User:WDGraham/Glossary

This is a glossary of rocketry and spaceflight terminology.

A
abort: 1. A launch attempt which is abandoned or postponed after ignition but before commit or liftoff 2. A launch, typically of a manned mission, which is abandoned during ascent, with the spacecraft separating and returning to Earth 3. ? apoapsis: the point of an orbit at which a body is at furtherest from its reference body. apogee: The apoapsis of a geocentric orbit apogee motor: an engine fitted to a spacecraft which is fired at its apogee in order to raise its perigee, or to circularise its orbit. Used mostly to raise satellites from geosynchronous transfer orbit to geosynchronous orbit apohelion: The apoapsis of a heliocentric orbit aposelene: The apoapsis of a selenocentric orbit anomaly: 1. An event or reading outside of expected or normal parameters 2. Euphemism for failure

B
battleship: An inert rocket stage used for ground testing, or to simulate the stage's aerodynamic properties in flight boilerplate: A mockup payload launched either to simulate a vehicle's flight dynamics, or as a payload for a test flight of a rocket bus: A general design to which multiple satellites can be built

C
carrier rocket: A rocket used to launch spacecraft, also known as a launch vehicle clean pad: A launch pad with few or no permanent structures, where the rocket and any support towers are mounted on a mobile launch platform

F
fairing: the nosecone of the rocket, which protects the payload during ascent, also known as a shroud fire: see ignition flight termination: The use of a self-destruct mechanism to destroy a rocket in the event of a malfunction, usually when it could pose a threat to populated areas

I
ignition: The beginning of combustion when an engine is started

L
launch complex: A site consisting of one or more launch pads, plus nearby support and assembly buildings launch pad: The structure from which a rocket is launched launch vehicle: see carrier rocket

M
max-q: The point in a rocket's flight when it is subjected to the greatest dynamic pressure moblile launch platform: A platform upon which a rocket is assembled, moved to a launch pad, and launched mobile launcher: 1. A vehicle which transports, erects and launches a rocket, typically a missile 2. see mobile launch platform

P
payload: 1. The spacecraft that a rocket is carrying, including any upper stages not considered part of the launch system 2. Equipment aboard a spacecraft which is used to complete its mission, but not required for the operation of the spacecraft, such as transponders on a communications satellite or scientific instruments on a research spacecraft. periapsis: the point in an orbit when a body is closest to the reference body perigee: the periapsis of a geocentric orbit perihelion: the periapsis of a heliocentric orbit periselene: the periapsis of a selenocentric orbit

S
satellite: 1. Any object in orbit around a parent object 2. An artificial satellite; spacecraft orbiting a planet, typically one in geocentric orbit 3. A natural satellite; a moon scrub: A launch attempt which is abandoned whilst the countdown is underway. shroud: see fairing space: The area above the majority of the Earth's atmosphere in which spacecraft operate. Defined as beginning at the Kármán line, 100 km above the surface of the Earth stage: A component of a multistage rocket which contains independent fuel tanks and engines, and propels the rocket for part of its ascent stage and a half: A stage which consists of one or more core sustainer engines, and booster engines which feed from the same fuel tanks, but are jettisoned earlier in the flight stage separation: The process of jettisoning a stage which has expended its fuel in order to reduce the mass of the rocket and allow the next stage to burn staging: see stage separation static firing: An engine test conducted on the ground, with the engine or rocket held down to prevent movement strap-on: see booster suborbital: A trajectory whereby a spacecraft enters space, but does not enter orbit, and falls back to earth after reaching apogee sustainer: a core stage which continues to burn after some engines have intentionally separated from it

T
t-zero: The time at which a rocket is scheduled to launch tanking: The fuelling of a rocket or spacecraft before launch terminal countdown: 1. The final stages of the countdown during which controllers are at their stations and making final preparations for launch 2. The last ten seconds of the countdown, which are typically called out by a controller or commentator thrust termination: A system which shuts down a rocket's liquid or hybrid fuelled engines, but without destroying the vehicle, in the event of a malfunction transponder: A device on a satellite used for receiving and relaying communications signals turbopump: A turbine-driven pump used to feed propellant and oxidiser into engines

U
upper stage: 1. The final stage of a carrier rocket, particularly in cases where the vehicle does not require it to reach orbit 2. A additional stage which is considered part of either the rocket or payload, which is used during launch