Aviation & Aerospace

The specific models, classifications, and structural designs of vehicles that fly in the atmosphere and beyond.

• Aerialalso airborne
  Relating to operations, equipment, or vehicles that function in the air.
• Airbus
  A major European aerospace corporation that designs and manufactures commercial aircraft.
• Airshipalso dirigible
  A powered, steerable aircraft that relies on lighter-than-air gas for lift.
• Alien reproduction vehiclealso ARV
  A theoretical human-made craft reverse-engineered from captured extraterrestrial technology. Shop talk
• Anhedral
  The downward angle of an aircraft's wings relative to the horizontal plane.
• Area rulealso Whitcomb area rule
  An aerodynamic design concept that reduces drag at transonic and supersonic speeds.
• Atlas
  A historic American intercontinental ballistic missile that evolved into a highly successful family of space launch vehicles.
• Blimpalso non-rigid airship
  A lighter-than-air craft that relies entirely on internal gas pressure to maintain its shape.
• Boilerplatealso mass simulator
  A non-functional spacecraft mockup used to test launch vehicles, recovery systems, and ground handling.
• Cabin
  The pressurized section of an aircraft fuselage where passengers and crew sit.
• Canuck
  The nickname for the Avro Canada CF-100 fighter-interceptor. Shop talk
• Capsule
  A pressurized spacecraft module designed to carry a crew and return them to Earth safely.
• Centre of liftalso center of pressure
  The theoretical point on an airframe where the sum total of all aerodynamic lifting forces acts.
• CEOalso Current Engine Option
  Current Engine Option is a designation used by Airbus to identify original engine configurations.
• Clean
  An aircraft configuration where all retractable gear, flaps, and external stores are stowed or removed to minimize drag.
• CM
  The command module is the main control and habitation section of a spacecraft.
• Compound balloonalso Rozière balloon
  An aerostat that uses two different lifting gases in separate envelopes to achieve buoyancy.
• Constellationalso satellite constellation
  A coordinated group of artificial satellites working together to provide continuous global coverage.
• Cricket
  A repetitive, high-pitched electronic chime used to alert pilots to a specific failure. Shop talk
• CSM
  The Command and Service Module was the primary spacecraft used during the Apollo lunar program.
• Cycleralso cycler trajectory, Aldrin cycler
  A spacecraft placed in a permanent, looping trajectory between two massive bodies like Earth and Mars.
• Delta wing
  An aircraft planform shaped like an isosceles triangle.
• Demisability
  The ability of a spacecraft or satellite component to burn up completely during atmospheric reentry.
• Demisable
  Designed to completely vaporize from friction heat during atmospheric reentry.
• Dihedralalso dihedral angle
  The upward angle of an aircraft's wings relative to the horizontal plane.
• DVCS
  A direct view camera system is an optical or digital system used to provide pilots or operators with a direct visual feed.
• ERV
  Earth Return Vehicle, a spacecraft designed to bring crew or samples back to Earth.
• Fleet leader
  The specific aircraft or component in a fleet with the highest number of flight hours or cycles.
• Free-fall time
  The time it takes for a body to collapse under its own gravity with no opposing forces.
• FTA
  Flight test article is an aerospace vehicle or component built specifically for testing.
• Gunship
  A heavily armed aircraft or helicopter designed to provide close air support and attack ground targets.
• Gyrocopteralso autogyro, gyroplane
  A rotorcraft that uses an unpowered rotor in autorotation to develop lift and an engine-driven propeller for thrust.
• Heavy
  An aircraft capable of a maximum takeoff weight of 300,000 pounds or more.
• Helicopteralso chopper, helo
  A rotorcraft that generates lift and thrust from engine-driven overhead rotors.
• Homebuildalso homebuilt, amateur-built aircraft
  An aircraft constructed by an amateur builder rather than a certified factory. Shop talk
• Hubble
  A Hubble is a large space telescope or reconnaissance satellite utilizing a massive primary mirror. Shop talk
• Interstage
  The structural ring or cylinder that connects two stages of a multi-stage rocket.
• ISS
  An abbreviation for International Space Station, the largest modular laboratory in low Earth orbit.
• IXV
  An abbreviation for Intermediate eXperimental Vehicle, a European lifting body demonstrator.
• JCA
  An abbreviation for Joint Combat Aircraft, a military procurement designation for multirole fighters.
• Launch vehicle
  A rocket or other system used to carry a payload from the Earth's surface into space.
• Lawalso flight control law
  A specific software mode that governs how a fly-by-wire aircraft responds to pilot inputs.
• LCV
  A light combat vehicle used for rapid deployment and tactical operations.
• LEMalso Lunar Module
  The Lunar Excursion Module was the lander portion of the Apollo spacecraft.
• LMalso Lunar Module, LEM
  The Lunar Module was the lander used by the Apollo program to reach the surface of the Moon.
• LUCAS
  A low-cost uncrewed combat attack system is an expendable or attritable military drone.
• LVW
  The landing vehicle, wheeled is an amphibious military transport.
• Mars rover
  A Mars rover is an automated motor vehicle designed to travel across the surface of Mars.
• Microsatellitealso microsat
  A small artificial satellite typically weighing between 10 and 100 kilograms.
• Minisatellite
  A satellite with a wet mass between 100 and 500 kilograms.
• MMOD
  Micrometeoroid and orbital debris, the collective hazard of tiny, high-speed objects in space.
• Multistagealso staged
  A multistage vehicle uses two or more distinct rocket sections that fire and discard sequentially.
• Narrowbodyalso single-aisle aircraft
  A narrowbody is a commercial airliner with a single passenger aisle.
• NF
  A military aircraft designation prefix indicating a fighter permanently modified for flight research.
• NGSTalso New Generation Space Telescope
  The New Generation Space Telescope was the early development name for the James Webb Space Telescope.
• OH
  The military designation for an observation helicopter.
• OV
  An Orbiter Vehicle is the primary crewed spacecraft component of a reusable launch system.
• Paper airplanealso paper plane, vaporware
  An aircraft concept or design that exists only in blueprints and proposals. Shop talk
• Parasitealso parasite aircraft, parasite fighter
  A smaller aircraft designed to be carried aloft and launched by a larger mother ship.
• PMV
  A protected mobility vehicle is a light armored truck often transported by military cargo aircraft.
• Polyhedral
  A polyhedral wing design features multiple changes in the upward angle of the wingspan.
• PT
  A Patrol Trainer is an aircraft configured to teach crews how to operate maritime patrol and reconnaissance missions.
• Puddle jumperalso commuter plane, regional prop
  A small, light aircraft used for short-haul flights between regional airports. Shop talk
• Pusheralso pusher prop
  An aircraft configuration where the propeller is mounted behind the engine.
• QCalso Quick Change
  Quick Change, an aircraft designed to be rapidly converted between passenger and cargo layouts.
