{"A-Train":["[Afternoon Train satellite constellation](https:\/\/en.wikipedia.org\/wiki\/A-train_%28satellite_constellation%29)"],"A-train":["[Afternoon Train satellite constellation](https:\/\/en.wikipedia.org\/wiki\/A-train_%28satellite_constellation%29)"],"ABCD":["Autonomous Spaceport Drone Bouncy Castle, for soft landings"],"ABS":["[Acrylonitrile Butadiene Styrene](https:\/\/en.wikipedia.org\/wiki\/Acrylonitrile_butadiene_styrene), hard plastic","Asia Broadcast Satellite, commsat operator"],"ABS-2A":["2016-06-15|F9-026 Full Thrust, core B1024, dual GTO comsat; ASDS landing failure due to early burn"],"ABS-3A":["2015-03-02|F9-016 v1.1, dual GTO comsat"],"ACES":["[Advanced Cryogenic Evolved Stage](https:\/\/en.wikipedia.org\/wiki\/Advanced_Cryogenic_Evolved_Stage)","[Advanced Crew Escape Suit](https:\/\/en.wikipedia.org\/wiki\/Advanced_Crew_Escape_Suit)"],"ACS":["Attitude Control System"],"ACST":["Australian Central Standard Time (UTC+9.5), Northern Territory and South Australia"],"ADBC":["Autonomous Spaceport Drone Bouncy Castle, for soft landings"],"ADCS":["Attitude Determination and Control System"],"ADELINE":["[Advanced Expendable Launcher with Innovative Engine Economy](https:\/\/en.wikipedia.org\/wiki\/Adeline_\\(rocket_stage\\)), Airbus Safran's returnable-engine first stage"],"ADEPT":["Adaptive Deployable Entry and Placement Technology carbon-fiber heatshield"],"AEB":["Agencia Espaciale Brasileira"],"AFB":["[Air Force Base](https:\/\/en.wikipedia.org\/wiki\/Military_airbase)"],"AFSS":["Automated Flight Safety System"],"AFTS":["Automated Flight Safety System","Autonomous Flight Termination System, see FTS"],"AGL":["Above Ground Level"],"AGuS":["Automatic Guidance System"],"AHRS":["Attitude and Heading Reference System"],"AIS":["[Automatic Identification System](https:\/\/en.wikipedia.org\/wiki\/Automatic_Identification_System)"],"AIT":["Assembly, Integration and Testing"],"AJR":["Aerojet Rocketdyne"],"AOA":["Angle of Attack"],"AOE":["Area of Effect"],"AOS":["Acquisition of Signal"],"APOD":["NASA's Astronomy Picture Of the Day"],"AR":["Area Ratio (between rocket engine nozzle and bell)","Aerojet Rocketdyne","Augmented Reality real-time processing","Anti-Reflective optical coating"],"AR-1":["AR's [RP-1\/LOX engine](https:\/\/en.wikipedia.org\/wiki\/Aerojet_Rocketdyne#AR1) proposed to replace RD-180"],"ARM":["Asteroid Redirect Mission","Advanced RISC Machines, embedded processor architecture"],"ARMD":["Aeronautics Research Mission Directorate, NASA"],"ARPA":["(Defense) Advanced Research Projects Agency, DoD"],"ARUM":["Asteroid Redirect Mission","Advanced RISC Machines, embedded processor architecture"],"ASAP":["Aerospace Safety Advisory Panel, NASA","Arianespace System for Auxiliary Payloads"],"ASAT":["[Anti-Satellite weapon](https:\/\/en.wikipedia.org\/wiki\/Anti-satellite_weapon)"],"ASDBC":["Autonomous Spaceport Drone Bouncy Castle, for soft landings"],"ASDS":["Autonomous Spaceport Drone Ship (landing platform)"],"ASIC":["Application-Specific Integrated Circuit"],"ASL":["[Airbus Safran Launchers](https:\/\/en.wikipedia.org\/wiki\/Airbus_Safran_Launchers), builders of the Ariane 6"],"ASOG":["A Shortfall of Gravitas, landing ~~barge~~ ship under construction"],"ASS":["Acronyms Seriously Suck"],"AST":["Federal Aviation Administration [Administrator for Space Transportation](http:\/\/www.faa.gov\/about\/office_org\/headquarters_offices\/ast\/)"],"ASoG":["A Shortfall of Gravitas, landing ~~barge~~ ship under construction"],"ATA":["Anthropomorphic Test Article (*Ripley*), flown on DM-1"],"ATK":["Alliant Techsystems, predecessor to Orbital ATK"],"ATP":["Acceptance Test Procedure"],"ATV":["Advanced Technology Vehicle, a launcher for sub-orbital experiments","[Automated Transfer Vehicle](https:\/\/en.wikipedia.org\/wiki\/Automated_Transfer_Vehicle), ESA cargo craft"],"AVI":["Avionics Operator"],"Amos-6":["2016-09-01|F9-029 Full Thrust, core B1028, ~~GTO comsat~~ Pre-launch test failure"],"AoA":["Angle of Attack"],"AoE":["Area of Effect"],"AsiaSat-6":["2014-09-07|F9-013 v1.1, GTO comsat"],"AsiaSat-8":["2014-08-05|F9-011 v1.1, GTO comsat"],"Asiasat-6":["2014-09-07|F9-013 v1.1, GTO comsat"],"Asiasat-8":["2014-08-05|F9-011 v1.1, GTO comsat"],"BARGE":["[Big-Ass Remote Grin Enhancer](https:\/\/twitter.com\/IridiumBoss\/status\/864579184483590144) coined by @IridiumBoss, see ASDS"],"BCC":["(Iron\/steel) [Body-Centered Cubic](https:\/\/en.wikipedia.org\/wiki\/Allotropes_of_iron) crystalline structure","Backup Control Center, MSFC (for ISS operations if Houston is inoperative)"],"BE-3":["Blue Engine 3 hydrolox rocket engine, developed by Blue Origin (2015), 490kN"],"BE-4":["Blue Engine 4 methalox rocket engine, developed by Blue Origin (2018), 2400kN"],"BE-4U":["Blue Engine 4 methalox rocket engine, Blue Origin (2018), vacuum-optimized"],"BEAM":["[Bigelow Expandable Activity Module](https:\/\/en.wikipedia.org\/wiki\/Bigelow_Expandable_Activity_Module)"],"BECO":["Booster Engine Cut-Off"],"BEO":["Beyond Earth Orbit"],"BFB":["Big Falcon Booster (see BFR)"],"BFG":["Big Falcon Grasshopper (\"Locust\"), BFS test article"],"BFR":["Big Falcon Rocket (2018 rebiggened edition)","Yes, the F stands for something else; no, you're not the first to notice"],"BFRPC":["BFR\/ITS\/MCT Planetary Colonizer, 2017 design"],"BFS":["Big Falcon Spaceship (see BFR)"],"BFT":["Big Falcon Tanker (see BFS)"],"BLEO":["Beyond Low Earth Orbit, in reference to human spaceflight"],"BO":["Blue Origin (*Bezos Rocketry*)"],"BPC":["BFR\/ITS\/MCT Planetary Colonizer, 2017 design"],"BSS":["Back-Shell Separation, event during Curiosity EDL"],"C3":["[Characteristic Energy](https:\/\/en.wikipedia.org\/wiki\/Characteristic_energy) above that required for escape"],"C3PO":["Commercial Crew and Cargo Program Office, NASA"],"CAA":["Crew Access Arm, for transfer of crew on a launchpad"],"CAP":["[Combat Air Patrol](https:\/\/en.wikipedia.org\/wiki\/Combat_air_patrol)"],"CARE":["Crew module Atmospheric Re-entry Experiment"],"CASSIOPE":["2013-09-29|F9-006 v1.1, [Cascade, Smallsat and Ionospheric Polar Explorer](https:\/\/en.wikipedia.org\/wiki\/CASSIOPE); engine starvation during landing attempt"],"CATO":["Catastrophe At Take Off, see RUD"],"CBC":["Common Booster Core","Canadian Broadcasting Corporation"],"CBM":["[Common Berthing Mechanism](https:\/\/en.wikipedia.org\/wiki\/Common_Berthing_Mechanism)"],"CC":["Commercial Crew program","Capsule Communicator (ground support)"],"CCAFS":["Cape Canaveral Air Force Station"],"CCAM":["Collision and Contaminance Avoidance Maneuver"],"CCDEV":["[Commercial Crew DEVelopment](https:\/\/en.wikipedia.org\/wiki\/Commercial_Crew_Development)"],"CCiCap":["[Commercial Crew Integrated Capability](https:\/\/en.wikipedia.org\/wiki\/Commercial_Crew_Development#Commercial_Crew_integrated_Capability)"],"CCtCap":["[Commercial Crew Transportation Capability](https:\/\/en.wikipedia.org\/wiki\/Commercial_Crew_Development#Commercial_Crew_Transportation_Capability_.28CCtCap.29)"],"CDR":["Critical Design Review","(As 'Cdr') Commander"],"CELSS":["Closed Ecological Life Support System"],"CF":["Carbon Fiber (Carbon Fibre) composite material","CompactFlash memory storage for digital cameras"],"CFD":["Computational Fluid Dynamics"],"CFRP":["Carbon-Fibre-Reinforced Polymer"],"CG":["Center of Gravity (see CoM)"],"CLCDR":["Central Launch Command Director"],"CLCDr":["Central Launch Command Director"],"CLPS":["[Commercial Lunar Payload Services](https:\/\/en.wikipedia.org\/wiki\/Commercial_Lunar_Payload_Services)"],"CME":["Coronal Mass Ejection"],"CMG":["Control Moment Gyroscope, RCS for the Station"],"CMP":["Command