What is space fuel

Commonly used liquid oxidizers are liquid oxygen, nitrogen tetroxide, etc., and combustion agents consist of liquid hydrogen, metamethylhydrazine, and kerosene. Modern liquid fuel rockets were developed by the American Goddard: the first one used liquid oxygen-kerosene.

The rocket fuel for launching satellites has to be small and light, but the heat emitted has to be large so that the weight of the rocket can be reduced and the satellites can be sent into orbit quickly. Liquid fuel puts out a lot of energy and produces a lot of thrust; moreover, this fuel is easier to control and burns for a longer period of time, so most of the rockets that launch satellites use liquid fuel.

Liquid rocket motors are chemical rocket motors with liquid propellants. The oxidizer and combustant must be stored in separate tanks. Liquid rocket motors generally consist of a thrust chamber, a propellant supply system, and an engine control system. The thrust chamber is an important component that converts the chemical energy of the liquid propellant into propulsive force. It consists of a propellant nozzle, combustion chamber, nozzle assembly, etc. Propellant injected into the combustion chamber through the injector, by atomization, evaporation, mixing and combustion, etc. into a combustion product, with a high speed (25O0 a 5000 m / s) from the nozzle out of the thrust. Combustion chamber pressure up to 2O0 atmospheric pressure (about 20OMPa), the temperature of 300O ~ 400O ℃, so the need for cooling. The function of the propellant supply system is to deliver propellant to the combustion chamber according to the required flow and pressure. According to the different delivery methods, there are two types of supply systems: extruded (pneumatic) and pumped. Extruded supply system is the use of high-pressure gas decompression by the pressure reducer (oxidizer, combustant flow is controlled by the pressure regulator regulator) into the oxidizer, combustant storage tank, will be extruded into the combustion chamber. Squeeze supply system is only used for small thrust engines. High-thrust engines use pump-pressure supply systems, which use hydraulic pumps to deliver propellant. The function of the engine control system is to regulate and control the engine operating program and operating parameters. The working program includes engine starting, working. Shutdown three stages, this process is carried out automatically according to a predetermined program. The working parameters mainly refer to the size of thrust, propellant mixing ratio. The advantages of liquid rocket engines are high specific impulse (25O ~ 5OO seconds), thrust range (single thrust in 1 gram ~ 700 tons of force), can repeatedly start, can control the size of the thrust, longer working time, etc..

Liquid rocket propellant, which is more commonly used: nitrogen tetroxide - hydrazine (meta-dihydrazine, monomethylhydrazine, hydrazine), liquid oxygen - kerosene, liquid hydrogen - liquid oxygen and so on.

Nitrogen tetroxide-hydrazine propellants are widely used and are characterized by their storability and high reliability as nitrogen tetroxide and hydrazine can self-ignite on contact. Nitrogen tetroxide-hydrazine was first used in strategic missiles and later also in launch vehicles for spaceflight.