Abbreviation   Description
ACE   Advanced Composition Explorer Spacecraft
ACRS   Automated Conflict Resolution System
ACS   Assembly/Contingency Subsystem
ACU   Antenna Control Unit
AFSCN   Air Force Satellite Control Network
AGU   American Geophysical Union
AHS   American Helicopter Society
AIAA   American Institute of Aeronautics and Astronautics
ALS   Advanced Launch System
ALS   Advanced Life Support
ALSARM   Advanced Life Support Automated Robotic Mechanism
AMDS   Automatic Message Distribution System
AMS   American Mathematical Society
AMS   American Meteorological Society
AN   Ascending Node
ANS   ATM Network Switches
ANTD   Antenna down, artificial mission
ANTUTIL   Antenna Utilization Analysis Program
AOBD   Acousto-Optic Beam Deflector
AOS   Acquisition Of Signal
APCU   Auxiliary Power Converter Unit
APS   Alternate Payload Specialist
APTMS   Advanced Payload Transfer Guidance System
ARC   Ames Research Center
ARD   Atmospheric Reentry Demonstration
ARIS   Active Rack Isolation System
ASC   American Society for Composites
ASCE   Airlock Signal Conditioning Electronics
ASCN   Ascension Tracking Station
ASDL   Advanced Systems Development Laboratory
ASI   Agenzia Spazile Italiana
ASM   American Society of Metals
ASME   American Society of Mechanical Engineers
ASP   Attached Shuttle Payload
ASTER   Advanced Spaceborne Thermal Emission Radiometer
ASTM   American Society for Testing and Materials
ASTP   Advanced Space Transportation Program
ASTT   Aeronautics and Space Transportation Technology
ATDnet   Advanced Technology Demonstration Network
ATE   automated test equipment
ATM   Asynchronous Transmission Method or Asynchronous Transfer Mode
ATP   Acceptance Test Plan
ATPS   Automatic Tile Processing Navigation System
ATSC   AlliedSignal Technical Services Corporation
AURIO   Auroral Imaging Observatory
AWID   Automated Window Inspection Device
AXAF   Advanced X-ray Astrophysics Facility
Az-El   Azimuth-Elevation
BCR   Body Centered Rotating
BDA   Bermuda
BPC   Biomass Production Chamber
BRTS   Bilateral Ranging Transponder System
BTTS   Bilateration Transponder Telemetry Subsystem
CA   Coverage Analysis
CAB   Circuit Assurance Block
CAD   computer-aided design
CAS   Coverage Analysis System
CASE   Confined Access Support Equipment
CB   C-Band frequency
CC   Configuration Control
CCAS   Cape Canaveral Air Station
CCB   Configuration Control Board
CCD   Charged Coupled Device
CCF   Converter Compressor Facility
CCR   Configuration Control Request
CCS   Communication and Control Segment
CCTV   Closed Circuit Television
CDA   Command and Data Acquisition
C&DH   Command and Data Handling
CDR   Commander
CDR   critical design review
CED   Coverage Event Data
CEEK   Cargo Element Extension Kit
CELSS   Controlled Ecological Life Support System
CEWS   cargo element workstand
CF   Cost Feasibility
CF   Construction of Facilities
CFC   chlorofluorocarbon
CG   Center Of Gravity
CG   Cloud to Ground
CGC   cold gas compression
CGRO   Compton Gamma Ray Observatory
CHEK   Cargo Handling Equipment Kit
CIC   Crew Interface Coordinator
CIC   Combat Information Center
CLASS   Communications Link Analysis and Simulation System
CLCS   Checkout and Launch Control System
CLIM   Cable Line Inspection Mechanism
CLP   Configuration Loading Parameters
CM   Configuration Manager
CM   Coverage Model
CM   Configuration Management
CMB   Configuration Management Board
CMB   Combined Mission - Mission Satisfaction Database
CMD   Command
CMS   Coverage Management System
CMS   Coordinate Measurement System
CNF   K-band and S-band on same physical antenna option
CNMOS   Consolidated Network Mission and Operations Support
CO2   carbon dioxide
COD   Coverage Database
COPUOS   United Nations Committee on the Peaceful Uses of Outer Space
COSPAR   Committee on Space Research
COTS   Commercial Off-The-Shelf
CRB   Change Review Board
CRCA   component refurbishment chemical analysis
CSA   Canadian Space Agency
CSES   Center for the Study of Earth from Space (Univ of Colorado)
C&TCS   Communications and Tracking Checkout System direct current
CTFS   Common Time and Frequency System
CTV   Compatibility Test Van
CTV   Crew Transfer Vehicle
CUE   Common User Element
CV   Coverage Variability
DAB   Demand Access Buffer
DAC   Design Analysis Cycle
DAS   Direct Access SAAIF (Interface File)
DAS   Demand Access System
DAT   Demand Access Technology
DAU   Data Archive Utility
DB   Database
DBMS   Database Management System
DBR   Database Report
DBSI   Direct Broadcasting System Inc.
