| LCC | Launch Control Complex | In English | |
| LCC | Launch Commit Criteria | In English | |
| LCC | Launch Control Center | In English | |
| LCCD | Launch Commit Criteria Document | In English | |
| LCE | Launch Complex Engineer | In English | |
| LCE | Launch Complex Equipment | In English | |
| LCMS | Low-Cost Modular Spacecraft | In English | |
| LCROSS | Lunar Crater Observation and Sensing Satellite | In English | → Astronomy |
| LCS | Launch Control System | In English | |
| LDEC | Lunar Docking Events Controller | In English | |
| LDIU | Launch Data Interface Unit | In English | → Human-computer interaction |
| LDS | Landing, Deservicing, and Safing | In English | → Aeronautics, aircraft |
| LDS | Launch Detection Satellite | In English | |
| LEH | Launch and Entry Helmet | In English | |
| LEM | Launch Escape Monitor | In English | |
| LEM | Lunar Excursion Module | In English | → Planets and satellites |
| LEO | Low Earth Orbit | In English | → Astronomy |
| LES | Launch-Entry Suit | In English | |
| LES | Lincoln Experimental Satellite | In English | |
| LES | Launch Escape Subsystem | In English | |
| LES | Launch Equipment Shop | In English | |
| LETF | Launch Equipment Test Facility | In English | |
| LEV | Lunar Excursion Vehicle | In English | |
| LF | Launch Facility | In English | |
| LFV | Lunar Flying Vehicle | In English | |
| LGS | Landing Gear Subsystem | In English | |
| LGTA | Landing Gear Test Article | In English | |
| LLCF | Launch and Landing Computational Facility | In English | → Computer science |
| LLO | Low Lunar Orbit | In English | → Astronomy |
| LLP | Launch and Landing Project | In English | |
| LLPO | Launch and LAnding Project Office | In English | |
| LM | Lunar Module | In English | |
| LM&SS | Lunar Mapping and Scientific Survey | In English | → Astronomy |
| LMDE | Lunar Module Descent Engine | In English | |
| LME | Launch Monitor Equipment | In English | → Aeronautics, aircraft |
| LMF | Lower Mid Fuselage | In English | → Aeronautics, aircraft |
| LMSC | Lockheed Missiles And Space Corporation | In English | → Military engineering |
| LMSS | Lunar Mapping and Survey System | In English | → Astronomy |
| LMSS | Land Mobile Satellite System | In English | |
| LOA | Landing Operations Area | In English | → Aeronautics, aircraft |
| LOA | Launch Operations Area | In English | |
| LOB | Launch Operations Building | In English | |
| LOC | Launch Operations Center | In English | |
| LOC | Launch Operations Complex | In English | |
| LOC | Launch Operations Contractor | In English | |
| LOCB | Launch Operations Control BUilding | In English | |
| LOD | Launch Operations Directorate | In English | |
| LOD | Launch Operations Division | In English | |
| LOD | Launch Order Document | In English | |
| LOI | Lunar Orbit Insertion | In English | → Astronomy |
| LON | Launch On Need | In English | |
| LOO | Launch Operations Orders | In English | |
| LOP | Launch Operations Panel | In English | |
| LOR | Lunar Orbit Rendezvous | In English | → Astronomy |
| LOSP | Landing Operations Support Panel | In English | → Aeronautics, aircraft |
| LOSS | Lunar Orbital Space Station | In English | |
| LOWG | Landing Operations Working Group | In English | → Aeronautics, aircraft |
| LPD | Landing Point Designator | In English | → Aeronautics, aircraft |
| LPD | Launch Procedure Document | In English | |
| LPD | Launch Preparation Document | In English | |
| LPG | Liquid-Propellant Gun | In English | |
| LPIF | Launch Package Integration Facility | In English | |
| LPLWS | Launch Pad Lightning Warning System | In English | → Meteorology, climatology |
| LPS | Launch Processing System | In English | |
| LR | Luft und Raumfahrt | In German | → Serial publications, periodicals → Aeronautics, aircraft |
| LRB | Liquid Rocket Booster | In English | |
| LRD | Launch Recovery Division | In English | |
| LRD | Launch Requirements Document | In English | |
| LRE | Liquid Rocket Engine | In English | |
| LRES | Liquid Rocket Engine Stability Program | In English | |
| LRF | Liquid Rocket Fuel | In English | |
| LRO | Lunar Reconnaissance Orbiter | In English | → Astronomy |
| LRR | Launch Readiness Review | In English | |
| LRV | Lunar Roving Vehicle | In English | → Vehicle engineering |
| LRV | Launch Readiness Verification | In English | |
| LRW | Left Rendezvous Window | In English | |