• Radar cross sectionalso RCS, radar signature
  A measure of how detectable an aircraft or object is to radar systems.
• Reentrant
  Designed to survive a return through a planetary atmosphere.
• Rigidalso rigid airship
  A type of airship that maintains its shape using an internal structural framework.
• RLV
  A reusable launch vehicle designed to return to Earth intact and fly multiple missions.
• Roundelalso Cockade
  A circular painted insignia used on military aircraft to identify their national air force.
• Rozière balloon
  A hybrid balloon that combines a lifting gas cell with a hot air envelope.
• Safe modealso safing
  An autonomous emergency state triggered by a spacecraft when it detects a critical fault.
• Sailcraftalso solar sailcraft
  A spacecraft that uses radiation pressure acting on large reflective sails for propulsion.
• Sandyalso Spad
  A radio callsign and nickname for the Douglas A-1 Skyraider during the Vietnam War. Shop talk
• SCA
  The Shuttle Carrier Aircraft used by NASA to transport the Space Shuttle orbiter.
• Schwalbealso Me 262
  The German nickname for the Messerschmitt Me 262, the world's first operational jet fighter. Shop talk
• Scooperalso skimmer, superscooper
  An amphibious firefighting aircraft that skims lakes or oceans to fill its water tanks. Shop talk
• Sears-Haack body
  An aerodynamic shape mathematically optimized to produce the lowest possible wave drag at supersonic speeds.
• SEATalso single-engine air tanker
  A single-engine air tanker is a small aircraft modified to drop water or fire retardant.
• Skyhookalso momentum-exchange tether
  A theoretical space transportation system using a long, orbiting tether to catch and lift payloads into orbit.
• SLS
  The Space Launch System is a super heavy-lift expendable launch vehicle developed by NASA.
• SLV
  A space launch vehicle is a rocket designed to carry payloads from the Earth's surface into space.
• Sounding rocketalso research rocket
  A suborbital rocket designed to carry scientific instruments into the upper atmosphere.
• Space-based
  Located in orbit or operating from outer space rather than on the ground.
• Space probealso probe
  An uncrewed robotic spacecraft sent to explore deep space.
• Spacecraftalso vehicle
  Any vehicle designed to fly and operate in outer space.
• Spaceshipalso crewed spacecraft, manned spacecraft
  A crewed vehicle designed to operate and sustain human life in outer space. Shop talk
• sRLV
  A suborbital reusable launch vehicle designed to cross the edge of space and return intact.
• SSTO
  A single-stage-to-orbit vehicle that reaches space without dropping hardware.
• Starfighteralso F-104, Widowmaker
  A supersonic interceptor aircraft known for its extremely thin wings and high speed.
• Stealthalso low-observable
  Design techniques and materials used to make an aircraft or vessel nearly invisible to radar and thermal detection.
• Subsatellite
  A smaller secondary spacecraft deployed from a primary satellite or space probe after it reaches orbit.
• Trial balloonalso pilot balloon, pibal
  A small uncrewed balloon released to measure upper-level wind conditions.
• TSTO
  Two-stage-to-orbit refers to a launch vehicle that uses two distinct propulsion stages to reach space.
• UCASalso UCAV
  An uncrewed combat aerial system is an autonomous or remotely piloted aircraft network designed for strike missions.
• UCAV
  An Unmanned Combat Aerial Vehicle is a weaponized drone designed for strike missions.
• Upmass
  The total weight of payload and supplies a launch vehicle can deliver into space.
• VC
  The military designation prefix for an aircraft modified to transport very important persons.
• VTHL
  Vertical takeoff and horizontal landing describes a vehicle that launches straight up but lands on a runway.
• VTOL
  Vertical takeoff and landing refers to aircraft that can hover, take off, and land straight down.
• VTVL
  This acronym describes a vehicle that lifts off straight up and returns to the ground in the same upright orientation.
• Waterbomberalso airtanker, firebomber
  A fixed-wing aircraft or helicopter designed to drop large payloads of water or fire retardant on wildfires.
• Widebodied
  Describing an aircraft with a fuselage wide enough for twin passenger aisles.
• Widebodyalso wide-body
  A commercial airliner with twin aisles and a high passenger capacity.
• YC
  The US military designation prefix for a prototype cargo aircraft.
• Zeppelinalso rigid airship
  A type of large rigid airship supported by an internal metal framework.

The individual mechanical, electronic, and structural pieces that make up an airframe or orbital vehicle.

• Advance angle
  The fixed mechanical offset between a helicopter rotor blade's pitch horn and the swashplate.
• Airbrakealso speedbrake
  A deployable flight control surface designed to increase aerodynamic drag.
• Airspeed indicatoralso ASI
  A flight instrument that displays the aircraft's speed relative to the surrounding air.
• Alpha hingealso lead-lag hinge, drag hinge
  A mechanical joint in a helicopter rotor hub that allows the blade to move back and forth in the plane of rotation.
• Artificial horizonalso attitude indicator, ADI
  A primary flight instrument that shows the aircraft's pitch and roll relative to the earth's horizon.
• Astrionics
  The specialized field of electronics designed for use in spacecraft and the space environment.
• Avionicsalso Avionic
  The electronic systems used on aircraft, artificial satellites, and spacecraft.
• Black boxalso flight recorder, FDR
  The heavily armored flight data and cockpit voice recorders used in aircraft. Shop talk
• Blucket
  A specialized engine blade that functions as both a turbine bucket and a compressor fan.
• Bugalso heading bug, speed bug
  A small movable marker on the rim of a flight instrument dial.
• CAMalso cockpit area microphone
  The cockpit area microphone is an audio sensor that records ambient sounds on the flight deck.
• Canardalso foreplane
  A small horizontal lifting surface mounted near the nose of an aircraft ahead of the main wing.
• Cannulaalso nasal cannula, oxysaver
  A lightweight plastic tube with two prongs that delivers supplemental oxygen into the nostrils.
• Chin
  The lower forward section of an aircraft fuselage, situated directly beneath the nose.
• Cloche
  An early type of aircraft control column featuring a bell-shaped base.
• Control surface
  A movable aerodynamic flap or panel used to steer and stabilize an aircraft in flight.
• Cyclicalso cyclic stick, cyclic pitch control
  A helicopter control stick that changes the pitch of the main rotor blades to direct horizontal movement.
• Delta hingealso flapping hinge
  A mechanical joint in a rotor hub that allows blades to flap up and down.
• Depthalso camber depth
  The maximum perpendicular distance from the chord line to the cambered surface of an airfoil.
• DET
  A digital event timer used on flight decks to track mission elapsed time or specific countdowns.
• Dope
  A specialized lacquer applied to fabric-covered aircraft to shrink, waterproof, and stiffen the material.