DCI   Doppler Compensation Inhibit
DCN   Document Change Notice
DCR   design certification review
DE   Detailed Event
DEAP   Dryden Early Access Platform
DFRC   Dryden Flight Research Center
DLT   Data Link Terminal
DMES   dimethylethoxysilane
DMR   Detailed Mission Requirements
DMSP   Defense Meteorological Satellite Program
DN   Descending Node
DoD   Department Of Defense
DOF   degree of freedom
DRF   clock drift
DR   Discrepancy Report
DRR   data review room
DRT   Disaster Recovery Terminal
DSM   Dutonium 236 Space Modulator
DSN   Deep Space Network
DSP   Digital Signal Processing
DTL   Development Test Laboratory
DTV   digital television
DVCS   Digital Voice Communication System
Ebnet   EOSDIS Backbone Network
EC   Engineering Change
ECIN   Expert Center for Intracenter Networking
ECOMM   early communications
ECU   Environmental Control Unit
EDC   Engineering Documentation Center
EDD   Engineering Development Directorate
EE   end-effector
EELV   Evolved Expendable Launch Vehicle
EET   End to End Test
EIRP   Effective Isotropic Radiated Power
ELV   Expendable Launch Vehicle
EMC   electromagnetic control
ENTTOT   MM Entry Scheduling Results Report
EO-ICWG   Earth Observations International Coordination Working Group
EOS   Earth Observing System
EOSDIS   EOS Data and Information System
EOV   End Of Visibility
EPGS   EOS Polar Ground Stations
EPHGEN   Ephemeris Generator Program
EPMFC   Earth Potential for Manned Flight Computation
EQM   Copy function, Equal Mission option
ERBS   Earth Radiation Budget Satellite
ERSMK   Element Rotation Stand Modification Kit
ESA   European Space Agency
ESSC   Earth System Sciences Committee
ET   External Tank
ETS   Engineering Test Satellite
EUMETSAT   European Organization for the Exploitation of Meteorological Satellites
FAA   Federal Aviation Administration
FAMU   Florida A & M University
FAR   Faculty Awards for Research
FCC   Federal Communications Commission
F/C   Flight Controller
FD   Flight Director
FDD   Functional Design Document
FDDI   Fiber Distributed Data Interface
FGSE   fluid ground support equipment
FITS   Flexible Image Transport System (standard for file structure)
FNBIC   Florida/NASA Business Incubation Center
FM   Flight Model
FOC   Faint Object Camera
FOT   Final Observation Tape (delivered by the SDC)
FOV   Field Of View
FPGA   Field Programmable Gate Array
FRD   Functional Requirement Document
FRED   Fast Retrieval Enterprise Data
FRF   flight readiness firing
FRR   Functional Requirement Review
FRR   Flight Readiness Review
FSU   Florida State University
FTIR   Fourier Transform Infrared
FTP   File Transfer Protocol
FTXS   FDDI Transmission System
GARF   Goddard Antenna Research Facility
GCP   Goddard Corporate Park
GDC   General Data Corporation
GDIS   Guam Data Interface System
GEM   Goddard Earth Model
GET   Ground Elapsed Time
GH2   Gaseous hydrogen
GH   gaseous helium
GIM   Ground Interface Module
