Editing Rocket engine (section)

===Propellant===
Rocket propellant is mass that is stored, usually in some form of tank, or within the combustion chamber itself, prior to being ejected from a rocket engine in the form of a fluid jet to produce thrust.

Chemical rocket propellants are the most commonly used. These undergo exothermic chemical reactions  producing a hot jet of gas for propulsion. Alternatively, a chemically inert [[reaction mass]] can be heated by a high-energy power source through a heat exchanger in lieu of a combustion chamber.

[[Solid rocket]] propellants are prepared in a mixture of fuel and oxidising components called ''grain'', and the propellant storage casing effectively becomes the combustion chamber.