| LS | Launch Site | In English | |
| LS | Launch Sequence | In English | |
| LS | Landing Site | In English | |
| LS/PPF | Launch Site PAyload Processing Facility | In English | |
| LSA | Launch Services Agreement | In English | |
| LSAH | Launch Site Accommodations Handbook | In English | |
| LSAP | Launch Sequence Applications Program | In English | |
| LSB | Launch Support Building | In English | |
| LSIC | Launch Support Integration Contractor | In English | |
| LSIC | Launch System Integration Contractor | In English | |
| LSID | Launch Sequence and Interlock Document | In English | |
| LSOC | Launch Support Operations Contractor | In English | |
| LSOC | Lockheed Space Operations Company | In English | |
| LSPDF | Life Science Payload Development Facility | In English | → Biological sciences |
| LSR | Launch Support Request | In English | |
| LSR | Launch Site Recovery | In English | |
| LSS | Landing and Separation Simulator | In English | |
| LSS | Large Space Structure | In English | |
| LSSL | Life Sciences Space Laboratory | In English | → Research institutes → Biological sciences |
| LSSRC | Life Sciences Shuttle Research Centrifuge | In English | → Biological sciences |
| LSTE | Launch Site Transportation Equipment | In English | → Transport and postal services |
| LSTS | Launch Site Test Set | In English | |
| LTV | Lunar Transfer Vehicle | In English | → Vehicle engineering |
| LuRaQ | Luft und Raumfahrt Quarter | In German | → Serial publications, periodicals → Aeronautics, aircraft |
| LUT | Launch Umbilical Tower | In English | |
| LVFRR | Launch Vehicle Flight Readiness Review | In English | → Aeronautics, aircraft |
| LVIP | Launch Vehicle Integration Plan | In English | → Aeronautics, aircraft |
| LVO | Launch Vehicle Operations | In English | → Aeronautics, aircraft |
| LVS | Launch Vehicle Simulator | In English | → Aeronautics, aircraft |
| LWD | Launch Window Display | In English | |
| MADCS | Modular Attitude Determination and Control System | In English | |
| MAEP | Minimum Autoland Entry Point | In English | → Aeronautics, aircraft |
| MAGSAT | Magnetometer Satellite | In English | → Physics → Earth sciences |
| MAL | Mobile Airlock | In English | → Aeronautics, aircraft |
| MAN | Microwave Aerospace Navigation | In English | → Aeronautics, aircraft |
| MAPS | Measurement of Air Pollution from Satellites | In English | → Nature → Meteorology, climatology |
| MARS | Manned Astronautical Research Station | In English | |
| MAS | Medium-Altitude Sensor | In English | → Aeronautics, aircraft |
| MASDC | Military Aircraft Storage and Disposition Center | In English | → Military engineering |
| MASSPO | Manned Spaceflight Support Project Office | In English | |
| MBAC | Marshall Booster Assembly Contractor | In English | |
| MCA | Maximum Crossing Altitude | In English | → Aeronautics, aircraft |
| MCT | Maximum Climb Thrust | In English | → Aeronautics, aircraft |
| MDRS | Mars Desert Research Station | In English | → Astronomy |
| MECSLSI | Mission Equipment Cargo Shuttle Launch Site | In English | |
| MEM | Meteoroid Exposure Module | In English | → Astronomy |
| MEM | Mars Excursion Module | In English | |
| MEMMS | Modélisation des Écosystemes Marins et Monitoring par Satellites | In French | → Environment, environmental sciences → Marine research, oceanography |
| MEO | Mid Earth Orbit | In English | → Astronomy |
| MEP | Main Engine Propellant | In English | |
| MESELSI | Mission Extension Shuttle Equipment Launch Site | In English | |
| MESELSI | Mission Extension Support Equipment Launch Site | In English | |
| MESSIAN | Methods for the efficient simulation of aircraft engine noise | In English | → Acoustics |
| MESSOC | Model Evaluation of Space Station Operations Cost | In English | → Prices |
| MEV | Mars Excursion Vehicle | In English | → Planets and satellites |
| MFA | Manned Flight Awareness | In English | |
| MFC | Multiple-Flight Computer | In English | → Hardware → Aeronautics, aircraft |
| MFC | Manual Flight Control | In English | → Aeronautics, aircraft |
| MFC | Multiple-Flight Controller | In English | → Aeronautics, aircraft |
| MFCS | Manual Flight Control System | In English | → Aeronautics, aircraft |
| MFF | MDM Flight Forward | In English | → Aeronautics, aircraft |
| MFP | Mission Flight Plan | In English | → Aeronautics, aircraft |