GISS   Goddard Institute for Space Studies
GLA   Goddard Laboratory for Atmospheres
GLS   Ground Launch Sequencer
GLTS   Gas Leakage Test Stand
GMS   ground measurement system
GN2   gaseous nitrogen
GN   Ground Network
GO   Geometric Optimization
GO   Guest Observer
GOES   Geostationary Operational Environmental Satellite
GOX   gaseous oxygen
GRGT   Guam Remote Ground Terminal
GRO   Compton Gamma Ray Observatory
GSA   General Support Agreement
GSDE   Ground Support Design Engineering
GSE   ground support equipment
GSFC   Goddard Space Flight Center
GSMASK   GN Geodesics and Mask
GSMST   Ground System Mission Simulation Tester
GSPN   Ground Systems Pneumatics
GSRP   Graduate Student Research Program
GSTDN   Ground Spaceflight Tracking and Data Network
GTDS   Goddard Trajectory Determination System
GTI   Good Time Interval (used for selecting time periods)
GUI   Graphical User Interface
HAK   Hatch Access Kit
HAS   Hatch Access Structure
HCI   Human Computer Interface
HDTV   High Definition Television
HEA   High Energy Astrophysics
HEAD   HEA Data-handling
HEDS   Human Exploration and Development of Space
HEPA   High Efficiency Particle Accumulator
HFIS   HEPA Filter Inspection System
HGA   High Gain Antenna
HITM   Hole In The Mirror
HK   Housekeeping
HMF   Hypergol Maintenance Facility
HORP   Height Of Ray Path
HP   horsepower
HST   Hubble Space Telescope
HTML   HyperText Markup Language
HVAC   heating, ventilating, and air conditioning
Hz   hertz
IADC   Inter-Agency Space Debris Coordination Committee
I-Channel   In-phase Channel
ICD   Interface Control Document
ICE   Intelligent Component Expert
ICM   Interim Control Module
ICSU   International Council of Scientific Unions
ICWG   International Coordination Working Group
ID   Identifier
IEA   Integrated Electronics Assembly
IEEE   Institute of Electrical and Electronic Engineers
IFAS   Intelligent Fracture Analysis System
IFC   In-Flight Calibration (uses Radiation Sources)
IFL   Intra Facility Link
INWG   Internet Network Working Group
IP   Internet Protocol
IP   International Partner of ISS
IPT   Integrated Products Team
IR   infrared, Isolation Router
IRA   Institute Research Awards
ISDN   Integrated Services Digital Network
ISO   International Organization of Standards
ISPR   International Standard Payload Rack
ISS   International Space Station
ISTP   International Solar Terrestrial Physics Program
IT   Information Technology
IUS   Inertial Upper Stage
IVHM   Integrated Vehicle Health Monitoring
JGOAL   Java PCGOAL
JJ   Biomedical Operations Office
JMICB   Joint Management Integrated Control Board
JSC   Johnson Space Center
JPL   Jet Propulsion Laboratory
KHB   Kennedy handbook
KSA   K-band Single Access
KSA-F   K-band Single Access - Forward
KSA-R   K-band Single Access - Return
KSC   John F. Kennedy Space Center
KSDN   Kennedy Switched Data Network
L - 1   Launch Minus 1 Year
L - 2   Launch Minus 2 Years.
