| ac |
Alternating current |
| ACCEL |
Accelerometer or acceleration |
| ACE |
Acceptance checkout equipment |
| ACK |
Acknowledge |
| ACP |
Audio control panel |
| ACS |
Attitude control subsystem |
| A/D |
Analog to digital |
| AGC |
Automatic: gain control |
| AGE |
Aerospace ground equipment |
| AH |
Ampere hour |
| ALT |
Altitude |
| AM |
Amplitude modulation or ammeter |
| AMPL |
Amplifier |
| ANL |
Analog |
| AOA |
Angle of attack |
| ARS |
Attitude reference subsystem |
| ASCP |
Attitude set control panel |
| ASI |
Apollo standard initiator |
| ATT |
Attitude or attenuator |
| AUTO |
Automatic |
| AUX |
Auxiliary |
| AVC |
Automatic volume control |
| BAT |
Battery |
| BCD |
Binary coded decimal |
| BCN |
Beacon |
| BECO |
Booster engine cutoff |
| BMAG |
Body-mounted attitude gyro |
| BPC |
Boost protective cover |
| bps |
Bits per second |
| BTU |
British thermal unit |
| BU |
Backup |
| BUR |
Backup rate |
| CB |
Circuit breaker |
| CCFT |
Controlled current feedback transformer |
| CCTV |
Closed-circuit television |
| CCW |
Counter-clockwise |
| C&D |
Controls and displays |
| CDF |
Confined detonating fuse |
| cfm |
Cubic feet per minute |
| CG |
Center of gravity |
| CHAN |
Channel |
| CAT |
Circuit |
| CL |
Centerline |
| CLM |
Core logic module |
| CM |
Command module |
| CMC |
Command module computer |
| CMD |
Command |
| C/O |
Checkout |
| CO2 |
Carbon dioxide |
| COAS |
Crew optical alignment sight |
| COAX |
Coaxial |
| COI |
Contingency orbit insertion |
| COMM |
Communications |
| COMPR |
Compressor |
| COMPEN |
Compensator |
| COND |
Condenser or conditioner |
| CONT |
Control |
| CPLR |
Coupler |
| CPS |
Cycles per second |
| CRYO |
Cryogenic |
| CSC |
Cosecant computing amplifier |
| CSM |
Command and service modules |
| CSS |
Computer subsystem |
| C&W |
Caution and warning subsystem |
| CW |
Clockwise or continuous wave |
| CTE |
Central timing equipment |
| CWG |
Constant wear garment |
| D/A |
DigitaI to anaIog |
| DAC |
Digital-to-analog converter |
| DAP |
Digital autopilot |
| DB |
Deadband |
| db |
Decibel |
| dc |
Direct current |
| DEG |
Degree |
| DECR |
Decrease |
| DELTA/P |
Differential pressure |
| DELTA/V |
Differential velocity |
| DEMOD |
Demodulate |
| DET |
Detector or digital event timer |
| DISCR |
Discriminator |
| DRI |
Data rate indicator |
| DSE |
Data storage equipment |
| DSIF |
Deep Space Instrumentation Facility |
| DSKY |
Display and keyboard |
| E |
Elevation angle |
| ECA |
Electronic control assembly |
| ECO |
Engine combustion or engine cut |
| ECS |
Environmental control subsystem |
| ECU |
Environmental control unit |
| EDA |
Electronic display assembly |
| EDS |
Emergency detection subsystem |
| ELECT |
Electronic |
| ELS |
Earth landing subsystem |
| ELSC |
Earth landing sequence controller |
| EMER |
Emergency |
| EMI |
Electromagnetic interference |
| EMS |
Entry monitor subsystem |
| EMU |
Extravehicular mobility unit |
| ENC |
Encode |
| ENG |
Engine |
| EOS |
Emergency oxygen system |
| E&PL |
Entry & post-landing |
| EPS |
Electrical power subsystem |
| ERR |
Error |
| ETR |
Eastern test range |
| EU |
Electronic unit |
| EVA |
Extravehicular activity |
| FC |
Fuel cell |
| fc |
Center frequency |
| FCSM |
Flight combustion stability monitor |
| FDAI |
Flight director attitude indicator |
| FDT |
Full duplex teletype circuit |
| F /F |
Flip-flop |
| FHS |
Forward heat shield |
| FLT |
Flight |
| FLSC |
Flexible linear shaped charge |
| FM |
Frequency modulation |
| FOV |
Field of vision |
| CQR |
Flight qualification recorder |
| fs |
Full scale |
| FSK |
Frequency shift-keyed |
| FWD |
Forward |
| G |
Gravity |
| GA |
Gyro assembly |
| gc |
Gigacycles |
| G&C |
Guidance and control |
| GDC |
Gyro display coupler |
| GET |
Ground elapsed time |
| GFE |
Government-furnished equipment |
| GMBL |
Gimbal |
| GN2 |
Gaseous nitrogen |
| GND |
Ground |
| GNCS |