• Drag parachutealso drag chute, drogue chute
  A parachute deployed from the tail of an aircraft or spacecraft to provide aerodynamic braking.
• Droopalso droop leading edge, droop snoot
  A hinged section on the leading edge of a wing that tilts downward to increase lift at low speeds.
• Ejectable
  An ejectable is any hardware component designed to be deliberately cast off from a spacecraft or aircraft during operation.
• Elevator
  An elevator is a hinged control surface on the tail of an aircraft that controls pitch.
• Elevon
  An elevon is a combined control surface that handles both pitch and roll on tailless aircraft.
• ELSSalso PLSS
  An extravehicular life support system is the portable equipment that keeps an astronaut alive during a spacewalk.
• Erect
  To spin up and align a gyroscopic flight instrument to its proper reference plane.
• Fairey-Youngman flap
  The Fairey-Youngman flap is an aircraft wing flap that drops down and moves aft before rotating.
• Featherable
  A featherable propeller can rotate its blades parallel to the airflow to reduce drag when the engine stops.
• Flap
  A hinged surface on the trailing edge of an aircraft wing used to increase lift and drag.
• Foilalso airfoil, aerofoil
  A clipped term for an airfoil, a curved surface designed to generate lift. Shop talk
• Fowler flap
  A type of wing flap that slides backward before hinging downward.
• FTSalso AFTS
  A flight termination system destroys a rocket or missile if it deviates from its planned trajectory.
• Fuselage
  The fuselage is the main central body of an aircraft that holds the crew, passengers, and cargo.
• Ground proximity warning systemalso GPWS, EGPWS
  An avionics system designed to alert pilots if their aircraft is in immediate danger of flying into the ground.
• Hazcam
  Hazard avoidance cameras mounted on planetary rovers.
• Heatshieldalso heat shield
  A thermal protection system for vehicles entering an atmosphere.
• High-time
  A high-time component or aircraft has accumulated a large number of flight hours or operating cycles. Shop talk
• HIV
  A safety mechanism used to shut off fluid flow to a specific hydraulic circuit.
• Honeycomb
  A lightweight core material made of hollow hexagonal cells sandwiched between face sheets.
• Instrumentalso flight instrument
  A device in the cockpit that displays critical flight data to the pilot.
• IRalso IRS, inertial reference system
  An inertial reference system uses gyroscopes and accelerometers to determine an aircraft's position and attitude.
• IRS
  An abbreviation for inertial reference system, the onboard hardware that tracks aircraft movement using internal sensors.
• Krueger flap
  A hinged lift-enhancement device mounted on the lower surface of an aircraft wing's leading edge.
• Leading edge
  The forward-facing contour of an airfoil that first meets the oncoming air.
• LESalso launch escape system, launch abort system
  The Launch Escape System is a safety mechanism designed to pull a crew capsule away from a failing rocket.
• Lifealso life out, time out
  To track or expire a component based on its accumulated flight hours or cycles. Shop talk
• LORRI
  The Long-Range Reconnaissance Imager is a telescopic camera used on deep space probes.
• MAHLI
  The Mars Hand Lens Imager is a high-resolution camera mounted on the robotic arm of the Curiosity rover.
• Mainsparalso main spar
  The mainspar is the primary structural member of an aircraft wing that carries flight loads.
• MARDI
  The Mars Descent Imager is a downward-facing camera on the Curiosity rover used during its landing sequence.
• MastCam
  A multispectral imaging system mounted on the elevated structure of a planetary rover.
• MRO
  Maintenance, repair, and overhaul, the industry dedicated to keeping aircraft airworthy.
• Navcamalso navigation camera
  A navigation camera is an engineering camera used by rovers to plan movements and avoid obstacles.
• NDalso navigation display
  The navigation display is a digital screen showing an aircraft's route, weather, and traffic.
• Nose capalso radome, nose cone
  The forward-most structural cover of an aircraft or spacecraft.
• Oleoalso oleo strut, shock strut
  A pneumatic-hydraulic shock absorber used on aircraft landing gear.
• Parachutealso chute
  A fabric canopy deployed to create aerodynamic drag and slow a falling object.
• PCRalso pitch link
  A pitch control rod is a mechanical linkage that adjusts the blade angle on a helicopter rotor.
• PFS
  The Planetary Fourier Spectrometer is an infrared instrument used on spacecraft to analyze planetary atmospheres.
• POS
  A position and orientation system is an integrated sensor suite that tracks an aircraft's exact location and attitude.
• Probealso refueling probe
  A rigid tubular boom extended from an aircraft to receive fuel during midair refueling.
• PTTalso part task trainer
  A specialized training device used to teach specific aircraft systems or procedures.
• REMS
  The Rover Environmental Monitoring Station, a weather instrument suite on the Curiosity Mars rover.
• RHU
  A radioisotope heater unit, a small device that uses radioactive decay to keep spacecraft components warm.
• Rootalso wing root
  The innermost section of an aircraft wing or rotor blade where it attaches to the fuselage or hub.
• SAS
  The stability augmentation system that automatically dampens unwanted aircraft motions.
• Section
  A structural slice or sub-assembly of an aircraft fuselage.
• Shipset
  A complete package of matching components required to build or outfit a single aircraft.
• Ski
  A long, flat runner attached to the landing gear of an aircraft for operating on snow or ice.
• Skirt fingeralso finger
  A flexible, replaceable segment attached to the lower edge of a hovercraft's main skirt.
• Slatalso leading-edge slat
  An aerodynamic surface on the leading edge of a wing that extends to increase lift at low speeds.
• Stab
  The horizontal or vertical stabilizer on the tail of an aircraft. Shop talk
• Staggeralso positive stagger, negative stagger
  The longitudinal offset between the upper and lower wings of a biplane or triplane.
• Tail cone
  The aerodynamic fairing at the extreme rear of an aircraft fuselage or jet engine.
• TCASalso Traffic Collision Avoidance System, ACAS
  The Traffic Collision Avoidance System is an onboard avionics system that prevents mid-air collisions.
• Trailing edge
  The rearmost margin of an airfoil where the upper and lower airflows rejoin.
• ULCV
  An Ultra-Lightweight Combat Vehicle is a tactical buggy designed to be airdropped or carried by helicopters.
• Umbilicalalso umbilical cord, umbilicus
  A physical line providing power, fluids, or data to a vehicle or astronaut before separation.
• Umbilical cordalso umbilical
  A flexible lifeline supplying oxygen, cooling, and communications to an astronaut during a spacewalk.
• Umbilicusalso umbilical
  A rigid or flexible transfer tube connecting a spacecraft to a mothership or station.
• Uplock
  A mechanical latch that secures landing gear in its fully retracted position inside the wheel well.
• VIRTIS
  The Visible and Infrared Thermal Imaging Spectrometer is a scientific instrument used on space probes.