LAN   Local Area Network
LaRC   Langley Research Center
LC   launch complex
LC - 17   Launch Complex 17
LC - 36   Launch Complex 36
LC - 39   Launch Complex 39
LCC   Launch Control Center
LCCA   Lead Center for Communications Architecture
LCS   Launch Control System
LDBP   Long Duration Balloon Project
LeRC   Lewis Research Center
LES   Launch Equipment Shop
LETF   Launch Equipment Test Facility
LFBB   Liquid Fly-Back Booster
LH2   liquid hydrogen
LH   liquid helium
LINK   link ID
LMLV   Lockheed Martin Launch Vehicle (renamed Athena)
LMSW   Lockheed Martin Skunk Works
LMT   local mean time
LN2   liquid nitrogen
LNA   Low Noise Amplifier
LO2   liquid oxygen
LOP   Local Operating Procedures
LOS   Loss Of Signal
LOX   liquid oxygen
LPIS   Launch Package Integration Stand
LPS   launch processing system
LSAT   Land Satellite
LST   Local Solar Time
LSU   Louisiana State University
MA   Mean Anomaly
MA   Multiple Access (Link/Antenna - TDRSS)
MABE   MA Beamforming Equipment
MACE   MPLM access certification equipment
MACS   Mobile Automated Cleaning System
MA-F   Multiple Access - Forward
MA-R   Multiple Access - Return
MAF   multiple access forward
MAR   multiple access return
MAXC   Maximum prime service length
MAXEL   Maximum Elevation
MAXS   Maximum count or time per schedule period
MAXSEP   Maximum separation time
MBPS   MegaBits Per Second
MBR   MILA Bermuda Re-engineering
MCSA   motor current signature analysis
MD   Mission Director
ME   Mission Effectiveness
MEIT   Multi-Element Integrated Test
MG&SR   Mission Generic and Specific Requirements
MGS   McMurdo Ground Station
MI   mutual interference
MID   Mission Integration Document
MIL   Merritt Island, Florida
MILA   Merritt Island Launch Area
MINC   Minimum prime service length
MINS   Minimum count or time per schedule period
MINSEP   Minimum separation time
MIPS   Million Instructions Per Second
MLI   multilayer insulation
MLP   Mobile Launcher Platform
MM   Mission Model
MOC   Mission Operations Center
M&P   Materials and Processes
MPH   miles per hour
MPLM   Mini-Pressurized Logistics Module
MPO   Mission Priority Order
MPS   Main Propulsion System
MRR   Mission Requirements Request
MS   Mission Specialist
MSBLS   Microwave Scanning Beam Landing System
MSCI   Mission Scientist
MSD   Materials Science Division
MSFC   Marshall Space Flight Center
MSFN   Manned Space Flight Network
MSPTA   Mission Schedule Period Totals Array
MSR   Mission Status Report
MSR   Mission Support Requirements
MSS   Message Switching System
MSU   Mission Service Utilization
MTDE   Mission to Planet Earth
MTRS   McMurdo TDRSS Relay System
NAK   Node Access Kit
N&MS   Networks and Mission Services
N&MSP   Networks and Mission Services Project
NAM   Network Advisory Message
NAS   National Academy of Sciences
NASA   National Aeronautics and Space Administration
NASCOM   NASA Communications Network
NASDA   National Space Development Agency of Japan
NAU   Network Analysis Unit
NCAR   National Center for Atmospheric Research
NCC   Network Control Center
NCCDS   NCC Data System
NCCS   NASA Center for Computational Sciences
NCD   Nascom Circuit Directory
NCS   National Communication System
NDE   nondestructive evaluation
NDS   Network Documentation System
NEC   Network Equipment Configuration
NFI   Narrow Field Instrument (any of LECS, MECS, HP-GSPS and PDS)
NIA   Network Integration and Analysis
NIC   Network Interface Card
NILE   Network Integration Lab Environment
NM   Network Model
NMOS   Network Mission Operations Support Contract
NOAA   National Oceanic and Atmospheric Administration
NP   Nominal Pointing
NPI   Nominal Pointing Interval
NPAS   Network Planning and Analysis System
NPG   Network Protocol Gateway