Module Pilot (especially for Apollo)"],"CNC":["Computerized Numerical Control, for precise machining or measuring"],"CNES":["Centre National d'Etudes Spatiales, space agency of France"],"CNSA":["Chinese National Space Administration"],"COG":["Center of Gravity (see CoM)"],"COM":["Center of Mass"],"CONUS":["[Contiguous United States](https:\/\/en.wikipedia.org\/wiki\/Contiguous_United_States)"],"COPV":["[Composite Overwrapped Pressure Vessel](https:\/\/en.wikipedia.org\/wiki\/Composite_overwrapped_pressure_vessel)"],"COSPAR":["Committee for Space Research"],"COTS":["[Commercial Orbital Transportation Services contract](https:\/\/www.nasa.gov\/cots)","Commercial\/Off The Shelf"],"COTS-1":["2010-12-08|F9-002, COTS demonstration"],"COTS-2":["2012-05-22|F9-003, COTS berthing demonstration"],"COTS-2\\+":["2012-05-22|F9-003, COTS berthing demonstration"],"CREAM":["Cosmic Radiation Effects and Activation Monitor, Station experiment slated for CRS-12"],"CRS":["[Commercial Resupply Services contract with NASA](http:\/\/www.nasa.gov\/mission_pages\/station\/structure\/launch\/)"],"CRS-1":["2012-10-08|F9-004, first CRS mission; secondary payload sacrificed"],"CRS-10":["2017-02-19|F9-032 Full Thrust, core B1031, Dragon cargo; first daytime RTLS"],"CRS-2":["2013-03-01|F9-005, Dragon cargo; final flight of Falcon 9 v1.0"],"CRS-3":["2014-04-18|F9-009 v1.1, Dragon cargo; soft ocean landing, first core with legs"],"CRS-4":["2014-09-21|F9-012 v1.1, Dragon cargo; soft ocean landing"],"CRS-5":["2015-01-10|F9-014 v1.1, Dragon cargo; first ASDS landing attempt, maneuvering failure"],"CRS-6":["2015-04-14|F9-018 v1.1, Dragon cargo; second ASDS landing attempt, overcompensated angle of entry"],"CRS-7":["2015-06-28|F9-020 v1.1, ~~Dragon cargo~~ Launch failure due to second-stage outgassing"],"CRS-8":["2016-04-08|F9-023 Full Thrust, core B1021, Dragon cargo; first ASDS landing"],"CRS-9":["2016-07-18|F9-027 Full Thrust, core B1025, Dragon cargo; RTLS landing"],"CRS2":["Commercial Resupply Services, second round contract; expected to start 2019"],"CSA":["Canadian Space Agency"],"CST":["(Boeing) Crew Space Transportation capsules","Central Standard Time (UTC-6)"],"CTB":["Cargo Transfer Bag"],"CUCU":["COTS UHF Communications Unit (ISS-to-Dragon radio)"],"CapCom":["Commercial Crew program","Capsule Communicator (ground support)"],"Capcom":["Commercial Crew program","Capsule Communicator (ground support)"],"Cd":["[Coefficient of Drag](https:\/\/en.wikipedia.org\/wiki\/Drag_coefficient)"],"CoG":["Center of Gravity (see CoM)"],"CoM":["Center of Mass"],"CoP":["Center of Pressure (see CoG)"],"DARPA":["(Defense) Advanced Research Projects Agency, DoD"],"DCS":["Decompression Sickness","*Digital Combat Simulator*, the flight simulator"],"DCSS":["Delta Cryogenic Second Stage"],"DEMO":["2010-06-04|Maiden Falcon 9 (F9-001, B0003), Dragon Spacecraft Qualification Unit"],"DIVH":["Delta IV Heavy"],"DLR":["Deutsches Zentrum fuer Luft und Raumfahrt (German Aerospace Center), Cologne"],"DM-1":["2019-03-02|SpaceX CCtCap Demo Mission 1"],"DM-2":["Scheduled|SpaceX CCtCap Demo Mission 2"],"DMLS":["[Selective Laser Melting](https:\/\/en.wikipedia.org\/wiki\/Direct_metal_laser_sintering) additive manufacture, also Direct Metal Laser Sintering"],"DP":["[Dynamic Positioning](https:\/\/en.wikipedia.org\/wiki\/Dynamic_positioning) ship navigation systems"],"DPL":["Downrange Propulsive Landing (on an ocean barge\/ASDS)"],"DRL":["Downrange Landing"],"DRO":["[Distant Retrograde Orbit](http:\/\/ccar.colorado.edu\/asen5050\/projects\/projects_2013\/Johnson_Kirstyn\/finalorbit.html)"],"DRRPL":["Down-Range Retro-Propulsive Landing"],"DRRRPL":["Down-Range Re-entry and Retro-Propulsive Landing"],"DRRRRPL":["Down-Range Retrograde, Re-entry, and Retro-Propulsive Landing maneuver"],"DRRRRRRPL":["Down-Range Retrograde RCS Rotation, Re-entry, and Retro-Propulsive Landing maneuver"],"DSCOVR":["2015-02-11|F9-015 v1.1, [Deep Space Climate Observatory](https:\/\/en.wikipedia.org\/wiki\/Deep_Space_Climate_Observatory) to L1; soft ocean landing"],"DSG":["NASA [Deep Space Gateway](https:\/\/www.nasa.gov\/feature\/deep-space-gateway-to-open-opportunities-for-distant-destinations), proposed for lunar orbit"],"DSH":["Deep Space Habitat"],"DSN":["Deep Space Network"],"DSQU":["2010-06-04|Maiden Falcon 9 (F9-001, B0003), Dragon Spacecraft Qualification Unit"],"DST":["NASA Deep Space Transport operating from the proposed DSG"],"DTN":["Delay\/Disruption Tolerant Networking"],"DUR":["Delightful Unscheduled Recovery"],"DVIC":["Digital Voice Inter-Communications subsystem between consoles in launch\/mission control"],"Dance-?floor":["Thermal Protection System for a spacecraft (on the Falcon 9 first stage, the engine \"Dance floor\")"],"DoD":["US Department of Defense"],"E2E":["Earth-to-Earth (suborbital flight)"],"EAR":["Export Administration Regulations, covering technologies that are not solely military"],"ECLSS":["Environment Control and Life Support System"],"EDAC":["Error Detection And Correction in integrated circuits"],"EDL":["Entry\/Descent\/Landing"],"EDRS":["European Data Relay System"],"EELV":["[Evolved Expendable Launch Vehicle](https:\/\/en.wikipedia.org\/wiki\/Evolved_Expendable_Launch_Vehicle)"],"EELV2":["Second phase of the EELV program"],"EGSE":["Electrical Ground Support Equipment"],"EHT":["Event Horizon Telescope"],"ELC":["EELV Launch Capability contract (\"assured access to space\")"],"ELDRS":["Enhanced Low Dose Rate Sensitivity (lower-intensity radiation causing more damage)"],"ELE":["[Extinction-Level Event](http:\/\/www.imdb.com\/title\/tt0120647\/)"],"ELT":["Extremely Large Telescope, under construction in Chile"],"EM drive":["Prototype-stage reactionless propulsion drive, using an asymmetrical resonant chamber and microwaves"],"EM-1":["[Exploration Mission 1](https:\/\/en.wikipedia.org\/wiki\/Exploration_Mission_1), Orion capsule; planned for launch on SLS"],"EML-1":["Earth-Moon Lagrange point 1"],"EML1":["Earth-Moon Lagrange point 1"],"EMU":["Extravehicular Mobility Unit (spacesuit)"],"EMdrive":["Prototype-stage reactionless propulsion drive, using an asymmetrical resonant chamber and microwaves"],"EOI":["Earth Orbital Insertion maneuver"],"EOL":["End Of Life"],"EPS":["Electrical Power System"],"ERP":["Effective Radiated Power"],"ERV":["Earth Return Vehicle"],"ESA":["European Space Agency"],"ESM":["European Service Module, component of the Orion capsule"],"ESO":["[European Southern Observatory](https:\/\/en.wikipedia.org\/wiki\/European_Southern_Observatory), builders of the VLT and EELT"],"ESPA":["EELV Secondary Payload Adapter standard for attaching to a second stage"],"ETLA":["Extended Three Letter Acronym (4+ letters)"],"ETO":["Earth-To-Orbit transport of materials"],"ETOV":["Earth To Orbit Vehicle (common parlance: \"rocket\")"],"EUS":["Exploration Upper Stage"],"EVA":["Extra-Vehicular Activity"],"EVEEGA":["Earth\/Venus\/Earth\/Earth Gravity Assist"],"EVS":["Extra-Vehicular Suit (see EVA)"],"Echostar-23":["2017-03-16|F9-031 Full Thrust, core B1030, GTO comsat; stage expended"],"Eutelsat-115WB":["2015-03-02|F9-016 v1.1, dual GTO comsat"],"Eutelsat-117WB":["2016-06-15|F9-026 Full Thrust, core B1024, dual GTO comsat; ASDS landing failure due to early burn"],"F1":["Rocketdyne-developed rocket engine used for Saturn V","SpaceX Falcon 1 (obsolete medium-lift vehicle)"],"F1F1":["2006-03-24|Falcon 1 first launch attempt; failure"],"F1F2":["2007-03-21|Falcon 1 second flight attempt; failure"],"F1F3":["2008-08-03|Falcon 1 third flight attempt; failure"],"F1F4":["2008-09-28|Falcon 1 fourth flight attempt, first