Chapter 2 - Rocket engine fundamentals

Abstract

Rocket engines operate by expelling a high-temperature gas through a nozzle to produce thrust. This thrust acts to accelerate a spacecraft in the direction opposite that of the expelled gas through the application of Isaac Newton's third law of notion: “For every action, there is an equal and opposite reaction.” In chemical rocket engines, the hot gas is created in a combustion chamber where the propellants are ignited and burned. Nuclear thermal rocket engines, on the other hand, use nuclear reactors to supply the heat needed to raise the propellant to high temperatures. The high-temperature gas exiting the rocket engines is introduced into nozzle assemblies where the thermal energy of the hot propellant gas is converted to kinetic energy in the form of a directed high-speed exhaust flow.