• Winglet
  A vertical or angled extension at the tip of an aircraft wing.

The procedures, flight paths, and tactical movements executed by pilots and automated systems.

• Aerobatics
  Intentional flight maneuvers involving extreme attitudes, spins, or loops.
• Aerobraking
  The use of atmospheric drag to slow a spacecraft and alter its orbit.
• Aerocapture
  A single-pass orbital insertion maneuver relying entirely on atmospheric drag.
• Air corridoralso flight corridor, airway
  A designated block of airspace through which aircraft are required to fly.
• Air-to-air
  Occurring between two or more aircraft while in flight.
• Aircraft station
  A mobile radio transceiver installation located on board an aircraft.
• Airspeed
  The velocity of an aircraft relative to the air mass it is flying through.
• Angle of attackalso AoA, alpha
  The acute angle between the chord line of an airfoil and the oncoming relative wind.
• Anteorbital
  Occurring during the flight phase just before a spacecraft achieves a stable orbit.
• Approach
  The final phase of a flight where an aircraft aligns with the runway for landing.
• ATOalso JATO, RATO
  Assisted take-off is a method of launching an aircraft using auxiliary thrust.
• Back to back ticketalso nested ticket
  A ticketing strategy using overlapping round-trip itineraries to bypass airline pricing rules.
• Backout
  A backout is the process of reversing a launch countdown to undo preparations after a hold.
• Backtrackalso back-taxi
  To backtrack is to taxi an aircraft on an active runway in the opposite direction of takeoff.
• Balloon
  To balloon is to unintentionally gain altitude during the landing flare due to excess airspeed. Shop talk
• Bandit
  A bandit is a military brevity term for an aircraft positively identified as an enemy. Shop talk
• Bingo
  A pre-calculated fuel state requiring an immediate return to base or diversion. Shop talk
• Black holealso black hole illusion, featureless terrain illusion
  A dangerous visual illusion occurring during night approaches over featureless terrain.
• Bogeyalso bogie
  An unidentified aircraft detected on radar or visually that has not been confirmed as friendly or hostile. Shop talk
• Bouncealso ballooning, porpoising
  To strike the runway during landing and rebound back into the air. Shop talk
• Buffet
  A low-frequency vibration felt in an aircraft when airflow separates from the wings.
• Buzzalso flat-hatting
  To fly an aircraft extremely low and fast over a specific ground target. Shop talk
• Cabréalso nose-high
  Describes an aircraft flying with a high pitch attitude, nose up and tail down.
• CASMalso unit cost
  Cost per Available Seat-Mile is a standard metric used to measure an airline's unit cost.
• CATO
  Catapult Assisted Takeoff is a launch method using a mechanical system to accelerate an aircraft.
• CAVU
  Ceiling and Visibility Unrestricted indicates perfect flying weather with no significant clouds or haze. Shop talk
• Cherubs
  A tactical brevity code used to state the altitude of friendly aircraft in hundreds of feet. Shop talk
• CLalso lift coefficient, coefficient of lift
  The lift coefficient is a dimensionless number that relates the lift generated by a lifting body to its dynamic pressure and area.
• Codeshare
  A commercial flight operated by one airline but marketed and sold by others.
• COLalso centre of lift
  The centre of lift is the focal point where all aerodynamic lifting forces act on an aircraft.
• Crabalso crabbing
  To point an aircraft slightly into the wind to maintain a straight track over the ground.
• CRMalso crew resource management, cockpit resource management
  Crew resource management is a training system focused on communication and teamwork to prevent aviation accidents.
• Cyclealso flight cycle
  One complete flight from takeoff to landing, used to track the lifespan of an airframe or engine.
• Dakota
  A brevity code indicating that an aircraft has expended all of its air-to-ground ordnance. Shop talk
• Deadstick landingalso deadstick
  A forced touchdown performed without engine power.
• Decayalso orbital decay, speed decay
  The gradual loss of airspeed or orbital altitude due to drag forces.
• Demate
  To physically separate two connected spacecraft or a spacecraft from its carrier aircraft.
• Deorbit burn
  A retrograde engine firing that slows a spacecraft enough to re-enter the atmosphere.
• Departalso depart controlled flight
  To unintentionally lose aerodynamic control of an aircraft. Shop talk
• Dipalso sinker
  A sudden, brief loss of altitude during flight, often caused by a downdraft. Shop talk
• Direct
  A routing that proceeds straight to a navigational waypoint without intermediate turns.
• Direct flight
  A commercial flight that retains the same flight number through an intermediate stop.
• Dirty
  Configured for landing with the landing gear and flaps extended. Shop talk
• Ditch
  To execute a forced landing of an aircraft on a body of water.
• Dive
  A steep, nose-down descent maneuver that rapidly trades altitude for airspeed.
• Endorsement
  An official logbook signature from an instructor certifying a pilot's proficiency in a specific skill.
• EOD
  The exact time when natural sunlight is no longer sufficient for visual flight operations.
• Excursionalso runway excursion
  A runway excursion is an incident where an aircraft veers off or overruns the runway surface.
• FD
  An avionics system that computes and displays the optimal pitch and bank angles for a pilot to fly.
• Fixalso waypoint
  A fix is a specific geographical position determined by visual reference or navigational instruments.
• FL
  A standardized altitude measurement expressed in hundreds of feet based on standard atmospheric pressure.
• FOP
  Form of payment, used in airline ticketing and reservation systems.
• Formate
  To join up and fly in close formation with another aircraft. Shop talk
• GAalso general aviation
  General aviation covers all civil flying except scheduled passenger airlines and military flights.
• Gammaalso flight path angle
  The flight path angle represents the angle between an aircraft's velocity vector and the horizontal plane.
• Ground effect
  The increased lift and decreased drag an aircraft experiences when flying very close to the surface.
• GTO
  Geostationary transfer orbit is an elliptical Earth orbit used to transfer a spacecraft to a geostationary orbit.
• HALO
  High altitude, low opening is a military parachuting technique used to evade detection.
• Hand-offalso handoff
  The transfer of radar identification and radio communication for an aircraft from one air traffic controller to another.
• Hassle
  To engage in mock air-to-air combat or dogfighting. Shop talk
• HBO
  Hand baggage only, a restricted airline fare class.
• HEO
  Highly elliptical orbit, an orbit with a high eccentricity.
• Hibernation
  A state of minimal power consumption for a spacecraft during long transit phases.
• Holding patternalso hold
  A holding pattern is a standardized racetrack-shaped flight path used to delay an aircraft in flight.
• Hypersonic
  Relating to speeds equal to or greater than five times the speed of sound.
• Icing
  The accumulation of ice on the external surfaces of an aircraft in flight.
• Innage
  The volume or weight of fuel remaining in an aircraft tank after a flight.
