Athena acronym list, actively maintained by Jan-Uwe Ness (with input from Matthias Ehle, originally initiated by Jos de Bruijne). A useful X-ray glossary maintained by the XMM-Newton Science Operations Centre can be found here. Additions, corrections, and feedback on the below list is very welcome.
Last updated 13 January 2022, containing 1840 entries; Acronyms.xls
1g Earth's gravity
3E Electrical, Electronic, and Electro-mechanical, sometimes referred to as triple E (components)
A Abell (galaxy cluster)
A Acceptance (testing)
A Analysis
a-C amorphous Carbon
A64 Ariane-6.4 (launcher)
AA Alignment Acceptance
AAD Attitude-Anomaly Detector
AAP Active-Archival Phase
AAT Advanced Analysis Tool
AB Abstract
ABCL As-Built Configuration List
ABS ABSolute
AC Active Cascode
AC Alternating Current
AC Analytical Calculator (within SIMPOSiuM)
AC Anti-Coincidence
ACC ACCelerometer
ACD Anti-Coincidence Detector
ACE Advanced Composition Explorer (spacecraft)
ACO Athena Community Office
ACP Athena Calibration Plan
ACPTF Athena Calibration Plan Task Force
ACS Activity Control Sheet
ACS Attitude Control System
ACSS Athena Common Software System
ACSST Athena Common Software System Team
AD Adjusted Derivative (pulse detection)
AD Analogue to Digital
AD Applicable Document
ADA Athena Data Analysis
ADC Analogue to Digital Converter
ADE Actuator Drive Electronics
ADF Attitude Determination Frame
ADPM Antenna Deployment and Pointing Mechanism
ADR Adiabatic Cooler
ADR Adiabatic Demagnetisation Refrigerator
ADS Airbus Defence and Space
AE ArianEspace
AE Astro-E
AE8/AE9 NASA trapped electron/proton environment models
AFE Analogue Front End
AFM Atomic Force Microscope
AFT Abbreviated Functional Test
AGH Akademia Górniczo-Hutnicza (University of Science and Technology, Kraków)
AGN Active Galactic Nucleus
AH Astro-H
AHEAD (Integrated) Activities in the High Energy Astrophysics Domain
AHEPaM Athena High-Energy Particle Monitor
AI Artificial Intelligence
AIB Analogue Interface Board
AIT Assembly, Integration, and Test
AIT/V Assembly, Integration and Test/Verification
AIV Assembly, Integration, and Verification
AKE Absolute Knowledge Error
AL Acceptance (test) Load
Al Aluminium
ALAT Air Liquide Advanced Technologies
ALBA synchrotron radiation facility in Barcelona, Spain (meaning "€œsunrise")
ALD Atomic Layer Deposition
aLIGO Advanced LIGO
ALM Additive Layer Manufacturing
AMA Athena Mirror Assembly
AMBER Active Monitor Box of Electrostatic Risk (radiation monitor)
AMOLF (instituut voor) Atoom- en MOLecuulFysica (institute for atomic and molecular physics)
AMS Alpha Magnetic Spectrometer (ISS)
AMXP Accretion-powered Millisecond X-ray Pulsar
AO Announcement of Opportunity
AOB All Other Business
AOCS Attitude and Orbit Control Sub-system
AOS Acquisition Of Signal
AP As Proposed
ApC Aperture Cylinder
APC AstroParticule and Cosmologie (Paris)
APDB Athena Parameter DataBase
APE Absolute Performance (Pointing) Error
APEC Astrophysical Plasma Emission Code
APM Ammonia Peroxide Mix
APM Antenna Pointing Mechanism
APME Antenna Pointing Mechanism Electronics
APR Array Power Regulator
APS Active Phase Shift(er)
APS Active-Pixel Sensor
APSW APplication SoftWare
AR Acceptance Review
AR Annual Review
AR Anomaly Review
AR Aspect Ratio (pixel)
AR64 Ariane-6.4 (launcher)
ARB Acceptance Review Board
ARB Anomaly Review Board
ARBEB Athena Red Book Editorial Board
ARCUS Arcus MIDEX Explorer (NASA)
AREMBES Athena Radiation Environment Models and X-Ray Background Effects Simulators (Athena Radiation Environment Modelling Background EStimator)
ARES Analysis and Reporting System
ARF Ancillary Response File
ARSE Angular Resolution Sensitivity Exercise
ASA Athena Science Archive
ASCA Advanced Satellite for Cosmology and Astrophysics
ASCII American Standard Code for Information Interchange
ASDC Athena Science Data Centre
ASE Athena System Engineering (Board)
ASF AREMBES Simulation Framework
ASGS Athena Science Ground Segment
ASH Acquisition and Safe Hold Mode
ASI Agenzia Spaziale Italiana
ASIC Application-Specific Integrated Circuit
ASIE Athena Science Impact Exercise
ASMB Athena System Management Board
ASPHEA Alignment of Silicon Pore optics for High-Energy Astronomy
ASSATF Athena Science Sensitivity Analysis Task Force
ASST Athena Science Study Team
ASST ATHENA Science Support Team
ASST Athena Software and System Team
AST Analysis STep
ASW Application Software
AT AusTria
ATAC Athena Time Allocation Committee
ATB Avionics Test Bench
ATHENA Advanced Telescope for High-ENergy Astrophysics
ATP Authorisation to Proceed
ATSAL ATomic Spectral AnaLysis