Guidance, navigation, and control subsystem |
| GPI |
Gimbal position indicator |
| GSE |
Ground support equipment |
| GSFC |
Goddard Space Flight Center |
| ha |
Apogee altitude |
| H2 |
Hydrogen |
| He |
Helium |
| HF |
High frequency |
| Hg |
Mercury |
| HGA |
High-gain antenna |
| HI |
High |
| hp |
Perigee altitude |
| HR |
Hydrogen relief or hour |
| HTR |
Heater |
| Hz |
Hertz (cycle per second) |
| IC |
Intercom |
| ICDU |
Inertial coupling data unit |
| IECO |
inboard engine cutoff |
| IF |
Intermediate frequency |
| IFM |
In-flight maintenance |
| IGA |
Inner gimbal angle |
| IGN |
Ignition |
| IMP |
Impulse |
| IMU |
Inertial measurement unit |
| INCR |
Increase |
| IND |
Indicator |
| INV |
Inverter |
| IPB |
Illuminated push button |
| IPS |
Instrumentation power subsystem or inches per second |
| IRIG |
Inertial rate integrating gyro |
| ISOL |
Isolation |
| ISS |
Inertial subsystem |
| IU |
Instrument unit |
| JETT |
Jettison |
| kbs |
Kilobits per second |
| kc |
Kilocycles |
| kHz |
Kilohertz |
| KOH |
Potassium hydroxide |
| KSC |
Kennedy Space Center |
| kw |
Kilowatt |
| LAT |
Latitude |
| LCC |
Launch Control Center |
| LDEC |
Lunar docking events controller |
| LEA |
Launch escape assembly |
| LEB |
Lower equipment bay |
| LEM |
Lunar excursion module, old name for lunar module) |
| LES |
Launch escape subsystem |
| LET |
Launch escape tower |
| LEV |
Launch escape vehicle |
| LF |
Low frequency |
| LH2 |
Liquid hydrogen |
| LHEB |
Left-hand equipment bay |
| LHFEB |
Left-hand forward equipment bay |
| LM |
Lunar module |
| LMK |
Landmark |
| LO |
Low |
| LOR |
Lunar orbit rendezvous |
| LOS |
Line of sight, loss of signal |
| LOX |
Liquid oxygen |
| LSB |
Lower sideband |
| LSC |
Linear-shaped charge |
| LSSC |
LM separation sequence controller |
| LV |
Launch vehicle or lift vector |
| MAN |
Manual or manifold |
| MAX |
Maximum |
| MAXQ |
Maximum dynamic pressure |
| MCC |
Mission Control Center |
| MDC |
Main display console |
| MDF |
Mild detonating fuse |
| MED |
Medium |
| MESC |
Master events sequence controller |
| MGA |
Middle gimbal angle |
| mHz |
Mega Hertz |
| MIKE |
Microphone |
| mil |
1/1000 |
| MIN |
Minimum |
| ML |
Moldline |
| MMH |
Monomethylhydrazine |
| MNA |
Main bus A |
| MNB |
Main bus B |
| MOD |
Modulator |
| MOT |
Motor |
| MS |
Motor switch |
| MSC |
Manned Spacecraft Center |
| MSFC |
Marshall Space Flight Center |
| MSFN |
Manned Space Flight Network |
| MTVC |
Manned thrust vector control |
| mv |
Millivolt |
| mw |
Milliwatt |
| N2 |
Nitrogen |
| NAV |
Navigation |
| NB |
Navigation base or narrow band |
| NEG |
Negative |
| NEUT |
Neutral |
| n.mi. |
Nautical mile |
| NO. |
Number |
| N.O. |
Normally open |
| NON-ESS |
Non-essential |
| NORM |
Normal |
| NRZ |
Non-return to zero |
| NSIF |
Near-Space Instrumentation Facility |
| O2 |
Oxygen |
| OCDU |
Optics coupling data unit |
| OECO |
Outboard engine cutoff |
| OGA |
Outer gimbal angle |
| OH |
Hydroxyl ion |
| O/L-RC |
Overload - reverse current |
| OMNI |
Omni-directional |
| OPT |
Optics |
| OR |
Oxygen relief |
| ORDEAL |
Orbit rate drive electronics Apollo LM |
| OSC |
Oscillator |
| OSS |
Optics subsystem |
| O/V |
Overvoltage |
| OXID |
Oxidizer |
| PA |
Power amplifier |
| PAM |
Pulse amplitude modulation |
| PB |
Push button |
| PCM |
Pulse code modulation or pitch control motor |
| PCVB |
Pyro continuity verification box |
| PDM |
Pulse duration modulation |
| PF |
Pulse frequency or powered flight |
| PGA |
Pressure garment assembly |
| PH |
Phase |
| pH |
Hydrogen ion concentration |
| PIPA |
Pulsed integrating pendulous accelerometer |
| PLBK |
Playback |
| PLSS |
Portable life support system |
| PM |
Phase modulation |
| PMP |
Premodulation processor |
| POS |
Positive |
| POT |
Potentiometer |
| PPM |
Parts per million or pulse position modulation |
| PPS |
Pulses per second |
| PRF |
Pulse repetition frequency |