NRC   Nuclear Regulatory Commission
NSCN   Navy Satellite Control Network
NSIDC   National Snow and Ice Data Center
NSL   Network Space Load
NSTS   National Space Transportation System
NTIA   National Telecommunications and Information Agency
NTM   NeTwork Model
NTRD   Nascom Traffic Requirements Database
NTS   NCC Test System
OBC   On Board Computer
OBT   On-Board Time
O&C   Operation and Checkout
OCC   Operations Control Centre (utilizes satellite links)
OCR   Operational Control Room
OD   operational downlink (Shuttle telemetry)
OIS-D   Operational Intercommunications System - Digital
OJT   on-the-job training
OMI   Orbital Maneuvering Subsystem
OP   Observing Period (consisting of one or more observations)
OPC   Organic Photo Conducting
OPF   Orbiter Processing Facility
ORU   Orbital replaceable unit
OSC   Orbital Sciences Corporation
OSF   Office of Space Flight
OSPF   Open Shortest Path First
OSS   Office of Space Science
OTV   operational television
OV   Orbiter Vehicle
PA   Performance Analysts
PACE   Prelaunch Automatic Checkout Equipment
PACER   Purpose, Agenda, Code of Conduct, Expectations/Introductions, and Roles
PAMS   Portable AFT Mass Spectrometer
PAN   Physical Association Number
PAP   Program Advanced Planning
PAS   Payload Attach System
PAWS   Paging and Area Warning System
PBL   planetary boundary layer
PCIS   Project Control Information System
PCR   Payload Changeout Room
PDR   Preliminary Design Review
PDSCWFRS   Parabolic Dish Solar Collector Waste Fluid Reduction System
PDSS   Payload Data Services System
PE   Prototype Event
PGOC   Payload Ground Operations Contractor
PHSF   Payload Hazardous Servicing Facility
PI   Principle Investigator
PIH   Payload Integration Hardware
PIPS   Payload Inspection and Processing System
PLAK   PLM Late Access Kit
PLAP   PCR Late Access Platform
PLM   Pressurized Logistics Module
PLT   Pilot
PM   Preventative Maintenance
PMA   Pressurized Mating Adapter
PML   Production Measurement Log
PMS   Permanent Measurement System
PMMO   Projects and Missions Management Office
PMT   Program Management Team
PN   Pseudorandom Noise
POCC   Payload Operations Control Center; Project Operations Control Center
POCS   Photo Optical Control System
POIC   Payload Operations Integration Center
POD   Payload Operations Director
POEMS   Positron Electron Magnetic Spectrometer
POGO   Polar-Orbiting Geophysical Observatory
POLES   Polar Exchange at the Sea Surface
POP   Program Operating Plan
PRACA   Problem Reporting and Corrective Action
PROS   Post Reduction Off-line Software
PS   Payload Specialist
PSAT   Predicted Site Acquisition Table
PSI   pound per square inch
PSIG   pound per square inch gage
PSLV   Polar Satellite Launch Vehicle
PTCS   Payload Test and Checkout System
PTP   Programmable Telemetry Processor
PVM   Performance Verification Matrix
Q Channel   Quadrature Channel
QA   Quality Assurance
QM   Qualification Model
QD   quick disconnect
RAAN   Right Ascension of Ascending Node
RAP   Report Analysis Program
RAS   Rack Access Stands
RASCAL   Reflective Aberration Simulator for Calibration
RCCA   Root Cause and Corrective Action
R&D   Research and Development
RDDC   Rack Drawer Delivery Cart
RDH   Rack Drawer Handler
REAP   Removable End Access Platform
RER   Ranging Exciter Receiver
RF   Radio Frequency
RFI   Radio Frequency Interference
RID   rack insertion device
RIS   Reflector In Space
RLA   Random Loading Analysis
RLV   Reusable Launch Vehicle
RMAS   Remote Monitor and Alarm System
RME   Risk Mitigation Experiment
RMM   Realtime Mission Manager
RNG   Ranging
ROAP   Removable Overhead Access Platform
RPLOT   Resource Plot
RSA   Russian Space Agency
RS&H   Reynolds, Smith & Hill, Inc.
