Definitions list
  • La Niña
    Climatic phenomenon observed in the Pacific Ocean that follows certain El Niño events. Its effects are opposite, causing surface waters to cool and sea level to fall.
  • lander
    Spacecraft designed to land on the surface of a planet or celestial object.
  • launch area
    Area where the facilities required for final preparation and launch of a spacecraft are located.
  • launch base
    Base where satellites are launched. A launch base provides facilities required for satellite preparation and final assembly, fuelling and launch, and for post-launch tracking. There are 15 launch bases operating in the world today.
    The Guiana Space Centre
  • launch campaign
    Period spanning preparation of the payload and its launch vehicle at the launch base, and launch vehicle operations. Also used for balloon launches.
    How launchers work
  • launch complex
    A launch complex houses the facilities required to prepare and launch a spacecraft. It may comprise a launch area, staging area, launch control centre and assembly buildings.
  • launch control centre
    Facility located near the launch area, usually protected against blasts or impacts, where launch vehicle operations up to lift-off are directed. It houses the equipment required to remotely control and command electrical and fluid circuits, and systems for monitoring the launch vehicle and its environment.
  • launch pad
    Area where the facilities required for final preparation and launch of a spacecraft are located. Synonym: launch area.
  • launch ramp
    Orientable structure used to support and guide a launch vehicle on the launch pad. It provides the electrical connections and fluid lines between the launch vehicle and ground support equipment.
  • launch system
    Term encompassing all the facilities, equipment and resources required to place a payload into its intended orbit. It comprises the launch vehicle, its production and test facilities, and all the ground support equipment needed for launch operations.
  • launch table
    Horizontal, fixed or mobile platform that supports and holds the lower part of a launch vehicle until lift-off.
  • launch window
    Interval during which a spacecraft may be launched at any moment. The launch window is usually determined by the nature of the mission.
  • launcher
    Vehicle designed to place a man-made satellite into orbit. Synonym: rocket
    How launchers work
  • lidar
    Uses the same principle as radar and transmits light out to a target. Acronym for "Light detection and ranging."
  • light-year
    Unit of distance used in astronomy. It is the distance travelled by light moving in a vacuum in the course of one year, at its accepted velocity of 300,000 kilometres per second. One light-year equals about 9,460 billion km. At this scale, the Sun is 8.3 light-minutes from Earth.
  • location
    Determination of the position of a point with respect to a reference system. In space terminology, it denotes the determination of a spacecraft’s position with respect to Earth, or the position of a mobile (a transmitter or beacon, for example) on the surface of the globe.
  • low Earth orbit
    Orbit of a man-made satellite whose altitude at apogee is low compared to a geostationary orbit. The exact altitude depends on the satellite’s mission. When referring to the capability of a launch vehicle, low-Earth orbit is at around 200 km. For satellites, it may be several thousand kilometres. Telecommunications satellites orbit at about 1,000 km.
    What is an orbit?