success"],"F1F5":["2009-07-14|Falcon 1 fifth launch attempt, RazakSat to LEO"],"F9 FT":["Falcon 9 Full Thrust *or* Upgraded Falcon 9 *or* v1.2"],"F9-001":["2010-06-04|Maiden Falcon 9 (F9-001, B0003), Dragon Spacecraft Qualification Unit"],"F9-002":["2010-12-08|F9-002, COTS demonstration"],"F9-003":["2012-05-22|F9-003, COTS berthing demonstration"],"F9-004":["2012-10-08|F9-004, first CRS mission; secondary payload sacrificed"],"F9-005":["2013-03-01|F9-005, Dragon cargo; final flight of Falcon 9 v1.0"],"F9-006":["2013-09-29|F9-006 v1.1, [Cascade, Smallsat and Ionospheric Polar Explorer](https:\/\/en.wikipedia.org\/wiki\/CASSIOPE); engine starvation during landing attempt"],"F9-007":["2013-12-03|F9-007 v1.1, first SpaceX launch to GTO"],"F9-008":["2014-01-06|F9-008 v1.1 to GTO, re-entry burn attempted"],"F9-009":["2014-04-18|F9-009 v1.1, Dragon cargo; soft ocean landing, first core with legs"],"F9-010":["2014-07-14|F9-010 v1.1, six OG2 satellites to LEO; soft ocean landing"],"F9-011":["2014-08-05|F9-011 v1.1, GTO comsat"],"F9-012":["2014-09-21|F9-012 v1.1, Dragon cargo; soft ocean landing"],"F9-013":["2014-09-07|F9-013 v1.1, GTO comsat"],"F9-014":["2015-01-10|F9-014 v1.1, Dragon cargo; first ASDS landing attempt, maneuvering failure"],"F9-015":["2015-02-11|F9-015 v1.1, [Deep Space Climate Observatory](https:\/\/en.wikipedia.org\/wiki\/Deep_Space_Climate_Observatory) to L1; soft ocean landing"],"F9-016":["2015-03-02|F9-016 v1.1, dual GTO comsat"],"F9-017":["2015-04-27|F9-017 v1.1, GTO comsat"],"F9-018":["2015-04-14|F9-018 v1.1, Dragon cargo; second ASDS landing attempt, overcompensated angle of entry"],"F9-019":["2016-01-17|F9-019 v1.1, [Jason-3](https:\/\/en.wikipedia.org\/wiki\/Jason-3); leg failure after ASDS landing"],"F9-020":["2015-06-28|F9-020 v1.1, ~~Dragon cargo~~ Launch failure due to second-stage outgassing"],"F9-021":["2015-12-22|F9-021 Full Thrust, core B1019, 11 OG2 satellites to LEO; first RTLS landing"],"F9-022":["2016-03-04|F9-022 Full Thrust, core B1020, GTO comsat; ASDS lithobraking"],"F9-023":["2016-04-08|F9-023 Full Thrust, core B1021, Dragon cargo; first ASDS landing"],"F9-024":["2016-05-06|F9-024 Full Thrust, core B1022, GTO comsat; first ASDS landing from GTO"],"F9-025":["2016-05-27|F9-025 Full Thrust, core B1023, GTO comsat; ASDS landing"],"F9-026":["2016-06-15|F9-026 Full Thrust, core B1024, dual GTO comsat; ASDS landing failure due to early burn"],"F9-027":["2016-07-18|F9-027 Full Thrust, core B1025, Dragon cargo; RTLS landing"],"F9-028":["2016-08-14|F9-028 Full Thrust, core B1026, GTO comsat; ASDS landing"],"F9-029":["2016-09-01|F9-029 Full Thrust, core B1028, ~~GTO comsat~~ Pre-launch test failure"],"F9-032":["2017-02-19|F9-032 Full Thrust, core B1031, Dragon cargo; first daytime RTLS"],"F9EFT":["Falcon 9 v1.2.1, Even Fuller Thrust (uprated, 2016)"],"F9FT":["Falcon 9 Full Thrust *or* Upgraded Falcon 9 *or* v1.2"],"F9R":["Falcon 9 Reusable, test vehicles for development of landing technology"],"FAA":["Federal Aviation Administration"],"FAA-AST":["Federal Aviation Administration [Administrator for Space Transportation](http:\/\/www.faa.gov\/about\/office_org\/headquarters_offices\/ast\/)"],"FAP":["Fairing Acoustic Protection"],"FCC":["Federal Communications Commission","(Iron\/steel) [Face-Centered Cubic](https:\/\/en.wikipedia.org\/wiki\/Allotropes_of_iron) crystalline structure"],"FFSC":["Full-Flow Staged Combustion"],"FFSCC":["Full Flow Staged Combustion Cycle"],"FFSS":["Firefly Space Systems"],"FISO":["[Future In-Space Operations teleconferences](http:\/\/spirit.as.utexas.edu\/%7Efiso\/archivelist.htm)"],"FLEA":["Four Letter Extended Acronym (see ETLA)"],"FLP":["First Launch Pad at Satish Dhawan Space Centre, operational since 1990s"],"FLW":["The Following (as found on NOTAMs)"],"FMEA":["[Failure-Mode-and-Effects Analysis](https:\/\/en.wikipedia.org\/wiki\/Failure_mode_and_effects_analysis)"],"FOD":["[Foreign Object Damage](https:\/\/en.wikipedia.org\/wiki\/Foreign_object_damage) \/ Debris"],"FOS":["Factor of Safety for design of high-stress components (see COPV)"],"FPIP":["Flight Planning Integration Panel, FPWG"],"FPWG":["Flight Planning Work Group for the Space Station"],"FRAM":["Flight Releasable Attachment Mechanism"],"FRL":["Fire-Retardant Latex (White rocket paint)"],"FRSC":["Fuel-Rich Staged Combustion"],"FSS":["Fixed Service Structure at LC-39"],"FSW":["Flight Software"],"FTBA":["\"Flip This ~~Bi-~~ Booster Around\" boostback burn, part of first-stage landing procedure"],"FTS":["Flight Termination System"],"FTV":["Flight Test Vehicle (see hopper)"],"FoS":["Factor of Safety for design of high-stress components (see COPV)"],"G-LOC":["G-force-induced Loss Of Consciousness"],"GAO":["(US) Government Accountability Office"],"GCR":["Galactic Cosmic Rays, incident from outside the star system"],"GEO":["Geostationary Earth Orbit (35786km)"],"GLOW":["Gross Lift-Off Weight"],"GNC":["Guidance\/Navigation\/Control"],"GOX":["Gaseous Oxygen (contrast LOX)"],"GPC":["General-Purpose Computer (the [IBM AP-101](https:\/\/en.wikipedia.org\/wiki\/IBM_AP-101) on Shuttle)"],"GRB":["Gamma-Ray Burst"],"GSE":["Ground Support Equipment"],"GSFC":["Goddard Space Flight Center, Maryland"],"GSLV":["Geosynchronous Satellite Launch Vehicle","(India's) Geostationary Launch Vehicle"],"GSO":["Geosynchronous Orbit (any Earth orbit with a 24-hour period)","Guang Sheng Optical telescopes"],"GTAW":["[Gas Tungsten Arc Welding](https:\/\/en.wikipedia.org\/wiki\/Gas_tungsten_arc_welding) (or Tungsten Inert Gas)"],"GTC":["Gran Telescopio Canarias, Spain"],"GTE":["Ground Test Equipment (as opposed to Ground Support Equipment, which would support a launch)"],"GTO":["[Geosynchronous Transfer Orbit](http:\/\/www.planetary.org\/blogs\/jason-davis\/20140116-how-to-get-a-satellite-to-gto.html)"],"GTO-1500":["Geosynchronous Transfer Orbit (185 x 35786km, 0 inclination), requires 1500m\/s to reach GEO"],"GTO-1800":["Geosynchronous Transfer Orbit (185 x 35786km, 27-degree inclination), requires 1800m\/s to reach GEO"],"GeV":["Giga-Electron-Volts, measure of energy for particles"],"H1":["First half of the year\/month"],"H2":["Molecular hydrogen","Second half of the year\/month"],"HAN":["[Hydroxylammonium Nitrate](https:\/\/en.wikipedia.org\/wiki\/Hydroxylammonium_nitrate)"],"HASC":["(US) House (of Representatives) Armed Services Committee"],"HCO":["Heliocentric Orbit"],"HDEV":["High Definition Earth Viewing experiment, fitted to ISS"],"HEEO":["Highly Elliptical Earth Orbit"],"HEMO":["Highly Elliptical Mars Orbit"],"HEO":["High Earth Orbit (above 35780km)","Highly Elliptical Orbit","Human Exploration and Operations (see HEOMD)"],"HEOMD":["Human Exploration and Operations Mission Directorate, NASA"],"HERA":["[Human Exploration Research Analog](https:\/\/www.nasa.gov\/analogs\/hera)"],"HEU":["Highly-Enriched Uranium, fissile material with a high percentage of U-235 (\"boom stuff\")"],"HIAD":["Hypersonic Inflatable Aerodynamic Decelerator (derived from LDSD)"],"HIF":["Horizontal Integration Facility"],"HIL":["Hardware in the Loop, see HITL"],"HITL":["Hardware in the Loop","Human in the Loop"],"HLC-39A":["**Historic** Launch Complex 39A, Kennedy (Saturn V, Shuttle, SpaceX F9\/Heavy)"],"HLC39A":["**Historic** Launch Complex 39A, Kennedy (Saturn V, Shuttle, SpaceX F9\/Heavy)"],"HLLV":["Heavy Lift Launch Vehicle (20-50 tons to LEO)"],"HLV":["Heavy Lift Launch Vehicle (20-50 tons to LEO)"],"HPFTP":["High Pressure Fuel Turbopump"],"HPOTP":["High Pressure Oxidiser Turbopump"],"HPTP":["High Pressure Turbopump"],"HRLV":["[ISRO] Human Rated Launch Vehicle"],"HSF":["Human Space