| PRI |
Primary |
| PRN |
Pseudo-random noise |
| PROP |
Propellant |
| PS |
Pressure switch |
| PSA |
Power servo assembly |
| PSI |
Pounds per square inch |
| PSIA |
Pounds per square inch absolute |
| PSIG |
Pounds per square inch gauge |
| PSK |
Phase shift-keyed |
| PSO |
Pad safety officer |
| PTT |
Push to talk |
| PU |
Propellant utilization |
| PUG |
Propellant utilization gauging |
| PWR |
Power |
| PYRO |
Pyrotechnic |
| R |
Range |
| RAD |
Radiation dosage or radiator |
| RC |
Rotation control or range command |
| RCDR |
Recorder |
| RCS |
Reaction control subsystem |
| RCSC |
Reaction control subsystem controller |
| RCV |
Receive |
| RCVR |
Receiver |
| RECO |
Rough engine cutoff |
| RECT |
Rectifier |
| R&D |
Research and development |
| REG |
Regulator |
| REGEN |
Regenerator |
| REL |
Release |
| REV |
Reverse |
| RF |
Radio frequency |
| RFI |
Radio frequency interference |
| RGA |
Rate gyro assembly |
| RHC |
Rotation hand control |
| RHEB |
Right-hand equipment bay |
| RHFEB |
Right-hand forward equipment bay |
| RJD |
Reaction jet driver |
| RJ/EC |
Reaction jet and engine control |
| RMS |
Root mean square |
| RNG |
Range |
| RNDZ |
Rendezvous |
| ROT |
Rotation |
| RT |
Rendezvous radar transponder |
| RSI |
Roll stability indicator |
| RSO |
Range safety officer |
| RTC |
Real-time command |
| RTV |
Real-time television |
| RUPT |
Interrupt |
| RZ |
Return to zero |
| S/C |
Spacecraft |
| SCE |
Signal conditioning equipment |
| SCI |
Scientific |
| SCO |
Subcarrier oscillator |
| SCS |
Stabilization and control subsystem |
| SCT |
Scanning telescope |
| SEC |
Second or secondary |
| SECO |
S-IVB (third stage) engine cutoff |
| SECS |
Sequential events control subsystem |
| SENS |
Sensitivity |
| SEP |
Separation or spacecraft electronic package |
| SEQ |
Sequencer |
| SIG |
Signal |
| SLA |
Spacecraft-LM adapter |
| SLOS |
Star line of sight |
| SM |
Service module |
| SMJC |
Service module jettison controller |
| SNSR |
Sensor |
| SOV |
Shutoff valve |
| SPEC |
Specification |
| SPS |
Service propulsion subsystem or samples per second |
| SSB |
Single sideband |
| STBY |
Standby |
| SW |
Switch |
| SXT |
Sextant |
| SYNC |
Synchronization |
| TB |
Talkback indicator |
| TC |
Translation control |
| T/C |
Telecommunications subsystem |
| T/D |
Time delay |
| TEC |
Transearth coast |
| TEI |
Transearth injection |
| TEMP |
Temperature |
| TFL |
Time from launch |
| THC |
Translation hand control |
| TIGN |
Time of ignition |
| TJM |
Tower jettison motor |
| TLC |
Translunar coast |
| TLI |
Translunar injection |
| TLM |
Telemetry |
| TMG |
Thermal meteoroid garment |
| TPAC |
Telescope precision angle counter |
| T/R |
Transmit-receive |
| TRNFR |
Transfer |
| TTE |
Time to event |
| TV |
Thrust vector or television |
| TVC |
Thrust vector control |
| TVSA |
Thrust vector position servo amplifier |
| TWR |
Tower |
| TWT |
Traveling wave tube |
| UCD |
Urine collection device |
| UDL |
Up-data link |
| UDMH |
Unsymmetrical dimethyl hydrazine |
| UHF |
Ultra high frequency |
| UPTL |
Up-link telemetry |
| USBE |
Unified S-band equipment |
| U/V |
Undervoltage |
| V |
Voice, volt, or velocity |
| VAC |
Volts alternating current |
| Vc |
Circular velocity |
| VCO |
Voltage-controlled oscillator |
| VDC |
Volts direct current |
| VGP |
Vehicle ground point |
| VHF |
Very high frequency |
| VHF/AM |
Very high frequency/audio modulated |
| VM |
Voltmeter or measured velocity |
| VO |
Initial velocity |
| VOL |
Volume |
| VOX |
Voice-operated relay |
| VSWR |
Voltage standing wave ratio |
| W/G |
Water-glycol |
| WMS |
Waste management system |
| WPM |
Words per minute |
| WTR |
Western test range |
| XC |
Command module station |
| XCVR |
Transceiver |
| XDUCER |
Transducer |
| XFMR |
Transformer |
| XMIT |
Transmit |
| XMTR |
Transmitter |
| XPONDER |
Transponder |
| XS |
Service module station |
| ZN |
Zinc |