Dictionary of Space Concepts

Image

Image NASA. (2000, January). RS-68 being tested at NASA's Stennis Space Center. Retrieved from https://www.nasa.gov/images/content/148709main_d4_testing_08.jpg Photograph of a rocket engine in operation, with a converging plume of hot gas streaming out from the nozzle

Short Definition

A rocket engine is a jet engine that discharges a jet of high-temperature gas as reaction mass, which was acquired from the propellant stored internally in a vehicle. Rocket engines, unlike general jet engines, can only use internally stored propellant to create a jet, because they have to operate in space, where there is no medium like air or water which can be used as a reaction mass in jet engines on Earth.

Detailed Definition

A rocket engine is an internal combustion jet engine that discharges a jet of high-temperature gas as reaction mass, which was acquired from the propellant stored internally in a vehicle. Rocket engines, unlike general jet engines, can only use internally stored propellant to create a jet of gas as a result of chemical reactions, because they have to operate in space, where there is no medium like air or water which can be used as a reaction mass in jet engines on Earth. The nozzle is always an integral part of a rocket engine because it makes the jet accelerate as gas moves through the nozzle, and the higher the speed of a discharged jet, the more efficient the engine. The de Laval nozzle is the most common type of nozzles used in rocket engines, as it accelerates the gas passing through it most efficiently. Gas, when burnt, moves at a low subsonic speed and accelerates as it moves through the nozzle, reaching supersonic speed by the moment it leaves the nozzle.

Etymology

Rocket – from Old Italian rochetto– a bobbinEngine – from Middle English engyn or Anglo-Norman engine or Old French engin– skill, cleverness, war machine

Sample Sentences

The rocket engine ignited with a powerful roar, propelling the spacecraft into space.

Translations from our alliance partners' languages:

References

Braeunig, R. A. (2012). Rocket propulsion. Retrieved from http://www.braeunig.us/space/propuls.htm

Oberth, H. (1972, January). Ways to spaceflight. Retrieved from https://archive.org/details/nasa_techdoc_19720008133/page/n35/mode/2up