Flight"],"HST":["Hubble Space Telescope"],"HTHL":["Horizontal Takeoff, Horizontal Landing (*Skylon* (proposed))"],"HTPB":["Hydroxyl-terminated polybutadiene, solid propellant"],"HTS":["Horizontal Test Stand"],"HUD":["Head(s)-Up Display, often implemented as a projection"],"HWIL":["Hardware in the Loop, see HITL"],"Hydrolox":["Portmanteau: liquid hydrogen\/liquid oxygen mixture"],"IAC":["International Astronautical Congress, annual meeting of IAF members","In-Air Capture of space-flown hardware"],"IAF":["[International Astronautical Federation](http:\/\/www.iafastro.org\/)","Indian Air Force","Israeli Air Force"],"IANARS":["I Am Not A Rocket Scientist, but..."],"ICBM":["Intercontinental Ballistic Missile"],"ICPS":["Interim Cryogenic Propulsion Stage"],"ICT":["Interplanetary Colonial Transport (see ITS)"],"IDA":["[International Docking Adapter](https:\/\/en.wikipedia.org\/wiki\/International_Docking_Adapter)"],"IDSN":["Indian Deep Space Network"],"IDSS":["[International Docking System Standard](https:\/\/en.wikipedia.org\/wiki\/International_Docking_System_Standard)"],"IFA":["In-Flight Abort test"],"IFAT":["In-Flight Abort test"],"IFR":["[Instrument Flight Rules](https:\/\/en.wikipedia.org\/wiki\/Instrument_flight_rules)"],"IIP":["Instantaneous Impact Point (where a payload would land if Stage 2 failed)"],"ILC":["Initial Launch Capability"],"ILS":["[International Launch Services](https:\/\/en.wikipedia.org\/wiki\/International_Launch_Services)","[Instrument Landing System](https:\/\/en.wikipedia.org\/wiki\/Instrument_landing_system)"],"IM":["Initial Mass deliverable to a given orbit, without accounting for fuel"],"IMGTO":["Initial Mass deliverable to GTO, see IM"],"IMLEO":["Initial Mass deliverable to LEO, see IM"],"IMRS":["International Mars Research Station (proposed by Blue Mars)"],"IMU":["Inertial Measurement Unit"],"INS":["[Inertial Navigation System](https:\/\/en.wikipedia.org\/wiki\/Inertial_navigation_system)"],"IRFNA":["Inhibited Red Fuming Nitric Acid, mixed with hydrogen fluoride for stability"],"IRNSS":["Indian Regional Navigation Satellite System"],"IRT":["Independent Review Team"],"ISAP":["In-Situ Air Production"],"ISC":["Institutional Services Contract, under which a private company provides support services to NASA\/USAF"],"ISECG":["International Space Exploration Coordinating Group"],"ISEP":["In-Situ Electricity\/Energy Production"],"ISFP":["In-Situ Food Production"],"ISL":["Inter-Satellite Link communication between satellites in orbit"],"ISP":["Specific impulse (as explained by [Scott Manley](https:\/\/www.youtube.com\/watch?v=nnisTeYLLgs) on YouTube)"],"ISPP":["In-Situ Propellant Production"],"ISPR":["International Standard Payload Rack"],"ISRO":["Indian Space Research Organisation"],"ISRU":["[In-Situ Resource Utilization](https:\/\/en.wikipedia.org\/wiki\/In_situ_resource_utilization)"],"ISSP":["[International Space Station Program](https:\/\/en.wikipedia.org\/wiki\/International_Space_Station_program), the legal framework for ISS maintenance"],"ISSRDC":["[International Space Station Research and Development Conference](https:\/\/www.issconference.org\/about\/)"],"ISTRAC":["ISRO Telemetry, Tracking and Command Network"],"ISW":["(US) Institute for the Study of War"],"ISWP":["In-Situ Water Production"],"ITAR":["(US) International Traffic in Arms Regulations"],"ITC":["Interplanetary Colonial Transport (see ITS)"],"ITN":["Interplanetary Transport Network"],"ITP":["Interplanetary Colonial Transport (see ITS)"],"ITS":["Interplanetary Transport System (2016 oversized edition) (see MCT)","[Integrated Truss Structure](https:\/\/en.wikipedia.org\/wiki\/Integrated_Truss_Structure)"],"ITSPC":["BFR\/ITS\/MCT Planetary Colonizer, 2017 design"],"ITU":["International Telecommunications Union, responsible for coordinating radio spectrum usage"],"IVA":["Intra-Vehicular Activity"],"IVS":["Intra-Vehicular Suit (see IVA)"],"Inmarsat-5 F4":["2017-05-16|F9-034 Full Thrust, core B1034, GTO comsat; expended"],"Iridium-1":["2017-01-14|F9-030 Full Thrust, core B1029, 10x Iridium-NEXT to LEO; first landing on JRTI"],"Isp":["Specific impulse (as explained by [Scott Manley](https:\/\/www.youtube.com\/watch?v=nnisTeYLLgs) on YouTube)"],"JATO":["[Jet-Assisted Take-Off](https:\/\/en.wikipedia.org\/wiki\/JATO), used by aircraft on short runways"],"JAXA":["Japan Aerospace eXploration Agency"],"JCSAT":["Japan Communications Satellite series, by JSAT Corp"],"JCSAT-14":["2016-05-06|F9-024 Full Thrust, core B1022, GTO comsat; first ASDS landing from GTO"],"JCSAT-16":["2016-08-14|F9-028 Full Thrust, core B1026, GTO comsat; ASDS landing"],"JOI":["Jovian Orbital Insertion maneuver"],"JPADS":["Air Force [Joint Precision Air Drop System](https:\/\/en.wikipedia.org\/wiki\/Joint_Precision_Airdrop_System), possible parafoils for fairing recovery"],"JPL":["Jet Propulsion Lab, California"],"JRTI":["Just Read The Instructions, Pacific landing ~~barge~~ ship"],"JRtI":["Just Read The Instructions, Pacific landing ~~barge~~ ship"],"JSC":["Johnson Space Center, Houston"],"JWST":["James Webb infra-red Space Telescope"],"Jason-3":["2016-01-17|F9-019 v1.1, [Jason-3](https:\/\/en.wikipedia.org\/wiki\/Jason-3); leg failure after ASDS landing"],"KARI":["Korean Aerospace Research Institute"],"KOS":["Keep Out Sphere, 200m radius from ISS","Kerbal Operating System, the KSP in-game rocket OS"],"KSC":["Kennedy Space Center, Florida"],"KSP":["*Kerbal Space Program*, the rocketry simulator"],"Kerolox":["Portmanteau: kerosene\/liquid oxygen mixture"],"L1":["[Lagrange Point](https:\/\/en.wikipedia.org\/wiki\/Lagrangian_point) 1 of a two-body system, between the bodies"],"L2":["[Lagrange Point](https:\/\/en.wikipedia.org\/wiki\/Lagrangian_point) 2 ([Sixty Symbols](https:\/\/www.youtube.com\/watch?v=mxpVbU5FH0s) video explanation)","Paywalled section of the NasaSpaceFlight forum"],"L3":["[Lagrange Point](https:\/\/en.wikipedia.org\/wiki\/Lagrangian_point) 3 of a two-body system, opposite L2"],"L4":["\"Trojan\" [Lagrange Point](https:\/\/en.wikipedia.org\/wiki\/Lagrangian_point) 4 of a two-body system, 60 degrees ahead of the smaller body"],"L5":["\"Trojan\" [Lagrange Point](https:\/\/en.wikipedia.org\/wiki\/Lagrangian_point) 5 of a two-body system, 60 degrees behind the smaller body"],"LAS":["Launch Abort System"],"LBT":["Large Binocular Telescope, Arizona"],"LC-13":["Launch Complex 13, Canaveral (SpaceX Landing Zone 1)"],"LC-39A":["Launch Complex 39A, Kennedy (SpaceX F9\/Heavy)"],"LC13":["Launch Complex 13, Canaveral (SpaceX Landing Zone 1)"],"LC39A":["Launch Complex 39A, Kennedy (SpaceX F9\/Heavy)"],"LC39a":["Launch Complex 39A, Kennedy (SpaceX F9\/Heavy)"],"LCC":["Launch Control Center"],"LCH4":["Liquid Methane"],"LDRO":["[Distant Retrograde Orbit](http:\/\/ccar.colorado.edu\/asen5050\/projects\/projects_2013\/Johnson_Kirstyn\/finalorbit.html)","Lunar Distant Retrograde Orbit"],"LDSD":["Low-Density Supersonic Decelerator test vehicle"],"LEM":["(Apollo) [Lunar Excursion Module](https:\/\/en.wikipedia.org\/wiki\/Apollo_Lunar_Module) (also Lunar Module)"],"LEO":["Low Earth Orbit (180-2000km)","Law Enforcement Officer (most often mentioned during transport operations)"],"LES":["Launch Escape System"],"LEU":["Low-Enriched Uranium, fissile material that's not explosively so"],"LH2":["Liquid Hydrogen"],"LIDAR":["[Light Detection and Ranging](https:\/\/en.wikipedia.org\/wiki\/Lidar)"],"LIGO":["Laser Interferometer Gravitational-wave Observatory"],"LISA":["Laser Interferometer Space Antenna"],"LLCC":["(SpaceX) Launch and Landing Control Center, Port Canaveral"],"LLO":["Low Lunar Orbit (below 100km)"],"LMO":["Low Mars