RSP   Responsible Person
RSRM   Redesigned Solid Rocket Motor
RT   Real Time
RTI   Research Triangle Institute
RTLS   return to launch site
RTMS   Real Time Monitoring System
RTS   Relative Time Sequence
RTS   Remote Tracking Station
RVD   Rendezvous and Docking
RZS   Range Zero Set
S/C   spacecraft
S/N   Signal to Noise ratio
S/P   subpoint
S/R   Support Requirements
SA   Sensitivity Analysis
SA   Single Access
SAAIF   Sequential Access Auxiliary Interface File
SAEF   Spacecraft Assembly and Encapsulation Facility
SAIL   Shuttle Avionics Integration Laboratory
SAR   Schedule Add Requests
SAS   Support Analysis Section
SAU   Support Analysis Unit
SAU   Station Antenna Utilization
SAV   Scan And Verify
SAX   Astronomical X-ray Satellite
SBIR   Small Business Innovative Research
SC   spacecraft
SCFM   standard cubic feet per minute
SCN   Satellite Control Network
SCOPE   Scientific Committee on Problems of the Environment
SDC   Science Data Centre
SDD   System Design Document
SDR   System Design Review
SE   support equipment
SeaWiFS   Sea-Viewing Wide-Field-of-View Sensor
SFA   Space Flight Awareness
SFMT   Shuttle Facility Modification Team
SGLT   Space to Ground Link Terminal
SGSTS   Space to Ground Subsystem Test Set
SIC   Spacecraft Identification Code
SKY   Sky Network (DOD)
SLA   Service Level Agreement
SLC   Space Launch Complex
SLF   Shuttle Landing Facility
SLSS   Shuttle Launch Support System
SLWT   Super Light -Weight Tank
SM   Russian Service Module of ISS
SMG   Screens Using Machine Graphics
SML   Simulation Model Library
SMM   STDN Mission Manager
SMP   Software Management Plan
SN   Space Network
SNAR   Space Network Anomaly Report
SNL   Space Network Loading
SNOE   Student Nitric Oxide Experiment
SNUG   SN Users Guide
SOC   Simulation Operations Center
SOHO   Solar Heliosphere Observatory
SONET   Synchronous Optical Network
SOV   Start Of Visibility
SOW   Statement Of Work
SOX   Sulfur oxides
SPAN   Space Physics Analysis Network
SPAR   Software Programmable Advanced Receiver
SPARTAN   Shuttle Pointed Autonomous Research Tool for Astronomy
SPAS   Shuttle Pallet Satellite
SPEI   Simulation Parameters Electronic Interface
SPO   Station Priority Order
SPOT   Systeme Probatoire d-Observation de la Terre
SPP   Science Power Platform
SPR   System Problem Report
SPSR   Service Planning Segment Replacement
SPTR   South Pole TDRS Relay
SPV   Sensor Performance Verification
SR   Schedule Request
SRB   Solid Rocket Booster
SRM   Solid Rocket Motor
SSA   S-band Single Access
SSA-F   S-band Single Access - Forward
SSA-R   S-band Single Access - Return
SRB   Solid Rocket Booster
SSC   John C. Stennis Space Center
SSE   Specific Schedule Event
SSE   Space Science Enterprise
SSET   SRM Stacking Enhancement Tool
SSFP   Space Station Processing Facility
SSGLCS   Supersonic Gas-Liquid Cleaning System
SSME   Space Shuttle Main Engine
SSP   Software Standard and Procedure (manual)
SSP   Space Shuttle Program
SSR   System Support Request
SSTI   Small Spacecraft Technology Initiative Program
STDN   Spaceflight Tracking and Data Network
STK   Satellite Tool Kit
STOCC   Space Telescope Operations Control Center
STRR   System Test Readiness Review
STRV   Space Technology Research Vehicle
STS   Space Transportation System
SUD   SFP Utilization Document
SUG   System User's Guide
SUM   Summary
SUPIDEN   NCC Support Identification Code
SVS   Space Vision System
SYNC   Synchronous mission name with continuous visibilities
T   Time
TA   task agreement
TAL   Transatlantic Abort Landing
TAM   Technical Area Manager
TAO   Technical Area Owner
TCMS   Test, Checkout, and Monitor System
TCS   Telemetry Command Station
TD   Technical Directive
TDAC   Tracking, Data, Acquisition, and Communication
TDM   Tracking Data Message
TDRS   Tracking and Data Relay Satellite
TDRSS   Tracking and Data Relay Satellite System
TED   Total Energy Detector
TENSIR   Tendon Supported Inspection Robot
TER   Training Event Report
TFL   Timing and Frequency Laboratory
TGBS   Third Generation Beam Former System
TIC   TDRSS Interface Channel
TIM   Technical Interchange Meeting
