Monopropellanttien

Monopropellant is a type of rocket propellant that contains a single active ingredient, which is capable of undergoing a chemical reaction to produce thrust. This reaction is typically an exothermic one, releasing energy in the form of a gas, which is expelled from the rear of the rocket to generate thrust.

The most common monopropellants are hydrazine, unsymmetrical dimethylhydrazine (UDMH), and sulfuric acid-ammonia (or acids based on hydrazine). Hydrazine is often used in its pure form due to its high specific impulse and ability to be burned in a catalyst bed, where it is decomposed into hot gases.

Monopropellant engines are simpler in design compared to bipropellant engines, which require two separate fuels to undergo a chemical reaction. This simplicity leads to increased reliability and lower mass, as fewer components are necessary to produce equivalent performance. However, monopropellant engines are often less efficient due to the energy losses associated with the decomposition reaction.

One of the primary issues with monopropellant engines is the generation of toxic byproducts, such as ammonia and nitrogen. These compounds can be hazardous to the health of those involved in their handling and operation. To mitigate these risks, various safety features and precautions are employed.

The use of monopropellant in spacecraft has been demonstrated in several notable missions, such as those of the European Space Agency's Ariane rocket and NASA's Juno Mission. It continues to be an essential component in the propulsion systems of various satellites and spacecraft.