Orbit"],"LMP":["(Apollo) Lunar Module Pilot"],"LN2":["Liquid Nitrogen"],"LNG":["Liquefied Natural Gas"],"LO2":["Liquid Oxygen (more commonly LOX)"],"LOC":["Loss of Crew"],"LOLI":["Limited-Operational-Life Item (lasts a number of cycles before needing replacement)"],"LOM":["Loss of Mission"],"LOP-G":["Lunar Orbital Platform - Gateway, formerly DSG"],"LOPG":["Lunar Orbital Platform - Gateway, formerly DSG"],"LOS":["Loss of Signal","Line of Sight"],"LOV":["Loss Of Vehicle"],"LOX":["Liquid Oxygen"],"LPFTP":["Low Pressure Fuel Turbopump"],"LPG":["Liquified Petroleum Gas","[Liquified Pigeon Guts](https:\/\/www.reddit.com\/r\/SpaceXLounge\/comments\/6to7zk\/how_many_pigeons_can_a_falcon_9_launch_into_leo\/dlmmcg3\/)"],"LPOTP":["Low Pressure Oxidiser Turbopump"],"LPSC":["Liquid Propulsion Systems Centre"],"LPTP":["Low Pressure Turbopump"],"LRR":["Launch Readiness Review"],"LSA":["Launch Services Agreement"],"LSP":["Launch Service Provider"],"LUT":["Launch Umbilical Tower","Look-Up Table"],"LV":["Launch Vehicle (common parlance: \"rocket\"), see ETOV"],"LZ":["Landing Zone"],"LZ-1":["Landing Zone 1, Cape Canaveral (see LC-13)"],"LZ-2":["Landing Zone 2, Vandenberg (see SLC-4W)"],"LZ1":["Landing Zone 1, Cape Canaveral (see LC-13)"],"Locust":["Big Falcon Grasshopper (\"Locust\"), BFS test article"],"MAF":["Michoud Assembly Facility, Louisiana"],"MAV":["*Mars Ascent Vehicle* ([possibly fictional](https:\/\/en.wikipedia.org\/wiki\/The_Martian_\\(Weir_novel\\)))"],"MBA":["~~Moonba-~~ Mars Base Alpha"],"MCC":["Mission Control Center","Mars Colour Camera"],"MCC-H":["Nasa's Mission Control Center (Houston), Texas"],"MCC-M":["Roscosmos' Mission Control Center (Moscow), Russia"],"MCC-X":["Mission Control Center (SpaceX), Hawthorne, California"],"MCP":["Mechanical Counterpressure spacesuit"],"MCT":["Mars Colonial Transporter (see ITS)"],"MCTPC":["BFR\/ITS\/MCT Planetary Colonizer, 2017 design"],"MDA":["[Missile Defense Agency](https:\/\/en.wikipedia.org\/wiki\/Missile_Defense_Agency)","[MacDonald, Dettwiler and Associates](https:\/\/en.wikipedia.org\/wiki\/MacDonald,_Dettwiler_and_Associates), owner of SSL, builder of Canadarm"],"MECO":["Main Engine Cut-Off","[MainEngineCutOff](https:\/\/mainenginecutoff.com\/) podcast"],"MENA":["Middle East and North Africa, Morocco to Iran"],"MEO":["Medium Earth Orbit (2000-35780km)"],"MEOP":["Maximum Expected Operating Pressure"],"MER":["Mars Exploration Rover (Spirit\/Opportunity)","Mission Evaluation Room in back of Mission Control"],"MES":["Main Engine Start"],"MET":["[Mission Elapsed Time](https:\/\/en.wikipedia.org\/wiki\/Mission_Elapsed_Time)"],"MFR":["Medium ~~Fu-~~ Falcon Rocket (Falcon 9\/Heavy), contrast BFR","Manipulator Foot Restraint, support equipment for Hubble servicing"],"MGS":["Mars Global Surveyor satellite"],"MHI":["Mitsubishi Heavy Industries, builder of the H-IIA"],"MLLV":["Medium Lift Launch Vehicle (2-20 tons to LEO)"],"MLP":["Mobile Launcher Platform"],"MLV":["Medium Lift Launch Vehicle (2-20 tons to LEO)"],"MMH":["Mono-Methyl Hydrazine, (CH3)HN-NH2; part of NTO\/MMH hypergolic mix"],"MMOD":["Micro-Meteoroids and Orbital Debris"],"MMSEV":["[Multi-Mission Space Exploration Vehicle](https:\/\/www.nasa.gov\/exploration\/technology\/space_exploration_vehicle\/index.html)"],"MMT":["Multiple-Mirror Telescope, Arizona","Multiscale Median Transform, an alternative to wavelet image compression"],"MMU":["[Manned Maneuvering Unit](https:\/\/en.wikipedia.org\/wiki\/Manned_Maneuvering_Unit), untethered spacesuit propulsion equipment"],"MOI":["Mars Orbital Insertion maneuver"],"MOM":["Mars Orbiter Mission"],"MON":["Mixed Oxides of Nitrogen"],"MPLM":["[Multi-Purpose Logistics Module](https:\/\/en.wikipedia.org\/wiki\/Multi-Purpose_Logistics_Module) formerly used to supply ISS"],"MRO":["Mars Reconnaisance Orbiter","Maintenance, Repair and\/or Overhaul"],"MSFC":["Marshall Space Flight Center, Alabama"],"MSL":["Mars Science Laboratory (Curiosity)","Mean Sea Level, reference for altitude measurements"],"MT":["~~Milli-~~ *Metric* Tonnes"],"MZ":["(Yusaku) Maezawa, first confirmed passenger for BFR"],"MaxQ":["Maximum aerodynamic pressure"],"MeV":["Mega-Electron-Volts, measure of energy for particles"],"MegaROSA":["Multi-element Roll-Out Solar Array"],"Methalox":["Portmanteau: methane\/liquid oxygen mixture"],"MonacoSat":["2015-04-27|F9-017 v1.1, GTO comsat"],"N-1":["Raketa Nositel-1, Soviet super-heavy-lift (\"Russian Saturn V\")"],"N1":["Raketa Nositel-1, Soviet super-heavy-lift (\"Russian Saturn V\")"],"NA":["New Armstrong, super-heavy lifter proposed by Blue Origin"],"NAC":["NASA Advisory Council"],"NAP":["No-Acronym Policy"],"NAS":["National Airspace System","[Naval Air Station](https:\/\/en.wikipedia.org\/wiki\/Naval_air_station)"],"NAVIC":["Navigation with Indian Constellation"],"NDA":["Non-Disclosure Agreement"],"NDS":["[NASA Docking System](https:\/\/en.wikipedia.org\/wiki\/NASA_Docking_System), implementation of the international standard"],"NEO":["Near-Earth Object"],"NEP":["Nuclear Electric Vehicle propulsion"],"NERVA":["Nuclear Engine for Rocket Vehicle Application (proposed engine design)"],"NET":["No Earlier Than"],"NEV":["Nuclear Electric Vehicle propulsion"],"NG":["New Glenn, two\/three-stage orbital vehicle by Blue Origin","Natural Gas (as opposed to pure methane)","Northrop Grumman, aerospace manufacturer"],"NGIS":["Northrop Grumman Innovation Systems, formerly OATK"],"NGLLC":["Northrop-Grumman [Lunar Lander Challenge](https:\/\/en.wikipedia.org\/wiki\/Lunar_Lander_Challenge), 2006-09"],"NGSO":["Non-Geostationary Orbit"],"NIAC":["NASA Innovative Advanced Concepts program"],"NICER":["[Neutron star Interior Composition ExploreR](http:\/\/www.nasa.gov\/mission_pages\/station\/research\/experiments\/1966.html), an ISS experiment"],"NLS":["NASA Launch Services contracts"],"NNPT":["Nuclear (Non-)Proliferation Treaty"],"NOAA":["National Oceanic and Atmospheric Administration, responsible for US ~~generation~~ monitoring of the climate"],"NORAD":["North American Aerospace Defense command"],"NOTAM":["[Notice to Airmen](https:\/\/en.wikipedia.org\/wiki\/NOTAM) of flight hazards"],"NPT":["Nuclear (Non-)Proliferation Treaty"],"NRE":["Non-Recurring Expense"],"NRHO":["Near-Rectilinear Halo Orbit"],"NRO":["(US) National Reconnaissance Office","Near-Rectilinear Orbit, see NRHO"],"NROL":["(US) National Reconnaissance Office","Near-Rectilinear Orbit, see NRHO","Launch for the (US) National Reconnaissance Office"],"NROL-76":["2017-05-01|F9-033 Full Thrust, core B1032, ^(classified payload); landed at LZ-1"],"NS":["New Shepard suborbital launch vehicle, by Blue Origin","Nova Scotia, Canada","Neutron Star"],"NSF":["[NasaSpaceFlight forum](http:\/\/forum.nasaspaceflight.com)","National Science Foundation"],"NSSL":["National Security Space Launch, formerly EELV"],"NTO":["diNitrogen TetrOxide, N2O4; part of NTO\/MMH hypergolic mix"],"NTP":["Nuclear Thermal Propulsion","Network Time Protocol"],"NTR":["Nuclear Thermal Rocket"],"NdGT":["Neil deGrasse Tyson"],"OA-4":["2015-12-06|ULA Atlas V, OATK Cygnus cargo"],"OA-5":["2016-10-17|OATK Antares 230, Cygnus cargo"],"OA-6":["2016-03-23|ULA Atlas V, OATK Cygnus cargo"],"OATK":["Orbital Sciences \/ Alliant Techsystems merger, launch provider"],"OCISLY":["Of Course I Still Love You, Atlantic landing ~~barge~~ ship"],"OECD":["Organisation for Economic Cooperation and Development"],"OFT":["Orbital Flight Test"],"OG2":["Orbcomm's Generation 2 17-satellite network (see OG2-2 for first successful F9 landing)"],"OG2-1":["2014-07-14|F9-010 v1.1, six OG2 satellites to LEO; soft ocean landing"],"OG2-2":["2015-12-22|F9-021 