TIMED   Thermosphere, Ionosphere, Mesosphere Energy and Dynamics
TIP   Technical Information Program
TLM   Telemetry
TM   Technical Memorandum
TOMS-EP   Total Ozone Mapping Spectrometer-Earth Probe
TOTS   Transportable Orbital Tracking Station
TQ   Total Quality
TR   Technical Response
TRACE   Transition Region and Coronal Explorer
TRMM   Tropical Rainfall Measuring Mission
TRR   Technical Response Request
TSE   TDRS H,I,J Spacecraft Simulator
TSM   Tail Service Mast
TSSR   TDAC Services Status Review
TT&C   Telemetry Tracking and Command
TUBE   TDRSS User Base Expansion
TURFTS   TDRSS User RF Test Set
TUT   TDRSS Unscheduled Time
UCF   University of Central Florida
UDF   Unit Development Folder
UG   Users Guide
UHF   Ultra-High Frequency
UPS   User Planning System
UPS   Uninterruptible Power System
UR   User Response
USA   United Space Alliance
USCA   Universal Signal Conditioning Amplifier
USCG   United States Coast Guard
USICU   United States International Standard Payload Rack Checkout Unit
USOS   U.S. Operations Center
UTC   Universal Time Coordinated (Once was called Greenwich Mean Time)
UTP   Unshielded Twisted Pair
UV   ultraviolet
UVa   the University of Virginia
V   volt
VAB   Vehicle Assembly Building
VAFB   Vandenberg Air Force Base
VDS   Voice Distribution System
VEST   Vehicle Electrical System Test
VETA   Verification Test Article
VFD   variable frequency drive
VHDL   Verilog Hardware Description Language
VHF   Very High Frequency
VHOK   Vertical Hatch Operations Kit
VLA   Very Large Array
VMC   Variability Model Coverage
VPF   Vertical Processing Facility
VUE   Visual User Environment
WAL   Wallops Tracking Station (NOAA)
WAN   Wide Area Network
WBS   Work Breakdown Structure
WD   Work Directive
WFC   Wide Field Camera (any of WFC1 and WFC2)
WFF   Wallops Flight Facility
WIND   Global Geospace Science Wind Spacecraft
WISE   Women in Science and Engineering
WOMI   Wireless Operation and Maintenance Instructions
WR   Western Range
WSC   White Sands Complex
WSG   Wide Area Network Security Gateway
WSGT   White Sands Ground Terminal
WSK   Water Servicing Kit
WSMR   White Sands Missile Range
WSSH   White Sands Space Harbor
WSTF   White Sands Test Facility
WWW   World Wide Web
XUV   Extreme Ultraviolet
XTE   X-ray Timing Explorer
ZOE   Zone Of Exclusion
According to this Cesium standard, the atomic day of 24 hours becomes the sum of 86,400 atomic seconds. The year is no longer 365.242,199 days but 290,091,200,500,000,000 atom oscillations, give or take one or two oscillations. The atomic second has become the new time standard measurement.

Timetable of Space Events: 1960s

Piloted missions

Achievement Country Crew Spacecraft Launch Date
First man in space Soviet Union Gagarin Vostok 1 April 12, 1961
First American in space United States Shepard Freedom 7 May 5, 1961
First day-long spaceflight Soviet Union Titov Vostok 2 August 6, 1961
First woman in space Soviet Union Tereshkova Vostok 6 June 16, 1963
First multi-person spaceflight Soviet Union Komarov, Yegorov, Feoktistov Voskhod 1 October 12, 1964
First space walk Soviet Union Belyayev, Leonov Voskhod 2 March 18, 1965
First 8-day space mission United States Cooper, Conrad Gemini 5 August 21, 1965
First space rendezvous United States Schirra, Stafford Gemini 6 December 15, 1965
First two-week space mission United States Borman, Lovell Gemini 7 December 4, 1965
First space docking United States Armstrong, Scott Gemini 8 March 16, 1966
First lunar orbit flight United States Borman, Lovell, Anders Apollo 8 December 21, 1968

First lunar landing

United States

Armstrong, Collins, Aldrin

Apollo 11

July 16, 1969

Robotic missions

Achievement Country Spacecraft Launch Date
First closeup photos of moon United States Ranger 7 July 28, 1964
First interplanetary flyby United States Mariner 2 August 27, 1962
First closeup photos of Mars United States Mariner 4 November 28, 1964
First photos from moon's surface Soviet Union Luna 9 January 31, 1966
First lunar satellite Soviet Union Luna 10 March 31, 1966
First automatic space docking Soviet Union Cosmos 186-188 October 27 / October 30, 1967