what kind of fuel do space rockets use
Rocket propellant Rocket propellant is a material used by a rocket as, or to produce in a chemical reaction, the reaction mass (propulsive mass) that is ejected, typically with very high speed, from a rocket engine to produce thrust, and thus provide spacecraft propulsion. Each rocket type requires different kind of propellant: chemical rockets require propellants capable of undergoing exothermic chemical reactions, which provide the energy to accelerate the resulting gases through the nozzle. Thermal rockets instead use inert propellants of low molecular weight that are chemically compatible with the heating mechanism at high temperatures, while cold gas thrusters use pressurized, easily stored inert gases. Electric propulsion requires propellants that are easily ionized or made into plasma, and in the extreme case of nuclear pulse propulsion the propellant consists of many small, non-weapon nuclear explosives of which the resulting shock wave of propels the spacecraft away from the explosive, thereby creating propulsion. One such spacecraft was designed (but never built), being dubbed "Project Orion" (not to be confused with the NASA Orion spacecraft).
Solid fuel Wood fuel can refer to several fuels such as firewood, charcoal, wood chips sheets, pellets, and sawdust. The particular form used depends upon factors such as source, quantity, quality and application. In many areas, wood is the most easily available form of fuel, requiring no tools in the case of picking up dead wood, or few tools. Today, burning of wood is the largest use of energy derived from a solid fuel biomass. Wood fuel can be used for cooking and heating, and occasionally for fueling steam engines and steam turbines that generate electricity. Wood may be used indoors in a furnace, stove, or fireplace, or outdoors in a furnace, campfire, or bonfire. As with any fire, burning wood fuel creates numerous by-products, some of which may be useful (heat and steam), and others that are undesirable, irritating or dangerous. There is debate as to whether burning wood can be considered carbon neutral, as technically the wood cannot release more carbon than was sequestered during its growth, although this does not take account of other impacts such as deforestation and rotting has on the carbon footprint.[5] When harvested in a sustainable fashion wood is usually considered to be a renewable solid fuel.[6]