Is Hydrogen peroxide used as rocket fuel ?

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United Launch Alliance Atlas V rocket

Rockets need fuel to push them upward and overcome earth's gravity. These fuels can be of various types. A rocket consists of a reaction engine which is mostly used for the propulsion of spacecraft or even for terrestrial usage such as missiles. The working of rocket engine is mostly based on Newton’s laws.


What are the various types of fuel in rocket engines?

There are various types of rocket engines you come across which are segmented depending upon the type of fuel they use.

  • Hybrid rockets (uses propellant of two different matters)
  • solid fuel rocket (uses solid fuel/oxidizer)
  • spacecraft propulsion (used to provide delta V) and
  • multistage rocket (uses recoil pressure from burning gas) 

What are the properties of hydrogen peroxide?

Hydrogen peroxide or (H2O2) is known to have a very dynamic chemistry as it can function both as an oxidant and also as reductant and that too in both acidic as well as in alkaline solutions. After oxidation the oxygen state is -1 in hydrogen peroxide. Hence it gets oxidized to O2 which is called as zero oxidation state or gets reduced to H2O or OH- which is -2 oxidation of oxygen. Thermodynamically too, hydrogen peroxide is unstable. In chemical terminology, hydrogen peroxide is powerful oxidizing agent and very poor reducing agent. Physically hydrogen peroxide is a very clear non volatile liquid, which is also non inflammable and non explosive and non toxic product. It has appearance like water but has a lot of oxygen.


Can Hydrogen peroxide be used as rocket fuel?

Hydrogen peroxide is known to react with silver but for this it has to be highly concentrated- near about 90%. This is much higher than the hydrogen peroxide sold at the drug store which has concentration of only 3%. The highly concentrated 90% hydrogen peroxide has to be strictly stored in special 5254 aluminum alloy containers having vented caps arranged in shaded ventilated rooms. Hydrogen peroxide with such high concentration can be used as a rocket propellant. Its chemical formula is H2O2. The moment silver and hydrogen peroxide comes in contact, silver starts acting as a catalyst. Due to this reaction the extra oxygen atom is freed producing water as the byproduct. This also creates immense heat. The heat thus produced transforms the water into steam which is used by the engine for ejection at huge speed via rocket nozzle.


Why hydrogen peroxide is called monopropellant?

In a normal rocket engine, two types of chemicals of which one is a fuel and the other an oxidizer are used for propelling the rocket. But hydrogen peroxide is used singly as a fuel and hence called as monopropellant. The rocket engine using it as a fuel is cool as well as very safe and also very easy to throttle.


How does a rocket engine works on hydrogen peroxide?

The rocket engines using hydrogen peroxide as fuel are more steam rockets and this steam is generally created by fierce exothermic reaction of peroxide. When the peroxide passes through a pack of catalyst, it gets decomposed into superheated oxygen and steam. The thrust for propelling is expelled supersonically via DeLaval nozzle and for each amount of injected liquid as the catalyst; 5000 times volume of gas is expelled through the nozzle after the reaction. Catalyst pack is the essential part of such rockets. Pressure tank for holding nitrogen to put pressure on peroxide, stainless steel tank for storing peroxide, flow regulator, lines and gauges, valves and a pressure regulator are other essential elements. The nitrogen helps the passage of peroxide through a flow valve and from here it is injected into the rocket injection plate. The catalyst is composed of several silver screens. These screens transform the liquid peroxide into hot steam and oxygen during the reaction using high pressure. The gas thus produced is used to give power to the vehicle.

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