GETTING MORE THRUST

Propellant selection can dramatically affect exhaust gas velocity and, therefore, rocket thrust.

The exit velocity of the propellant is related to the heat of combustion of the fuel and oxidizer or the chemical energy of combustion. Higher chemical energy per unit weight of propellant (fuel + oxidizer) means higher exit velocity per unit weight. There is only one oxidizer-oxygen.

Although it can take many forms, especially in solid rockets, the most efficient form for liquid rockets is liquid oxygen. This means the search for higher chemical energy, which yields higher exhaust velocity, is often limited to the fuel.

Liquid Oxygen
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Florida Space Research Institute ©2002