• JOI
  An abbreviation for Jupiter orbital insertion, the critical engine burn required to enter orbit around Jupiter.
• Kármán line
  The boundary generally recognized as the edge of space, located at an altitude of 100 kilometers above sea level.
• Kangaroo route
  The commercial air route connecting Australia and the United Kingdom via stopovers in the Eastern Hemisphere. Shop talk
• Kiss
  A gentle mid-air collision between the fabric envelopes of two hot air balloons. Shop talk
• Laser
  To illuminate an aircraft with a high-powered handheld laser pointer from the ground.
• Lead-lagalso hunting
  The horizontal back-and-forth movement of a helicopter rotor blade as it spins.
• Liftoffalso lift-off
  The exact moment a rocket or aircraft breaks physical contact with the ground.
• Lithobraking
  The humorous term for stopping a spacecraft by letting it crash into the ground. Shop talk
• LLOalso low lunar orbit
  Low Lunar Orbit is a close trajectory around the Moon used for observation and staging landings.
• LOCalso LOC-I, loss of control
  Loss of Control occurs when a pilot or autopilot can no longer maintain the aircraft's intended flight path.
• LOIalso lunar orbit insertion
  Lunar Orbit Insertion is the critical engine burn that places a spacecraft into orbit around the Moon.
• Loiter
  To remain airborne over a specific area or target for an extended period.
• Longline
  A heavy-duty cable suspended from a helicopter to carry external loads.
• LTE
  Loss of tail rotor effectiveness is an uncommanded yaw condition in helicopters.
• LTO
  A lunar transfer orbit is the trajectory a spacecraft takes to travel from Earth to the Moon.
• max Qalso maximum dynamic pressure
  The point during a rocket launch when aerodynamic stress on the vehicle is at its absolute highest.
• Midairalso midair collision, MAC
  A collision or near-collision between two aircraft while in flight. Shop talk
• Milealso nautical mile, NM
  The standard unit of distance in aviation operations, universally referring to the nautical mile. Shop talk
• Milk run
  A routine, uneventful flight or a scheduled route with multiple stops. Shop talk
• Missed approachalso go-around
  A published procedure a pilot follows when an instrument approach cannot be completed to a landing.
• MSAalso minimum safe altitude
  Minimum sector altitude, the lowest cleared altitude that provides safe clearance above obstacles.
• NATalso North Atlantic Tracks, NAT OTS
  The North Atlantic Tracks are daily optimized flight routes across the Atlantic Ocean.
• Nonstop
  A flight that travels from the origin to the destination without landing.
• Paint
  To successfully detect and track an aircraft or object using a radar system. Shop talk
• Power dive
  A power dive is a steep, rapid descent accelerated by the aircraft's engines running at high thrust.
• PPL
  The Private Pilot Licence is a certification that permits an individual to fly an aircraft for non-commercial purposes.
• Probe-and-drogue
  An aerial refueling method where a receiver aircraft flies a rigid probe into a trailing hose basket.
• Protect
  To secure a backup reservation for a passenger whose original flight is likely to be delayed or canceled. Shop talk
• Pull-outalso recovery
  A flight maneuver to arrest a descent and return an aircraft to level flight.
• Punch outalso bail out, eject
  An emergency command or action to eject from a failing military aircraft using an ejection seat. Shop talk
• Re-entry
  The phase of a space mission where a vehicle plunges back into a planetary atmosphere.
• Rendezvous
  A series of orbital maneuvers that bring two spacecraft into close proximity.
• Rhubarb
  A low-level fighter sweep conducted to find and attack ground targets of opportunity. Shop talk
• Roll rate
  The speed at which an aircraft can rotate around its longitudinal axis.
• RTOalso aborted takeoff
  A rejected takeoff occurs when a pilot aborts the departure roll before the aircraft leaves the ground.
• Run-upalso engine run-up
  A pre-flight testing sequence performed to verify engine and system health before takeoff.
• Scissorsalso rolling scissors, flat scissors
  A defensive dogfighting maneuver where two aircraft repeatedly turn toward each other.
• SECO
  The exact moment a launch vehicle shuts down its sustainer engine.
• Sectoralso leg
  A single flight leg from takeoff to landing, including the associated ground preparation.
• SES
  The moment a launch vehicle ignites its sustainer engine.
• Skid
  An uncoordinated flight maneuver where the aircraft's tail swings outward from the direction of a turn.
• Slingloadalso external load
  Cargo suspended below a helicopter by cables or nets during flight.
• Slingshot effectalso gravity assist, swing-by
  A maneuver that uses a planet's gravity and orbital momentum to accelerate or decelerate a spacecraft.
• Snatchalso aileron snatch, control snatch
  A sudden, uncommanded jerking of an aircraft's control surfaces caused by shock waves at transonic speeds.
• Soft landing
  A controlled touchdown that preserves the structural integrity of a spacecraft or its payload.
• Sonic boom
  The loud noise caused by the shock wave of an aircraft traveling faster than the speed of sound.
• Sortie
  A single operational flight mission conducted by an individual military aircraft.
• Speedball
  An improvised aerial resupply package dropped to ground forces. Shop talk
• Spoil
  To intentionally disrupt the smooth flow of air over a wing to reduce lift.
• Squawk
  To transmit a specific four-digit transponder code for air traffic control radar. Shop talk
• Standby
  A travel status where a passenger waits at the gate for an unassigned seat to open up.
• T-minus
  A countdown protocol indicating the time remaining before a scheduled launch or major sequence.
• TAalso Traffic Advisory
  A Traffic Advisory alerts pilots to another aircraft flying nearby.
• Tailspinalso spin
  A rapid and uncontrolled spiral descent in a stalled condition.
• Taxi
  The movement of an aircraft on the ground under its own engine power.
• TCAalso Terminal Control Area
  A Terminal Control Area is a designated block of airspace around a busy airport.
• TDalso Ticket Designator
  A Ticket Designator is an alphanumeric code added to a passenger fare to indicate a special discount or condition.
• Terrain
  The physical surface of the earth beneath an aircraft in flight.
• Theta
  The pitch angle of an aircraft relative to the horizontal plane.
• Thin
  Describing an airline route with low passenger demand or infrequent service. Shop talk
• Ticket designator
  An alphanumeric code on an airline ticket indicating a specific fare type or discount.
• TLIalso trans-lunar injection
  Trans-lunar injection is a propulsion maneuver that sets a spacecraft on a trajectory to the Moon.
• Toboggan
  To enter a shallow dive to build airspeed for an aerial refueling maneuver. Shop talk
• Touchdown
  The exact moment an aircraft or spacecraft makes contact with the landing surface.
• TPM
  Ticket point mileage is the actual geographic distance between two cities on an airline itinerary.
• Trajectory
  The three-dimensional flight path of an aircraft, rocket, or spacecraft.
