| N | Newton |
| N&G | navigation and guidance |
| N-S | Navier-Stokes |
| N/A | Nova interface adapter |
| N/A | next assembly |
| N/A | not applicable |
| N/B | narrow band |
| N/C | normally closed |
| N/C | nose cone |
| N/C | not critical |
| N/C | numerical control |
| N/C | numerically controlled |
| N/D | need date |
| N/FTS | near-/far-term system |
| N/L | no limit |
| N/O | normally open |
| N/P | not provided |
| N/R | not required |
| N/W | network |
| N/m2 | Newtons per meter squared |
| N2H2 | hydrazine |
| N2O4 | nitrogen tetroxide |
| NA | next action |
| NA | nodal architect |
| NA | not applicable |
| NA | numerical aperture |
| NAA | North American Aircraft |
| NAACP | National Association for the Advancement of Colored People |
| NAAL | North American Aerodynamic Laboratory (wind tunnel) |
| NAC | Naval Avionics Center |
| NAD | network adapter device |
| NAEC | Naval Air Engineering Center |
| NAM | National Association of Manufacturers |
| NAM | nuclear assessment methodology |
| NAP | navigation analysis program |
| NAR | numerical analysis research |
| NARS | National Archives and Record Services |
| NAS | National Academy of Sciences |
| NAS | national aircraft standard |
| NAS | national airspace system |
| NAS | naval air station |
| NAS | nonavionics simulator |
| NAS | numerical aerodynamic simulation |
| NASA | National Aeronautics and Space Administration |
| NASCOM | NASA communications (network) |
| NASDA | National Space Development Agency (Japan) |
| NASO | North American Space Operations |
| NASP | National AeroSpace Plane |
| NASTRAN | NASA structural analysis program |
| NAT | nonconformance action team |
| NATF | Naval Air Test Facility |
| NATO | North Atlantic Treaty Organization |
| NAUI | National Association of Underwater Instructors |
| NAVAID | navigation aid |
| NAVDAD | navigational derived air data |
| NAVEX | navigation expert |
| NAVPOOL | navigation parameter common pool |
| NAVSAT | navigation satellite |
| NAVSIM | autonomous navigation simulator |
| NAVT | NASA altimeter verification telemetry |
| NB | narrow band |
| NB | navigation base |
| NB | nitrogen base |
| NB | no bias (relay) |
| NBA | NSTS berthing adapter |
| NBA | narrow-band amplifier |
| NBDL | Naval Bio-Dynamics Laboratory |
| NBF | Neutral Buoyancy Facility |
| NBOSS | new-business operations support system |
| NBS | National Bureau of Standards |
| NBS | neutral buoyancy simulation |
| NBSAMRF | National Bureau of Standards Advanced Research Facility |
| NBT | neutral buoyancy trainer |
| NC | national course |
| NC | no change |
| NC | no comment |
| NC | noise criteria |
| NC | normal corrective |
| NC | normally closed |
| NC | numerical control |
| NC | numerically controlled |
| NC1 | nominal correction 1 (phasing maneuver) |
| NCA | National Command Authority |
| NCC | NASA Communications Control |
| NCC | NASA class code |
| NCC | NTB Control Center |
| NCC | Navstar Control Center |
| NCC | Network Control Center (GSFC) |
| NCC | nominal corrective combination (maneuver) |
| NCC | normal corrective combination (maneuver) |
| NCG | Nuclear Criteria Group |
| NCG | noncondensible gas |
| NCIU | network common interface unit |
| NCMC | NORAD Cheyenne Mountain Complex |
| NCO | numerically controlled oscillator |
| NCOS | National Commission on Space |
| NCR | no calibration required |
| NCR | nonconformance/failure report |
| NCS | network control station |
| NCS | nutation control system |
| NCSC | National Computer Security Center |
| NCU | nozzle control unit |
| ND | NASA document |
| ND | neutral density |
| ND | nondimensional |
| NDE | nondestructive evaluation |
| NDI | nondestructive inspection |
| NDRO | nondestructive readout |
| NDS | network distribution service |
| NDS | nuclear detection system |
| NDST | nondimensional special tool |
| NDT | nondestructive test |
| NDT | nondestructive testing |
| NDTF | nondestructive test facility |
| NDTL | nondestructive test laboratory |
| NDU | navigation data unit |
| NDUS | NUDET detection user segment |
| NDV | NASP-derived vehicle |
| NEA | noise equivalent angle |
| NEACP | National Emergency Airborne Command Post |
| NEAX | noise equivalent change in translation |
| NEC | national electrical code |
| NEEDS | NASA end-to-end data system |
| NEFD | noise equivalent flux density |
| NEI | noise equivalent irradiance |
| NEI | nonexplosive initiation |
| NELS | nuclear effects link simulator |
| NEMS | NASA equipment management system |
