist for smaller bombs
| Smaller sized vehicle might be possible
| Containment of antimatter, production of antimatter in macroscopic quantities is not currently feasible. Theoretical only at this point.
|-
! [[Fusion rocket]] (nuclear fusion energy)
| Fusion is used to heat propellant
| Very high exhaust velocity
| Largely beyond current state of the art.
|-
! [[Antimatter rocket]] (annihilation energy)
| Antimatter annihilation heats propellant
| Extremely energetic, very high theoretical exhaust velocity
| Problems with antimatter production and handling; energy losses in [[neutrino]]s, [[gamma ray]]s, [[muon]]s; thermal issues. Theoretical only at this point.
|}