• Transfer window
  A specific timeframe when a spacecraft can depart one body to intercept another using minimal fuel.
• Transition
  A published flight path connecting the en-route structure to an approach or departure procedure.
• Turbulencealso chop, rough air
  Irregular atmospheric motion that causes an aircraft to bounce or jolt in flight.
• Unable
  A standard radio call indicating that a pilot or controller cannot comply with a specific instruction.
• Unberth
  To detach a spacecraft from a station using a robotic arm rather than the craft's own thrusters.
• Undock
  To detach a spacecraft from another vessel and fly away using onboard propulsion.
• Uplift
  The act of loading fuel, cargo, or passengers onto an aircraft prior to departure.
• VD
  The absolute maximum design diving speed an airframe is engineered to survive during flight testing.
• Vectoralso radar vector
  A specific magnetic heading assigned by air traffic control to guide an aircraft.
• VUSA
  A Visit USA fare is a discounted domestic airline ticket sold to international travelers. Shop talk
• Wet
  A wet thrust setting means the engine is using afterburners or fluid injection for extra power. Shop talk
• Wet leasealso ACMI lease
  An arrangement where one airline provides an aircraft, complete crew, maintenance, and insurance to another airline.
• Wheelbarrow
  A landing error where the aircraft's weight is forced onto the nose gear. Shop talk
• Wing in ground effectalso ground effect
  The aerodynamic phenomenon where a wing generates extra lift and less drag near the surface.
• XC
  The abbreviation for a cross-country flight, which involves navigating between different airports.

The technologies and physical processes used to generate thrust for jets, helicopters, and rockets.

• Airbreathing
  An engine design that relies on atmospheric oxygen to burn its fuel.
• Bliskalso integrally bladed rotor, IBR
  A single engine component consisting of a rotor disk and blades machined from one solid piece of metal.
• Burnalso engine burn, firing
  A scheduled firing of a spacecraft propulsion system to alter its trajectory.
• Chemical rocket
  A propulsion system that generates thrust through the exothermic reaction of chemical propellants.
• Combined cycle
  An engine system that integrates multiple propulsion methods to operate efficiently.
• Core lock
  The mechanical seizure of a jet engine caused by unequal cooling of its internal components.
• Delta-v
  The total change in velocity a spacecraft can achieve using its available propellant.
• Diskalso disking
  To flatten the pitch of propeller blades to maximize aerodynamic drag.
• ECO
  Engine cutoff is the exact moment a rocket engine stops producing thrust.
• Exhaust velocity
  The speed at which propellant gases exit a rocket nozzle or jet engine.
• FCU
  The fuel control unit is a hydro-mechanical or electronic device that meters the exact amount of fuel entering a gas turbine engine.
• Flox
  A highly reactive rocket propellant mixture of liquid fluorine and liquid oxygen.
• Fusion rocket
  A fusion rocket is a theoretical spacecraft engine powered by nuclear fusion.
• Gas generator
  A gas generator burns propellant to create high-pressure gas that drives turbines or pumps.
• Gimbal
  To gimbal is to swivel a rocket engine or thruster to steer the vehicle.
• Grainalso propellant grain
  The solid mass of propellant cast inside a solid rocket motor.
• Hard start
  A damaging overpressure event or explosion that occurs when a rocket engine ignites with excess propellant in the combustion chamber.
• Hydroloxalso LH2/LOX
  A high-performance rocket propellant mixture of liquid hydrogen and liquid oxygen.
• Hypergolicalso hypergols
  Describing a rocket propellant combination that ignites spontaneously upon contact.
• Ingest
  To suck foreign objects, debris, or wildlife into a jet engine intake.
• Ion engine
  A spacecraft thruster that accelerates charged particles using an electric field to generate thrust.
• Magnetoplasmadynamicsalso MPD
  The study of how magnetic fields interact with electrically conducting fluids like plasma.
• MECO
  Main Engine Cut-Off is the moment during a rocket launch when the primary engines are commanded to shut down.
• MPS
  Main propulsion system, the primary cluster of engines and plumbing that drives a launch vehicle.
• NTRalso Fission rocket
  A nuclear thermal rocket, an engine that uses a reactor to heat propellant.
• Nuclear-electric rocketalso NEP
  A spacecraft propulsion system pairing a nuclear reactor with an electric thruster.
• Nuclear rocket
  A rocket engine that derives its thrust or power from a nuclear reactor.
• Nuclear-thermal rocketalso NTR
  A propulsion system that uses a fission reactor to heat and expand a propellant.
• Nuclear-thermoelectric rocket
  A hybrid propulsion system combining nuclear heating and electrical ionization.
• OMS
  The Orbital Maneuvering System provides thrust for spacecraft orbital changes.
• Pogoalso pogo oscillation, pogo effect
  A dangerous longitudinal vibration in a liquid-fueled rocket caused by combustion instability. Shop talk
• Power-eggalso engine module, quick engine change unit
  A self-contained, modular engine package designed to be quickly swapped out of an aircraft as a single unit.
• Preburner
  A small combustion chamber in a staged-combustion rocket engine used to drive the turbopumps.
• Propulsoralso ducted fan
  A shrouded or ducted propeller system used to generate thrust.
• Pyrogen
  A highly flammable chemical mixture used to initiate the ignition sequence in solid rocket motors.
• Ramjet
  An airbreathing jet engine that uses the vehicle's forward motion to compress incoming air.
• RP-1
  Rocket Propellant-1, a highly refined form of kerosene used as rocket fuel.
• Scramjet
  An airbreathing jet engine that operates with supersonic airflow through its combustion chamber.
• SE
  The sustainer engine that provides long-duration thrust after a launch vehicle drops its boosters.
• Solar sailalso light sail, photon sail
  A propulsion system that uses large, highly reflective membranes to generate thrust from the radiation pressure of sunlight.
• Solid rocketalso solid rocket motor, SRM
  A rocket motor that uses a pre-mixed, solid state propellant.
• Spool
  A rotating assembly inside a gas turbine engine consisting of a compressor, a shaft, and a turbine.
• SRB
  A solid rocket booster used to provide heavy initial thrust during a launch.
• Strap-onalso strap-on booster, SRB
  An auxiliary rocket booster attached to the side of a core launch vehicle to provide extra thrust at liftoff.
• Sustaineralso sustainer engine
  A rocket engine designed to burn continuously from liftoff through the later stages of ascent.
• Turbojet
  An airbreathing jet engine that generates all its forward thrust directly from high-velocity exhaust gas.
• VSV
  Variable stator vanes are adjustable blades inside a jet engine compressor.
• Working massalso reaction mass, propellant mass
  The physical matter ejected by a rocket or thruster to generate propulsion.

The physical facilities, ground equipment, and designated zones required to support flight operations.