| NENU | nonexempt, nonunion |
| NEP | noise equivalent power |
| NEP | nominal entry point |
| NEP | normal entry point |
| NERVA | nuclear engine for rocket vehicle application |
| NES | network encryption system |
| NESC | national electrical safety code |
| NESP | Naval Extremely High Frequency Satellite Program |
| NESR | natural environment support room |
| NESS | National Environmental Satellite Service |
| NEST | nuclear emergency search team |
| NET | NASA employee team |
| NET | Nimbus Experiment team |
| NET | noise equivalent target |
| NET | noise equivalent temperature |
| NETCOM | network communications |
| NETSIM | network simulation |
| NEU | nonexempt, union |
| NEVADA | net energy verification and determination analyzer |
| NEVS | NASA equipment visibility system |
| NEWS | new engineering work schedule |
| NEWS | new engineering work system |
| NF | natural flood |
| NF | noise figure |
| NFLNA | noise figure low-noise amplifier |
| NFPA | National Fire Prevention Association |
| NFS | NASA FAR supplement |
| NFS | network file server |
| NFS | nozzle flow sensor |
| NFW | nonfuel-wasting |
| NG | narrow gauge |
| NG | nitrogen gauge |
| NG | nose gear |
| NGC | next-generation controller |
| NGS | NUDET ground system |
| NGT | NASA ground terminal |
| NH | nominal height (adjust maneuver) |
| NH | normal height (adjust maneuver) |
| NH&S | nuclear hardening and survivability |
| NH4 | hydrazine |
| NHA | next higher assembly |
| NHB | NASA Handbook |
| NHC | National Hurricane Center |
| NIB | noninterference basis |
| NIC | not in contract |
| NICE | Navstar interface control equipment |
| NIDS | network interface data system |
| NIM | nuclear instrumentation module |
| NIOSH | National Institute for Occupational Safety and Health |
| NIP | network input processor |
| NIP | network interface processor |
| NISS | national integrated scheduling system |
| NIU | network interface unit |
| NJP | network job processing |
| NL | no limit |
| NL | nose left |
| NLA | next lower assembly |
| NLD | Network Logistics Depot |
| NLG | nose landing gear |
| NLGD | nose landing gear door |
| NLM | nonlinear material |
| NLRB | National Labor Relations Board |
| NLT | not later than |
| NLT | not less than |
| NM | network manager (GSFC) |
| NM | nonmetallic |
| NMA | National Management Association |
| NMAB | National Materials Advisory Board |
| NMC | National Meteorological Center |
| NMCC | National Military Command Center |
| NMI | NASA management instruction |
| NMO | normal manual operation |
| NMOS | negative-type metal oxide semiconductor |
| NMR | nuclear magnetic resonance |
| NMT | not more than |
| NMT | notification of master tool |
| NMTA | National Metal Trades Association |
| NMTBA | National Machine Tool Builders' Association |
| NMTS | next manned transportation system |
| NMV | nitrogen manual valve |
| NNK | nonnuclear kill |
| NO | nitrous oxide |
| NO | normally open |
| NOAA | National Oceanic and Atmospheric Administration |
| NOC | network operation control |
| NOC | not otherwise coded |
| NOC | notation of content |
| NOCC | Network Operations Control Center (GSFC) |
| NOD | notice of discrepancy |
| NOES | National Operational Environmental Satellite |
| NOM | network output multiplexer |
| NOMOCALC | spectral nomographic calculator |
| NOP | normal operating procedure |
| NOPAR | non-OPPL part approval requests |
| NOPAR | nonorbiter parts authorization request |
| NOR | notice of revision |
| NORAD | North American Air Defense Command |
| NORDSAT | Scandinavian countries' broadcast satellite |
| NOS | network operating system |
| NOSL | night/day optical survey of thunderstorm lightning |
| NOSP | near-object scanning probe |
| NOSP | network operations support plan |
| NOSS | National Oceanic Satellite System |
| NOTS | Naval Ordnance Test Station |
| NP | navigation payload |
| NP | network program |
| NP | not provided |
| NPB | neutral particle beam |
| NPC | NASA procurement circular |
| NPC | NASA publication control |
| NPC | normal plane change |
| NPD | NASA policy directive |
| NPD | nominal percent defective |
| NPDS | nuclear particle detection subsystem |
| NPF | Navstar processing facility |
| NPG | naval proving ground |
| NPL | normal power level (see RPL) |
| NPN | NASA part number |
| NPRV | nitrogen pressure relief valve |
| NPS | NASA planning studies |
| NPS | nonpropulsive stage |
| NPSH | net positive suction head |