Full Thrust, core B1019, 11 OG2 satellites to LEO; first RTLS landing"],"OLIT":["Orbital Launch Integration Tower"],"OLM":["Orbital Launch Mount"],"OML":["Outer Mold Line, outer profile of an aircraft\/aeroshell"],"OMS":["Orbital Maneuvering System"],"OOA":["Orbit Once Around launch maneuver"],"OPTEMPO":["Operating\/Operational Tempo"],"ORSC":["Oxidizer-Rich Staged Combustion"],"OSM":["Operations Safety Manager"],"OTF":["Orbital Tank Farm"],"OTV":["Orbital Test Vehicle"],"OWL":["[Overwhelmingly Large Telescope](https:\/\/en.wikipedia.org\/wiki\/Overwhelmingly_Large_Telescope) project, abandoned in favor of ELT"],"Orb-1":["2014-01-09|Orbital Antares 120, first Cygnus cargo"],"Orb-2":["2014-07-13|Orbital Antares 120, Cygnus cargo"],"Orb-3":["2014-10-28|Orbital Antares 130, ~~Cygnus cargo~~ Thrust loss at launch"],"Orb-D1":["2013-09-18|Orbital Antares 110, Cygnus cargo; COTS demo"],"PAF":["Payload Attach Fitting"],"PAO":["Public Affairs Officer"],"PAS":["Payload Adapter System"],"PAZ":["Formerly [SEOSAR-PAZ](https:\/\/directory.eoportal.org\/web\/eoportal\/satellite-missions\/p\/paz), an X-band SAR from Spain"],"PCV":["Port Canaveral"],"PDR":["Preliminary Design Review"],"PDV":["Powered Descent Vehicle for retro-propulsive landing"],"PICA-X":["Phenolic Impregnated-Carbon Ablative heatshield compound, as modified by SpaceX"],"PLF":["Payload Fairing"],"PLSS":["Personal Life Support System"],"PMA":["ISS Pressurized Mating Adapter"],"PMD":["Propellant Management Device"],"PMF":["Propellant Mass Fraction"],"PNT":["Positioning, Navigation and Timing"],"PPE":["Power and Propulsion Element"],"PPF":["SpaceX Payload Processing Facility, Cape Canaveral"],"PSLV":["Polar Satellite Launch Vehicle","[Polar Satellite Launch Vehicle](https:\/\/en.wikipedia.org\/wiki\/Polar_Satellite_Launch_Vehicle)"],"PSLV-CA":["Polar Satellite Launch Vehicle - Core Alone (without strap-on boosters)"],"PSLV-G":["Polar Satellite Launch Vehicle, with six 1 m diameter, 10 m long strap-on boosters"],"PSLV-XL":["Polar Satellite Launch Vehicle, with six 1 m diameter, 13.5 m long strap-on boosters"],"PSOM":["Solid Propellant Strap-On Motor, used in the PSLV"],"PSP":["Parker Solar Probe"],"PTC":["Passive Thermal Control"],"PTK":["Roscosmos [Piloted Transport Ship, New Generation](https:\/\/en.wikipedia.org\/wiki\/Prospective_Piloted_Transport_System)"],"PTK-NP":["Roscosmos [Piloted Transport Ship, New Generation](https:\/\/en.wikipedia.org\/wiki\/Prospective_Piloted_Transport_System)"],"QA":["Quality Assurance\/Assessment"],"QAM":["Quality Assurance Manager","[Quadrature Amplitude Modulation](https:\/\/en.wikipedia.org\/wiki\/QAM)"],"QD":["Quick-Disconnect"],"RAAN":["[Right Ascension of the Ascending Node](https:\/\/en.wikipedia.org\/wiki\/Longitude_of_the_ascending_node)"],"RAL":["Rutherford Appleton Laboratory, UK"],"RCC":["Reinforced Carbon-Carbon"],"RCO":["Range Control Officer"],"RCS":["Reaction Control System"],"RD-180":["[RD-series Russian-built rocket engine](https:\/\/en.wikipedia.org\/wiki\/RD-180), used in the Atlas V first stage"],"REL":["Reaction Engines Limited, England"],"RFIC":["Radio Frequency Integrated Circuit"],"RFNA":["Red Fuming Nitric Acid, hypergolic oxidiser"],"RFP":["Request for Proposal"],"RIO":["[Radar Intercept Officer](https:\/\/en.wikipedia.org\/wiki\/Naval_flight_officer)"],"RLV":["Reusable Launch Vehicle"],"RLV-TD":["Reusable Launch Vehicle - Technology Demonstrator"],"RNTLS":["Return Near To Launch Site (ASDS in port)"],"ROC":["Range Operations Coordinator","Radius of Curvature"],"ROOMBA":["[Remotely-Operated Orientation and Mass Balance Adjuster](https:\/\/www.reddit.com\/r\/spacex\/comments\/6k8gzg\/\/djk5g68\/), used to hold down a stage on the ASDS"],"ROSA":["Roll-Out Solar Array (designed by Deployable Space Systems)"],"ROSCOSMOS":["[State Corporation for Space Activities, Russia](https:\/\/en.wikipedia.org\/wiki\/Roscosmos_State_Corporation)"],"RP-1":["Rocket Propellant 1 (enhanced kerosene)"],"RPA":["[\"Rocket Propulsion Analysis\"](http:\/\/www.propulsion-analysis.com\/index.htm) computational tool"],"RPY":["Roll\/Pitch\/Yaw"],"RRR":["Reflight Readiness Review (see LRR)"],"RS-25":["Rocketdyne-developed rocket engine used for Shuttle; see SSME, SLS","[Space Shuttle Main Engine](https:\/\/en.wikipedia.org\/wiki\/Space_Shuttle_main_engine)"],"RSI":["Reusable Surface Insulation (Shuttle's ceramic fiber tiles)"],"RSS":["[Rotating Service Structure](https:\/\/en.wikipedia.org\/wiki\/Kennedy_Space_Center_Launch_Complex_39#Launch_towers) at LC-39","Realscale Solar System, mod for KSP"],"RTF":["Return to Flight"],"RTG":["Radioisotope Thermoelectric Generator"],"RTLS":["Return to Launch Site"],"RTNLS":["Return Near To Launch Site (ASDS in port)"],"RUAG":["R\u00fcstungs Unternehmen Aktiengesellschaft (Joint Stock Defense Company), Switzerland"],"RUD":["Rapid Unplanned Disassembly","Rapid Unscheduled Disassembly","Rapid Unintended Disassembly"],"RUS":["Raptor-powered Upper Stage, and\/or ground equipment to support same"],"Raptor":["[Methane-fueled rocket engine](https:\/\/en.wikipedia.org\/wiki\/Raptor_\\(rocket_engine_family\\)) under development by SpaceX"],"Roomba":["[Remotely-Operated Orientation and Mass Balance Adjuster](https:\/\/www.reddit.com\/r\/spacex\/comments\/6k8gzg\/\/djk5g68\/), used to hold down a stage on the ASDS"],"Roscosmos":["[State Corporation for Space Activities, Russia](https:\/\/en.wikipedia.org\/wiki\/Roscosmos_State_Corporation)"],"S\/C":["Spacecraft"],"SAA":["[Space Act Agreement](https:\/\/en.wikipedia.org\/wiki\/Space_Act_Agreement), formal authorization of 'other transactions'"],"SABRE":["Synergistic Air-Breathing Rocket Engine, hybrid design by REL"],"SAFER":["[Simplified Aid For EVA Rescue](https:\/\/en.wikipedia.org\/wiki\/Simplified_Aid_For_EVA_Rescue)"],"SAR":["Synthetic Aperture Radar (increasing resolution with parallax)"],"SAS":["[Stability Augmentation System](http:\/\/wiki.kerbalspaceprogram.com\/wiki\/SAS), available when launching craft in KSP"],"SBSA":["Space Situational Based Awareness"],"SBSP":["Space-Based Solar Power generation"],"SCADA":["[Supervisory Control And Data Acquisition](https:\/\/en.wikipedia.org\/wiki\/SCADA) remote monitoring and control"],"SCH4":["Slush\/Supercooled Liquid Methane"],"SDS":["[Satellite Data System](https:\/\/en.wikipedia.org\/wiki\/Satellite_Data_System)"],"SDSC":["Satish Dhawan Space Centre"],"SEB":["Single-Event induced Burnout, radiation damage causing destructively high current"],"SECO":["Second-stage Engine Cut-Off"],"SEE":["Single-Event Effect of radiation impact"],"SEGR":["Single-Event Gate Rupture, transistor gate destroyed by radiation impact"],"SEL":["Single-Event Latchup, transistor stuck high due to radiation damage","Sun-Earth Lagrange point"],"SEP":["Solar Electric Propulsion","[Solar Energetic Particle](https:\/\/en.wikipedia.org\/wiki\/Solar_energetic_particle)","Soci\u00e9t\u00e9 Europ\u00e9enne de Propulsion"],"SES":["Formerly Société Européenne des Satellites, a major SpaceX customer","Second-stage Engine Start"],"SES-8":["2013-12-03|F9-007 v1.1, first SpaceX launch to GTO"],"SES-9":["2016-03-04|F9-022 Full Thrust, core B1020, GTO comsat; ASDS lithobraking"],"SET":["Single-Event Transient, spurious radiation discharge through a circuit"],"SFC":["Thrust Specific Fuel Consumption (fuel used per unit thrust)"],"SFNA":["Stable Fuming Nitric Acid, hypergolic oxidizer"],"SHAR":["Sriharikota Range"],"SHLLV":["Super-Heavy Lift Launch Vehicle (over 50 tons to LEO)"],"SHLV":["Super-Heavy Lift Launch Vehicle (over 50 tons to LEO)"],"SIP":["Strain Isolation Pad for