• Airfield
  A designated area of land or water used for the takeoff, landing, and movement of aircraft.
• Apronalso ramp, tarmac
  The paved area at an airport where aircraft are parked, loaded, refueled, or boarded.
• Commercial
  Relating to airports or flight operations that handle paying passengers and cargo.
• Cross-border ticket
  An airline itinerary booked from a different country to exploit regional pricing differences.
• DIAalso DEN, KDEN
  Denver International Airport is a massive, high-altitude commercial aviation hub located in Colorado.
• DME
  Distance measuring equipment is a radio navigation technology that calculates the slant range between an aircraft and a ground station.
• Erectoralso transporter erector
  A heavy vehicle or structure that transports a rocket and raises it vertically onto the launch pad.
• ETalso e-ticket
  A digital record of a passenger's booking that replaces a traditional paper document.
• Go-show
  A passenger who arrives at the airport hoping to fly on an earlier flight than the one they booked. Shop talk
• HIF
  A ticketing rule that checks for a higher intermediate fare along a routed journey.
• HIP
  A specific stopover location that triggers a higher intermediate fare calculation.
• Kk
  A status code used in airline reservation systems to confirm a passenger's seat request. Shop talk
• Landing stripalso airstrip
  A basic, unpaved or temporary runway used for aircraft operations.
• LCalso Launch Complex
  The designated area and infrastructure used to prepare and launch rockets.
• MCO
  An older accounting document used by airlines to process payments for non-ticket services.
• Minimum connecting timealso MCT
  The standard baseline time required to transfer a passenger and their baggage between two flights.
• Movement
  A single takeoff or landing operation by an aircraft at an airport.
• Ouija board
  A tabletop scale model used in aircraft carrier flight control to track deck operations. Shop talk
• Pieralso concourse
  A pier is a long, narrow concourse extending from a main airport terminal that houses multiple boarding gates.
• PNRalso passenger name record, record locator
  The alphanumeric reservation code that connects a passenger to their complete flight itinerary and booking details.
• PSRalso primary surveillance radar, primary radar
  The traditional radar system that bounces radio waves off objects to detect their position.
• RR
  A legacy reservation status code indicating a passenger's flight segment is reconfirmed. Shop talk
• RSA
  The Runway Safety Area, a cleared zone surrounding a runway designed to reduce the risk of damage during an excursion.
• Runwayalso landing strip, airstrip
  A defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft.
• Suspend
  To temporarily invalidate a specific flight coupon in a passenger's itinerary without canceling the entire ticket.
• Tarmac
  The paved surface at an airport where aircraft park, load, and maneuver. Shop talk
• TEalso Transporter-Erector, strongback
  A Transporter-Erector is a heavy vehicle used to move a rocket to the launch pad and raise it vertically.
• TGSalso taxiing guidance system
  A Taxiing Guidance System helps direct aircraft safely on the ground.
• Threshold
  The designated beginning of the usable landing area on a runway.
• Turnaroundalso turn
  The process of servicing and preparing an aircraft between its arrival and its next departure.
• Vertiport
  A dedicated facility designed for the takeoff, landing, and servicing of vertical takeoff and landing aircraft.

The informal nicknames, job titles, and cultural shorthand shared among aviation professionals.

• Air hostessalso stewardess
  A historic title for a female crew member responsible for passenger safety and comfort aboard a commercial aircraft.
• Batsmanalso LSO, paddles
  A batsman is the historic term for a landing signal officer who guided aircraft using hand-held paddles. Shop talk
• Boffinalso egghead, propellerhead
  A technical expert, research scientist or aerospace engineer who works on complex design problems. Shop talk
• Captainalso pilot in command, PIC
  The pilot in command who holds ultimate legal authority and responsibility for an aircraft.
• CCMalso flight attendant
  A Cabin Crew Member is a trained professional responsible for passenger safety and service on a commercial flight.
• Companyalso company traffic
  A radio shorthand used by pilots and controllers to refer to another aircraft from the same airline. Shop talk
• DOJ
  A double open jaw is an airline itinerary where both the origin and destination cities change on the return trip.
• Flyboyalso jet jockey, throttle jockey
  A slang nickname for a male pilot that often implies a brash or overconfident attitude. Shop talk
• George
  A traditional nickname used by flight crews for an aircraft autopilot system. Shop talk
• Jet lag
  A temporary sleep disorder caused by traveling quickly across multiple time zones.
• QAIalso QA
  Quality Assurance Inspector, a maintenance professional who verifies that aircraft repairs meet safety standards.
• Shirtalso First Shirt
  The informal nickname for a First Sergeant in the United States Air Force. Shop talk
• SOBalso souls on board, POB
  The abbreviation for souls on board, representing the total number of living people on an aircraft. Shop talk
• Steely-eyed missile man
  A highly competent aerospace professional who solves critical problems under extreme pressure. Shop talk
• TCPalso To Complete Party
  A ticketing code indicating that a passenger is traveling with others booked on a separate record.

The organizations, regulatory bodies, and specific exploratory programs that define the aerospace industry.

• ALMA
  The Atacama Large Millimeter/submillimeter Array, a massive radio telescope in Chile.
• Apollo
  The historic United States space program that successfully landed humans on the Moon.
• Artemis
  The crewed spaceflight program led by the United States to return astronauts to the Moon and establish a sustainable lunar presence.
• C3PO
  The Commercial Crew and Cargo Program Office that manages private spaceflight contracts.
• CAPCOMalso Capsule Communicator
  Short for Capsule Communicator, this is the designated flight controller who speaks directly with the astronaut crew during a space mission.
• CCDev
  Commercial Crew Development is a NASA program funding private companies to build crewed spacecraft.
• ChemCamalso Chemistry and Camera
  Chemistry and Camera is an instrument suite on the Mars Curiosity rover that analyzes rock composition.
• CheMinalso Chemistry and Mineralogy
  Chemistry and Mineralogy is an analytical instrument on the Mars Curiosity rover.
• CIBERalso Cosmic Infrared Background Experiment
  The Cosmic Infrared Background Experiment is a sounding rocket payload designed to measure extragalactic background light.
• COTS
  Commercial Orbital Transportation Services was a program to fund private cargo flights to space.
• Countdown
  A strict backward schedule of tasks leading up to the launch of a rocket or spacecraft.
• DRO
  A distant retrograde orbit is a highly stable lunar orbit that moves in the opposite direction of the Moon's rotation.
• DSN
  The Deep Space Network is an international array of giant radio antennas that supports interplanetary spacecraft missions.
• EAC
  The European Astronaut Centre is the facility responsible for training and supporting European astronauts.
• ECSS
  The European Cooperation for Space Standardization is an initiative that produces a single set of standards for European space projects.
• eLISAalso LISA
  The evolved Laser Interferometer Space Antenna is a planned space mission to detect and measure gravitational waves.