| MFPE | Mission From Planet Earth | In English | → Astronomy |
| MFR | Maximum Flight Rate | In English | → Aeronautics, aircraft |
| MFT | Mean Flight Time | In English | → Aeronautics, aircraft |
| MFTAD | Master Flight Test Assignment Document | In English | → Aeronautics, aircraft |
| MFTIO | Minimum Flyout Time For Orbital Interception | In English | |
| MHI | Mitsubishi Heavy Industries | In English | → Mechanical engineering |
| MIDSIM | Midcourse Exoatmospheric Event-Based Simulator | In English | → Astronomy |
| MILA | Merritt Island Launch Area | In English | |
| MILCOMSAT | Military Communications Satellite | In English | → Military engineering |
| MILSTAR | Military Strategic And Tactical Relay System | In English | → Military engineering |
| MIPS | Merritt Island Press Site | In English | → Newspapers, journalism |
| MIRV | Multiple Independently Targetable Reentry Vehicles | In English | |
| MisSp | Missiles Spacecraft | In English | → Serial publications, periodicals → Military engineering |
| MLC | Mobile Launcher Computer | In English | → Hardware |
| MLF | MDM Launch Forward | In English | |
| MLG | Main Landing Gear | In English | → Aeronautics, aircraft |
| MLGD | Main Landing Gear Door | In English | → Aeronautics, aircraft |
| MLGS | Microwave Landing Guidance System | In English | → Aeronautics, aircraft |
| MLP | Mobile Launch(er) Platform | In English | → Aeronautics, aircraft |
| MLS | Microwave Landing System | In English | → Aeronautics, aircraft |
| MLV | Medium-Lift Launch Vehicle | In English | → Aeronautics, aircraft |
| MLV | Medium Launch Vehicle | In English | → Aeronautics, aircraft |
| MLW | Maximum Landing Weight | In English | → Aeronautics, aircraft |
| MMLS | Martin Marietta Launch Services | In English | → Aeronautics, aircraft |
| MMS | Mission Modular Spacecraft | In English | |
| MMS | Multimission Spacecraft | In English | |
| MMS | Multimission Modular Spacecraft | In English | |
| MMS | Multi-mission Modular Spacecraft | In English | |
| MO | Manned Orbiter | In English | |
| MODE | Middeck Zero-Gravity Dynamics Experiment | In English | |
| MODS | Military Orbital Development System | In English | → Military engineering |
| MOF | Manned Orbital Flight | In English | |
| MOL | Manned Orbital Laboratory | In English | → Research institutes |
| MORL | Manned Orbiting Research Laboratory | In English | → Research institutes |
| MOSPO | Mobile Satellite Photometric Observatory | In English | → Observatories |
| MOSS | Manned Orbital Space Station | In English | |
| MPS | Materials Processing In Space | In English | → Materials science |
| MPS | Material Processing Satellite | In English | → Materials science |
| MPVA | Main Propellant Valve Actuator | In English | |
| MRSR | Mars Rover Sample Return | In English | → Planets and satellites |
| MS/MS | Material Science and Manufacturing in Space | In English | → Engineering, technology |
| MSBLS | Microwave Scan-Beam Landing System | In English | → Aeronautics, aircraft |
| MSDT | Multiple Shuttle Data Tape | In English | → Data |
| MSE | Manned Space Flight Engineer | In English | |
| MSF | Manned Space Flight | In English | |
| MSFC | Marshall Space Flight Center | In English | |
| MSFN | Manned Space Flight Network | In English | |
| MSFP | Manned Space Flight Program | In English | |
| MSFSG | Manned Space Flight Support Group | In English | |
| MSOB | Manned Spacecraft Operations Building | In English | |
| MSOCC | Multisatellite Operations Control Center | In English | |
| MSS | Medium/Small Satellite Servicing | In English | |
| MSSRV | Mars Surface-Sample Return Vehicle | In English | → Vehicle engineering |
| MSSTM | Military Space System Technology Model | In English | → Military engineering |
| MSSTP | Military Space Systems Technology Plan | In English | → Military engineering |
| MSVP | Master Shuttle Verification Plan | In English | |
| MT | Mission Trajectory | In English | |
| MTOGW | Maximum Takeoff Gross Weight | In English | → Aeronautics, aircraft |
| MTOW | Maximum Takeoff Weight | In English | → Aeronautics, aircraft |
| MTPE | Mission To Planet Earth | In English | → Planets and satellites |
| MUA | Maximum Usable Altitude | In English | → Aeronautics, aircraft |
| MŰI | Magyar Űrkutatási Iroda | In Hungarian | → Astronomy |
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