Shuttle's heatshield tiles"],"SIRCA":["Silicone Impregnated Reusable Ceramic Ablator"],"SITVC":["Secondary Injection Thrust Vector Control"],"SLC-37":["Space Launch Complex 37, Canaveral (ULA Delta IV)"],"SLC-40":["Space Launch Complex 40, Canaveral (SpaceX F9)"],"SLC-41":["Space Launch Complex 41, Canaveral (ULA Atlas V)"],"SLC-4E":["Space Launch Complex 4-East, Vandenberg (SpaceX F9)"],"SLC-4W":["Space Launch Complex 4-West, Vandenberg (SpaceX F9, landing)"],"SLC40":["Space Launch Complex 40, Canaveral (SpaceX F9)"],"SLCH4":["Slush\/Supercooled Liquid Methane"],"SLM":["[Selective Laser Melting](https:\/\/en.wikipedia.org\/wiki\/Direct_metal_laser_sintering) additive manufacture, also Direct Metal Laser Sintering"],"SLP":["Second Launch Pad at Satish Dhawan Space Centre, operational since 2005"],"SLS":["Space Launch System heavy-lift","Selective Laser Sintering, contrast DMLS"],"SLS-1":["[Exploration Mission 1](https:\/\/en.wikipedia.org\/wiki\/Exploration_Mission_1), Orion capsule; planned for launch on SLS"],"SMAB":["(Former) Solid Motor Assembly Building, Cape Canaveral"],"SMART":["\"Sensible Modular Autonomous Return Technology\", ULA's engine reuse philosophy"],"SMAW":["[Shielded Metal Arc Welding](https:\/\/en.wikipedia.org\/wiki\/Shielded_metal_arc_welding)"],"SMD":["Science Mission Directorate, NASA"],"SN":["(Raptor\/Starship) Serial Number"],"SNC":["Sierra Nevada Corporation"],"SN\\\\d+":["(Raptor\/Starship) Serial Number"],"SOI":["Saturnian Orbital Insertion maneuver","Sphere of Influence"],"SOMD":["Space Operations Mission Directorate, NASA"],"SOP":["Standard Operating Procedure"],"SOX":["Solid Oxygen, generally not desirable","Sarbanes-Oxley US accounting regulations"],"SPAM":["*SpaceX Proprietary Ablative Material* (backronym)"],"SPF":["Single Point of Failure"],"SPICE":["SPectral Imaging of the Coronal Environment, instrument on ESA's Solar Orbiter"],"SPIF":["Spacecraft Processing and Integration Facility, Cape Canaveral (now PPF)"],"SPOF":["Single Point of Failure"],"SPoF":["Single Point of Failure"],"SRB":["Solid Rocket Booster"],"SRP":["Supersonic Retro-Propulsion"],"SS\/L":["Space Systems\/Loral, satellite builder"],"SSAU":["State Space Agency of Ukraine"],"SSBA":["Space Situational Based Awareness"],"SSC":["Stennis Space Center, Mississippi"],"SSH":["Starship + SuperHeavy (see BFR)"],"SSL":["Space Systems\/Loral, satellite builder"],"SSME":["[Space Shuttle Main Engine](https:\/\/en.wikipedia.org\/wiki\/Space_Shuttle_main_engine)"],"SSO":["Sun-Synchronous Orbit"],"SSP":["Space-based Solar Power"],"SSRMS":["Space Station Remote Manipulator System (*Canadarm*)"],"SSRP":["Supersonic Retro-Propulsion"],"SSTO":["Single Stage to Orbit","Supersynchronous Transfer Orbit"],"SSVP":["Sistema Stykovki i Vnutrennego Perekhoda, Russian docking standard"],"STA":["Special Temporary Authorization (issued by FCC for up to 6 months)","Structural Test Article"],"STARLINK":["SpaceX's world-wide satellite broadband constellation"],"STEREO":["Solar TErrestrial RElations Observatory, GSFC"],"STLS":["South Texas Launch Site, Boca Chica"],"STP":["[Standard Temperature and Pressure](https:\/\/en.wikipedia.org\/wiki\/Standard_conditions_for_temperature_and_pressure)","[Space Test Program](https:\/\/en.wikipedia.org\/wiki\/Space_Test_Program), see STP-2"],"STP-2":["[Space Test Program 2](https:\/\/en.wikipedia.org\/wiki\/Space_Test_Program#Upcoming_Activities), DoD programme, second round"],"STP2":["[Space Test Program 2](https:\/\/en.wikipedia.org\/wiki\/Space_Test_Program#Upcoming_Activities), DoD programme, second round"],"STS":["Space Transportation System (*Shuttle*)"],"SUFR":["Straighten Up and Fly Right, weight jettison event during Curiosity EDL"],"SV":["Space Vehicle"],"Sabatier":["Reaction between hydrogen and carbon dioxide at high temperature and pressure, with nickel as catalyst, yielding methane and water"],"Starliner":["Boeing commercial crew capsule [CST-100](https:\/\/en.wikipedia.org\/wiki\/Boeing_CST-100_Starliner)"],"Starlink":["SpaceX's world-wide satellite broadband constellation"],"T\/E":["Transporter\/Erector launch pad support equipment"],"TAL":["[Transoceanic Abort Landing](https:\/\/en.wikipedia.org\/wiki\/Space_Shuttle_abort_modes#Transoceanic_abort_landing)"],"TAN":["[Thrust Augmented Nozzle](http:\/\/selenianboondocks.com\/2007\/11\/thrust-augmented-nozzles\/)"],"TCM":["Trajectory Correction Maneuver"],"TDRS":["(US) Tracking and Data Relay Satellite System"],"TDRSS":["(US) Tracking and Data Relay Satellite System"],"TE":["Transporter\/Erector launch pad support equipment"],"TEA":["[Triethylaluminium](https:\/\/en.wikipedia.org\/wiki\/Triethylaluminium)-[Triethylborane](https:\/\/en.wikipedia.org\/wiki\/Triethylborane), igniter for Merlin engines; spontaneously burns, green flame"],"TEA-TEB":["[Triethylaluminium](https:\/\/en.wikipedia.org\/wiki\/Triethylaluminium)-[Triethylborane](https:\/\/en.wikipedia.org\/wiki\/Triethylborane), igniter for Merlin engines; spontaneously burns, green flame"],"TEA\/TEB":["[Triethylaluminium](https:\/\/en.wikipedia.org\/wiki\/Triethylaluminium)-[Triethylborane](https:\/\/en.wikipedia.org\/wiki\/Triethylborane), igniter for Merlin engines; spontaneously burns, green flame"],"TEB":["[Triethylaluminium](https:\/\/en.wikipedia.org\/wiki\/Triethylaluminium)-[Triethylborane](https:\/\/en.wikipedia.org\/wiki\/Triethylborane), igniter for Merlin engines; spontaneously burns, green flame"],"TEI":["Trans-Earth Injection maneuver"],"TEL":["Transporter\/Erector\/Launcher, ground support equipment (see TE)"],"TFR":["Temporary Flight Restriction"],"TGO":["2016-03-14|(Launch of) Trace Gas Orbiter at Mars, an ESA mission"],"TID":["Total Ionizing Dose of radiation"],"TIG":["[Gas Tungsten Arc Welding](https:\/\/en.wikipedia.org\/wiki\/Gas_tungsten_arc_welding) (or Tungsten Inert Gas)"],"TLA":["Three Letter Acronym"],"TLE":["Two-Line Element dataset issued by NORAD"],"TLI":["Trans-Lunar Injection maneuver"],"TLP":["Third Launch Pad at Satish Dhawan Space Centre (Proposed)"],"TMI":["Trans-Mars Injection maneuver"],"TMT":["Thirty-Meter Telescope, Hawaii"],"TOSC":["Test and Operations Support Contract"],"TPA":["TurboPump Assembly, feeds fuel to a rocket engine"],"TPS":["Thermal Protection System for a spacecraft (on the Falcon 9 first stage, the engine \"Dance floor\")"],"TRL":["Technology Readiness Level"],"TSFC":["Thrust Specific Fuel Consumption (fuel used per unit thrust)"],"TSM":["Tail Service Mast, holding lines\/cables for servicing a rocket first stage on the pad"],"TSTO":["Two Stage To Orbit rocket"],"TT&C":["Telemetry, Tracking and Control communications with a satellite"],"TTBA":["\"Flip This ~~Bi-~~ Booster Around\" boostback burn, part of first-stage landing procedure"],"TVC":["Thrust Vector Control"],"TWR":["Thrust-to-Weight Ratio"],"Thaicom-6":["2014-01-06|F9-008 v1.1 to GTO, re-entry burn attempted"],"Thaicom-8":["2016-05-27|F9-025 Full Thrust, core B1023, GTO comsat; ASDS landing"],"TurkmenAlem52E":["2015-04-27|F9-017 v1.1, GTO comsat"],"UDMH":["Unsymmetrical dimethylhydrazine, liquid hypergolic propellant","[Unsymmetrical DiMethylHydrazine](https:\/\/en.wikipedia.org\/wiki\/Unsymmetrical_dimethylhydrazine), used in hypergolic fuel mixes"],"UF9":["Falcon 9 Full Thrust *or* Upgraded Falcon 9 *or* v1.2"],"UHF":["Ultra-High Frequency radio"],"ULA":["United Launch Alliance (Lockheed\/Boeing joint venture)"],"USAF":["United States Air Force"],"USOS":["United States Orbital Segment"],"VAB":["Vehicle Assembly Building"],"VAFB":["Vandenberg Air Force Base, California"],"VBB":["Very Big Brother (Blue Origin's