• Emirates
  The largest airline and flag carrier of the United Arab Emirates, based in Dubai.
• ESA
  European Space Agency, an intergovernmental organization coordinating Europe's space exploration.
• ESOC
  European Space Operations Centre, the main mission control facility for the European Space Agency.
• ESRIN
  European Space Research Institute, the ESA facility managing Earth observation data.
• ESTEC
  European Space Research and Technology Centre, ESA's primary spacecraft design and testing facility.
• FLPP
  The Future Launchers Preparatory Programme, a European Space Agency initiative.
• GALEXalso Galaxy Evolution Explorer
  The Galaxy Evolution Explorer is a space-based observatory built to map the universe in ultraviolet light.
• GRAIL
  The Gravity Recovery and Interior Laboratory was a lunar science mission that mapped the Moon's gravity field.
• HiRISE
  A powerful telescopic camera system mounted on the Mars Reconnaissance Orbiter.
• HS3
  An airborne science mission designed to investigate the formation of severe storms.
• IIST
  The Indian Institute of Space Science and Technology is a government-backed aerospace university.
• INTEGRAL
  The International Gamma-Ray Astrophysics Laboratory is an ESA space observatory.
• ISEE
  An abbreviation for International Sun-Earth Explorer, a historic series of spacecraft built to study space weather.
• JCSS
  An abbreviation for Joint Functional Component Command for Space, a military organization managing orbital assets.
• JPL
  The Jet Propulsion Laboratory is a federally funded research center managed by Caltech for NASA.
• JUICE
  The Jupiter Icy Moons Explorer is an interplanetary spacecraft operated by the European Space Agency.
• JWSTalso Webb
  The James Webb Space Telescope is a large infrared observatory positioned at the Sun-Earth L2 Lagrange point.
• Launch window
  The specific timeframe during which a spacecraft must lift off to reach its intended orbit or target.
• LCROSS
  The Lunar Crater Observation and Sensing Satellite was a robotic spacecraft designed to detect water on the Moon.
• LDCMalso Landsat 8
  The Landsat Data Continuity Mission was the developmental name for the Earth observation satellite known as Landsat 8.
• LDSD
  The Low-Density Supersonic Decelerator is a project to develop atmospheric entry systems for heavy payloads landing on Mars.
• LISA
  The Laser Interferometer Space Antenna is a planned space-based gravitational wave observatory.
• LPRP
  The Lunar Precursor Robotic Program was a series of uncrewed missions to map the Moon.
• LPSC
  The Lunar and Planetary Science Conference is an annual gathering of planetary scientists.
• LRO
  The Lunar Reconnaissance Orbiter is a robotic spacecraft mapping the Moon's surface.
• LWS
  The NASA research program dedicated to studying the Sun-Earth system and space weather.
• MAVEN
  The Mars Atmosphere and Volatile Evolution Mission is a NASA orbiter studying the Martian upper atmosphere.
• MEDLI
  MSL Entry, Descent, and Landing Instrumentation is a sensor suite used on the Mars Science Laboratory heat shield.
• MEP
  The Mars Exploration Program is a sustained initiative by NASA to explore the planet Mars.
• MER
  The Mars Exploration Rover mission was a NASA project that sent robotic rovers to the Martian surface.
• MGS
  The Mars Global Surveyor was a NASA orbital mission that mapped the Martian surface and weather.
• Moonwalkalso lunar EVA
  An extravehicular activity conducted by an astronaut on the lunar surface.
• MPO
  Mercury Planetary Orbiter, a European Space Agency spacecraft designed to map Mercury.
• MSRalso Mars Sample Return
  The Mars Sample Return is a proposed multi-stage spaceflight campaign to bring Martian rock and soil back to Earth.
• MTFalso Mississippi Test Facility, Stennis Space Center
  The historic name for the major NASA rocket engine testing complex located in Hancock County.
• NextSTEPalso Next Space Technologies for Exploration Partnerships
  A public-private partnership program designed to fund commercial deep space exploration technologies.
• NLSalso National Launch System
  The National Launch System was a historic study for a modular family of heavy-lift rockets.
• NPOESS
  The National Polar-orbiting Operational Environmental Satellite System.
• NPPalso Suomi NPP
  The NPOESS Preparatory Project, a weather and climate monitoring satellite.
• OST
  The Outer Space Treaty forms the foundational legal framework for international space law.
• PAL
  Philippine Airlines is the national flag carrier airline of the Philippines.
• Qantas
  The flag carrier airline of Australia and one of the oldest operating airlines in the world.
• RAAF
  The Royal Australian Air Force serves as the principal aerial warfare branch of the Australian Defence Force.
• RAF
  The Royal Air Force, the United Kingdom's aerial warfare branch.
• RBSP
  The Radiation Belt Storm Probes, a pair of NASA satellites designed to study the Van Allen radiation belts.
• RFCalso Royal Flying Corps
  The Royal Flying Corps was the historic military aviation branch of the British armed forces.
• RVSP
  The Rover Sequencing and Visualization Program used to model terrain and plan drives for Martian rovers.
• SAM
  The Sample Analysis at Mars instrument suite aboard the Curiosity rover.
• SIRTF
  Space Infrared Telescope Facility, the original developmental name for the Spitzer Space Telescope.
• SMOS
  The Soil Moisture and Ocean Salinity satellite is an Earth observation mission designed to map global water cycles.
• SMPG
  The Small Mission Program Group oversees low-budget, highly focused exploratory space missions.
• SOFIA
  The Stratospheric Observatory for Infrared Astronomy was an airborne telescope mounted inside a modified Boeing 747SP.
• SOHO
  The Solar and Heliospheric Observatory is a spacecraft dedicated to studying the internal structure and outer atmosphere of the Sun.
• Space medicine
  The medical discipline focused on the physical and psychological effects of spaceflight on humans.
• SPEalso solar proton event
  A solar particle event, where the sun emits a massive burst of high-energy protons.
• SSA
  Space Situational Awareness, the tracking of orbital debris and space weather.
• SSED
  The Solar System Exploration Division is a NASA directorate responsible for investigating planets, moons, and small bodies.
• TGOalso Trace Gas Orbiter
  Trace Gas Orbiter is a spacecraft designed to analyze the Martian atmosphere.
• ULA
  United Launch Alliance is a major American aerospace joint venture that manufactures and operates rockets.
• USB
  Unified S-band is a historic tracking and communication system developed for the Apollo lunar missions.
• USOS
  The United States Orbital Segment is the portion of the International Space Station operated by NASA and its international partners.
• VAST
  The Volcanic Ash Strategic Initiative Team is a collaborative group managing aviation safety around volcanic eruptions.
• VEX
  Venus Express was a European Space Agency mission to study the atmosphere of Venus.