Glossary - L

L band
frequency range from 0.5 to 1.5 GHz
(communications)

Launcher
rocket designed to lift one or more spacecraft from the surface of the Earth into space (usually into orbit)
(launcher technology)

Launcher adapter
the structure which is used to attach one or more spacecraft to the top of the launcher
(launcher technology)

Life support system
a system designed to maintain the environment in a spacecraft or spacesuit so that it is comfortable for human crew members by controlling atmospheric composition and pressure, temperature and humidity, managing waste and the supply of drinkable water, as well as fire detection and suppression
(human spaceflight)

Link budget
standard way of calculating the performance that can be achieved by a particular link, for example from an earth station, through a satellite to a second earth station
(communications)

Liquid propellant
the liquid fuel and oxidiser used in most rockets; liquid propellants are generally classified as being "storable" which can be stored at room temperature or "cryogenic" which are liquefied gases; examples are: storable fuels - UDMH and hydrazine, cryogenic fuels - liquid hydrogen (LH2), storable oxidiser - nitrogen tetroxide, cryogenic oxidiser - liquid oxygen (LOX)
(launcher technology)

Little LEO
low earth orbit satellite for only data communications
(orbits)

Low Earth Orbit (LEO)
an orbit of altitude between 200 and 1000 km above the Earth
(orbits)

Low Noise Amplifier (LNA)
a preamplifier, generally located as near to the antenna feed as possible, which has a very low noise figure and which is used to boost the receive signal level for transmission across the site to the receiver(s); ensures that signals are received with the minimum of additional noise
(communications, spacecraft technology, earth station technology)

Low noise block downconverter
a combined low noise amplifier and downconverter in a single device which is mounted on an antenna feed
(earth station technology)

Lunar Gateway
a space station planned as part of the Artemis program which will be placed in lunar orbit which is intended to be used as a staging post for astronauts travelling to and from the lunar surface, a communications hub, an orbiting science laboratory and as a holding area for lunar rovers and robots
(human spaceflight, space exploration)