Dictionary of Space Concepts

Image

Image U.S. Air Force. (2010, November). F100 F-15 engine. Retrieved from https://upload.wikimedia.org/wikipedia/commons/6/69/F100_F-15_engine.JPG

Short Definition

A reaction engine is an engine that produces thrust by expelling reaction mass. It works in accordance with the third Newton's law of motion.

Detailed Definition

Reaction engines work in accordance with the third Newton's law of motion, stating that for every action force there is an equal by magnitude, but opposite in direction, reaction force. Thus, reaction engines apply force to the reaction mass, under which reaction mass accelerates and leaves the engine. As a result, the engine together with the vehicle are accelerated by the reaction force that makes the vehicle move. Jet engines and different types of rocket engines are reaction engines. In fact, this is the only engine capable of working in a vacuum, since there is nothing to propel a vehicle besides the fuel (reaction mass) carried by the vehicle itself, which makes those engines the only applicable to spacecrafts. Reaction engines have a broad application area that is not limited to space. For example, boats and ferries are often powered by reaction engines. But instead of a jet of heated gas, they expel water.

Etymology

Reaction – re- (back, again, anew) + action (from French réaction)Engine – from Middle English engyn or Anglo-Norman engine or Old French engin– skill, cleverness, war machine

Sample Sentences

The reaction engine utilized a combination of fuel and oxidizer to generate thrust for propulsion.

Translations from alliance partner languages:

References

The European Space Agency. (2020, December). System study results for SABRE-powered reusable launcher. Retrieved from https://www.esa.int/Enabling_Support/Space_Transportation/Future_space_transportation/System_study_results_for_SABRE-powered_reusable_launcher

Petrescu, R. V., Aversa, R., Apicella, A., Petrescu, F. I. T. (2018, January). Romanian Engineering, "On the Wings of the Wind". Retrieved from https://doi.org/10.3844/jastsp.2018.1.18