Jet propulsion is the action of ejecting mass to generate thrust; therefore, both commercial jets and space-bound rockets use jet propulsion principles to reach their destination. Commercial aircraft use a type of jet propulsion technology called a turbofan engine. The principle of a turbofan engine is to eject a large mass of air at a lower velocity, but with greater fuel-efficiency than turbojet and ramjet engines.Continue Reading
Supersonic aircraft, like fighter jets and supersonic passenger jets, use ramjet engines. These engines create greater velocity by adding heat energy to the air that enters through the forward intake turbines. They are less fuel-efficient because they ignite some of the fuel to heat and accelerate the air as it exits the rear of the engine.
Jet planes cannot travel to outer space because air-intake engines rely on the atmosphere for their primary propellant. Above a certain altitude, the atmosphere is too thin, which provides insufficient mass to generate enough power. Rocket engines solved this problem because they carry all the propellant necessary to generate sufficient thrust. Rocket engines use either solid or liquid fuels that become a gas propellant after they ignite. Older types of rockets contained a combustion chamber and a fuel mixed with an oxidizer. After combustion, the mixture ejected gas through a nozzle with enough velocity to reach outer space.Learn more about Physics