proposed VTVL vehicle, unknown payload to LEO)"],"VEEGA":["Venus\/Earth\/Earth Gravity Assist"],"VFR":["[Visual Flight Rules](https:\/\/en.wikipedia.org\/wiki\/Visual_flight_rules)"],"VG":["Virgin Galactic"],"VHLV":["Super-Heavy Lift Launch Vehicle (over 50 tons to LEO)"],"VIB":["Vertical Integration Facility"],"VIF":["Vertical Integration Facility"],"VLBI":["Very-Long-Baseline Interferometry"],"VLEO":["V-band constellation in LEO","Very Low Earth Orbit"],"VLT":["Very Large Telescope, Chile"],"VSAT":["Very Small Aperture Terminal antenna (minimally-sized antenna, wide beam width, high power requirement)"],"VSSC":["Vikram Sarabhai Space Centre"],"VTHL":["Vertical Takeoff, Horizontal Landing (*Shuttle*)"],"VTOL":["Vertical Take-Off and Landing"],"VTS":["Vertical Test Stand"],"VTVL":["Vertical Takeoff, Vertical Landing"],"VV":["Visiting Vehicle (visitor to the Station)"],"WDR":["Wet Dress Rehearsal (with fuel onboard)"],"WFIRST":["Wide-Field Infra-Red Survey Telescope"],"WFNA":["White Fuming Nitric Acid, hypergolic oxidiser"],"WSMR":["White Sands Missile Range, New Mexico"],"WSO":["[Weapons Systems Officer](https:\/\/en.wikipedia.org\/wiki\/Weapon_systems_officer)"],"XIPS-25":["[25cm Xenon Ion Propulsion System](https:\/\/en.wikipedia.org\/wiki\/XIPS-25) used on Boeing 702 satellites"],"XIRCA":["SpaceX SIRCA TPS, as [placed in context](\/r\/spacex\/comments\/7p6763\/_\/dsfw57y\/) by brickmack"],"ZBP":["Zero Pre-Breathe (spacesuit and habitat at same pressure"],"ZPS":["Zero Prebreathe Spacesuit"],"ablative":["Material which is intentionally destroyed in use (for example, heatshields which burn away to dissipate heat)"],"apoapsis":["Highest point in an elliptical orbit (when the orbiter is slowest)"],"apogee":["Highest point in an elliptical orbit around Earth (when the orbiter is slowest)"],"apohelion":["Highest point in an elliptical orbit around the Sun (when the orbiter is slowest)"],"autogenous":["(Of a propellant tank) Pressurising the tank using boil-off of the contents, instead of a separate gas like helium"],"biprop":["Rocket propellant that requires oxidizer (eg. RP-1 and liquid oxygen)"],"bipropellant":["Rocket propellant that requires oxidizer (eg. RP-1 and liquid oxygen)"],"blisk":["Portmanteau: [Bladed disk](https:\/\/en.wikipedia.org\/wiki\/Blisk)"],"copv":["[Composite Overwrapped Pressure Vessel](https:\/\/en.wikipedia.org\/wiki\/Composite_overwrapped_pressure_vessel)"],"cross-feed":["Using the propellant tank of a side booster to fuel the main stage, or vice versa"],"crossfeed":["Using the propellant tank of a side booster to fuel the main stage, or vice versa"],"cryogenic":["Very low temperature fluid; materials that would be gaseous at room temperature\/pressure","(In re: rocket fuel) Often synonymous with hydrolox"],"dance floor":["Attachment structure for the Falcon 9 first stage engines, below the tanks"],"dancefloor":["Attachment structure for the Falcon 9 first stage engines, below the tanks"],"deep throttle":["Operating an engine at much lower thrust than normal"],"deep throttling":["Operating an engine at much lower thrust than normal"],"electrolysis":["Application of DC current to separate a solution into its constituents (for example, water to hydrogen and oxygen)"],"granularity":["(In re: rocket engines) Allowing for engine-out capability when determining minimum engine count"],"grid fin":["Compact \"waffle-iron\" aerodynamic control surface, acts as a wing without needing to be as large; also, \"grid fin\""],"grid-fin":["Compact \"waffle-iron\" aerodynamic control surface, acts as a wing without needing to be as large; also, \"grid fin\""],"gridfin":["Compact \"waffle-iron\" aerodynamic control surface, acts as a wing without needing to be as large; also, \"grid fin\""],"high beta":["Times of year when the Earth-Sun line and the plane of orbit are nearly perpendicular"],"hopper":["Test article for ground and low-altitude work (eg. Grasshopper)"],"hydrolox":["Portmanteau: liquid hydrogen\/liquid oxygen mixture"],"hypergolic":["A set of two substances that ignite when in contact"],"iron waffle":["Compact \"waffle-iron\" aerodynamic control surface, acts as a wing without needing to be as large; also, \"grid fin\""],"iron-waffle":["Compact \"waffle-iron\" aerodynamic control surface, acts as a wing without needing to be as large; also, \"grid fin\""],"kerolox":["Portmanteau: kerosene\/liquid oxygen mixture"],"lithobrake":["\"Braking\" by hitting the [ground](https:\/\/en.wiktionary.org\/wiki\/lith-)"],"lithobraking":["\"Braking\" by hitting the [ground](https:\/\/en.wiktionary.org\/wiki\/lith-)"],"mT":["~~Milli-~~ *Metric* Tonnes"],"methalox":["Portmanteau: methane\/liquid oxygen mixture"],"mil spec":["Military Specification"],"milspec":["Military Specification"],"monoprop":["Rocket propellant that requires no oxidizer (eg. hydrazine)"],"monopropellant":["Rocket propellant that requires no oxidizer (eg. hydrazine)"],"periapsis":["Lowest point in an elliptical orbit (when the orbiter is fastest)"],"perigee":["Lowest point in an elliptical orbit around the Earth (when the orbiter is fastest)"],"perihelion":["Lowest point in an elliptical orbit around the Sun (when the orbiter is fastest)"],"pmf":["Propellant Mass Fraction"],"power pack":["Pre-combustion power\/flow generation assembly (turbopump etc.)","Tesla's Li-ion battery rack, for electricity storage at scale"],"powerpack":["Pre-combustion power\/flow generation assembly (turbopump etc.)","Tesla's Li-ion battery rack, for electricity storage at scale"],"prepreg":["[Pre-impregnated composite fibers](https:\/\/en.wikipedia.org\/wiki\/Pre-preg) where the matrix\/binding resin is applied before wrapping, instead of injected later"],"pyrophoric":["A substance which ignites spontaneously on contact with air"],"quess":["Portmanteau: Qualified Guess (common parlance: \"estimate\")"],"rain\\sbirds":["Water deluge system at the launch tower base, activated just before ignition"],"rainbirds":["Water deluge system at the launch tower base, activated just before ignition"],"regen":["A method for cooling a rocket engine, by [passing the cryogenic fuel through channels in the bell or chamber wall](https:\/\/en.wikipedia.org\/wiki\/Regenerative_cooling_\\(rocket\\))"],"regenerative":["A method for cooling a rocket engine, by [passing the cryogenic fuel through channels in the bell or chamber wall](https:\/\/en.wikipedia.org\/wiki\/Regenerative_cooling_\\(rocket\\))"],"retro-propulsion":["Thrust in the opposite direction to current motion, reducing speed"],"retropropulsion":["Thrust in the opposite direction to current motion, reducing speed"],"s\/c":["Spacecraft"],"sabatier":["Reaction between hydrogen and carbon dioxide at high temperature and pressure, with nickel as catalyst, yielding methane and water"],"scrub":["Launch postponement for any reason (commonly GSE issues)"],"tanking":["Filling the tanks of a rocket stage"],"triprop":["Rocket propellant in three parts (eg. lithium\/hydrogen\/fluorine)"],"tripropellant":["Rocket propellant in three parts (eg. lithium\/hydrogen\/fluorine)"],"turbopump":["High-pressure turbine-driven propellant pump connected to a rocket combustion chamber; raises chamber pressure, and thrust"],"ullage":["Small rocket motor that fires to push propellant to the bottom of the tank, when in zero-g"],"waffle iron":["Compact \"waffle-iron\" aerodynamic control surface, acts as a wing without needing to be as large; also, \"grid fin\""],"waffle-iron":["Compact \"waffle-iron\" aerodynamic control surface, acts as a wing without needing to be as large; also, \"grid fin\""]}