| NPSP | net positive static pressure |
| NPSP | net positive suction pressure |
| NPSS | NASA packet switching system |
| NPT | Navy pointer and tracker |
| NPU | nitrogen purge unit |
| NPV | nitrogen pressure valve |
| NR | noise rating |
| NR | nose right |
| NR | not required |
| NRALT | NASA radar altimeter |
| NRB | nuclear reactor/Brayton |
| NRC | National Research Council |
| NRC | Nitrosso rubber coating |
| NRC | nonrecurring costs |
| NRCC | National Research Council of Canada |
| NRD | National Range Division |
| NRDS | Nuclear Rocket Development Station (NASA) |
| NRFA | navigation radio frequency assembly |
| NRI | nonrecurring investment |
| NRL | Naval Research Laboratory |
| NRM | nonrecurring maintenance |
| NRP | normal rated power |
| NRS | nonconformance reporting system |
| NRT | near real time |
| NRTS | not repairable at this station |
| NRZ | nonreturn to zero |
| NRZ-L | nonreturn-to-zero level |
| NRZ-PSK | nonreturn-to-zero phase shift key |
| NRZ-TTL | nonreturn-to-zero transistor-transistor logic |
| NS | nickel steel |
| NS | not switchable |
| NS | nuclear Shuttle |
| NSA | National Security Agency |
| NSA | National Standards Association |
| NSA | nosewheel steering amplifier |
| NSACOR | National Security Agency Central Office of Record |
| NSAS | NSTS/SSPE attachment systems |
| NSC | NASA standard computer |
| NSC | Network Support Committee |
| NSC | navigational star catalog |
| NSC | nonstandard CA code |
| NSCCA | nuclear safety cross-check analysis |
| NSD | NASA standard detonator |
| NSE | nosewheel steering enable |
| NSHS | nosewheel steering hydraulic system |
| NSI | NASA standard initiator |
| NSI | network support item |
| NSI-I | NASA standard initiator Type I |
| NSIA | National Security Industrial Association |
| NSIF | Near-Space Instrumentation Facility |
| NSL | Northrop Space Laboratory |
| NSLD | NASA Shuttle Logistics Depot |
| NSM | network status monitor |
| NSN | national stock number |
| NSO | NASA support operation |
| NSP | NASA support plan |
| NSP | network signal processing |
| NSP | network signal processor |
| NSPAR | nonstandard part approval request |
| NSR | nominal slow rate |
| NSR | normal slow rate (maneuver) |
| NSR1 | first coelliptic maneuver |
| NSR2 | second coelliptic maneuver |
| NSS | network simulation system |
| NSSCC | NORAD Space Surveillance Computation Center |
| NSSDC | National Space Science Data Center |
| NSTI | NASA simulation traffic interface |
| NSTL | National Space Technology Laboratories (now John C. Stennis Space Center) |
| NSTS | National Space Transportation System |
| NSTSPO | NSTS Program Office |
| NSU | node switching unit |
| NSY | nonstandard Y code |
| NT&A | no test and ancillary |
| NTB | National Test Bed |
| NTBOS | NTB operating software |
| NTBSIM | NTB simulation |
| NTD | NASA test director |
| NTE | navigation telemetry encoder |
| NTF | National Test Facility |
| NTIS | National Technical Information Service |
| NTO | nitrogen tetroxide |
| NTO | nitrous oxide |
| NTP | network test panel |
| NTP | normal temperature and pressure |
| NTP | notice to proceed |
| NTS | navigation technology satellite |
| NTS | near-term schedule |
| NTS | nonavionics test station |
| NTS | not to scale |
| NTSO | NASA Test Support Office |
| NTSS | nitrogen transfer and storage system |
| NTTF | network test and training facility |
| NUDET | nuclear detonation |
| NUL | non-GSE utilization list |
| NUTI | NASCOM user traffic interface |
| NV | NASA altimeter verification |
| NV | nuclear vehicle |
| NVAFB | North Vandenberg Air Force Base |
| NVE | nonvisual eyepiece |
| NVEOL | Night Vision and Electro-Optical Laboratory |
| NVM | nonvolatile memory |
| NVR | NASA waiver |
| NVR | no verification required |
| NVR | no voltage release |
| NVR | nonvolatile residue |
| NW | nosewheel |
| NWE | nuclear weapons effect |
| NWG | natural work group |
| NWMP | nuclear weapons monitor plan |
| NWS | National Weather Service |
| NWS | nosewheel steering |
| NWSA | nosewheel steering amplifier |
| NWT | nonwatertight |
| NWU | north, west, up |
| NWW | nosewheel well |
| NX | normal to X-axis |
| NX | nose to X-axis |
| NY | normal to Y-axis |
| NY | nose to Y-axis |
| NZ | normal acceleration |
| NZ | normal load factor (g) |
| NZ | normal to Z-axis |
| NZ | nose to Z-axis |
| NZB | nonzero binary |
| Nd:YAG | neodymium:yttrium aluminum garnet |
| n | neutron |
| nm | nanometer |
| nmi | nautical mile |
| ns | nanosecond |