ATV Automated Transfer Vehicle
au Astronomical Unit
AV Advanced Variant
aVirgo Advanced Virgo
AVM Avionic Verification Model
AVM AVionics Model
AWG Astronomy Working Group (ESA)
AXB Astrophysical X-ray Background
B Belgium
B-H magnetic induction and magnetic field
B2CD project phases B2, C, and D combined
B4C Boron_4-Carbide
B4N Boron Nitride
BAM Background Analysis Module (SPM/WFI)
BAR Background Assessment Report
BAT BATtery sub-system
BB Bread Board
BBFB BaseBand FeedBack
BCB BenzoCycloButene (coating)
BCDR Battery Charge and Discharge Regulator
BCG Brightest Cluster Galaxy
BCM Battery Charge Management
BCR Battery Charge Regulator
BD Brown Dwarf
BDR Battery Discharge Regulator
BDRF Bi-Directional Reflectivity Function
BE Background Estimate
BEAR Bending magnet for Emission, Absorption, and Reflectivity (beam line)
BEaTriX Beam Expander Testing X-ray facility
BEE Back-End Electronics
BERT BERTini cascade (model)
BESSY Berlin Electron Storage Ring Society for Synchrotron Radiation
BEUR Billion EURo
BF Best Focus
BF Blocking Factor
BGD BackGrounD
BHB Black-Hole Binary
BHC Black-Hole Candidate
BIC BInary Cascade (model)
BIPR Background Intellectual Property Right
BISPO Baffled IXO SPO (mirror module)
BKG BacKGround
BL Boundary Layer
BLWN Band-Limited White Noise
BND Beam-Normalisation Detector
BoE Back of (the) Envelope (calculation)
BoGEMMS Bologna GEant4 Multi-Mission Simulator
BoL Beginning of Life
BoT Beginning of Test
BOT Beginning Of Track
BP Base Plate
Br Bracket (spectral line)
BS BremsStrahlung
BSC Back-SCattering
BSC Bright Star Catalogue
BSCW Basic Support for Cooperative Work
BSE Back-Scattered Electron
BSR Baseline Selection Review
BUSD Billion US Dollar
BUT Brno University of Technology
C (degree) Celsius
C Capacitor
C Carbon
C/B Clamp Band
C&DH Command and Data Handling
CA Conical(-approximation) Athena
CaC Cost at Completion
CaCC Cost-at-Completion Cap
CAD Computer-Aided Design
CAF Contiguous Area Fraction
CAP Cooler Ancillary Panel
CAS Calibration ASsembly (X-IFU)
CAS Czech Academy of Sciences
CATIA Computer-Aided Three-dimensional Interactive Application
CBE Current Best Estimate
CBK Centrum Badań„ Kosmicznych
CBUSH specific element in NASTRAN
CC Cleanliness and Contamination
CC Cold Core (galaxy cluster)
CC Cooling Chain
CC Core Collapse (supernova)
CC Cost-Constrained (mission)
CCB Configuration Control Board
CCCM Channel-Cut Crystal Monochromator
CCCP Cleanliness, Contamination, and Control Plan
CCD Charged Coupled Device
CCD Contract Closure Document
CCDR Closed-Cycle Dilution Refrigerator
CCDS Consultative Committee for Space Data Systems
CCE Cooler Control Electronics
CCGA Ceramic Column Grid Array
CCH Cooler Cryo(genic) Harness
CCM Centre for Concepts in Mechatronics
CCN Change-of-Contract Notice
CCP Component Control Plan
CCP Contamination Control Plan
CCSDS Consultative Committee for Space Data Systems
CCW Counter ClockWise
CD Compact Disc
CD Cool Down
CDA Clean Dry Air
CDE Cooler Drive Electronics
CDF Concurrent Design Facility (ESA)
CDF Cumulative Distribution Function
CDFS Chandra Deep Field South
CDM Code-Domain Multiplexing (Code-Division Multiplexing)
CDMS Command and Data Management Sub-system
CDMU Central Data Management Unit
CDMU Command and Data Management Unit
CDR Critical Design Review
CE Conducted Emission
CE Conformité Européenne
CEA Commissariat à  l'‰Énergie Atomique
CEB CEBreros (35-m ESA ground station near Madrid, Spain)
CELAS specific element in NASTRAN
CER Cost Estimating Relationship
CeSiC Carbon-fiber-reinforced Silicon-Carbide
cf confer / conferatur (compare with)
CF Crest Factor
CFDP CCSDS File Delivery Protocol
CFE Control Front End
CFE Customer-Furnished Equipment
CFEE Cold Front End Electronics
CFEE Cold Front-End Electronics
Cfg Configuration
CFI Customer Furnished Item
CFRP Carbon Fibre Reinforced Polymer
CG Cut Gain
CGH Computer-Generated Hologramme
CH Camera Head (WFI)
CH La CHuisse (Switzerland)
CHT Cylindrical Hall Thruster
CHX Cooler Heat eXchange(r)
CI Configuration Item
CI Conformance Inspection
CIC Connector Identification Code
CIDL Configuration Item Data List
CIL Critical Items List
CIRSOS Collaborative Iterative Radiation Shielding Optimisation System
CLA Cooler (connecting) Line Assembly
CLA Coupled-Load Analysis
CLS Canadian Light Source
CM Chemical Manoeuvre
CM Common Mode
CM Compliance Matrix
CM Consortium Meeting
CM Ministerial Council (meeting)
CMA Cooler Mechanical Assembly
CMA Cost Model Accuracy
CMCU Common Mode Correction Unit
CME Coefficient of Moisture Expansion
CME Coronal Mass Ejection
CMG Control Moment Gyro
CMRR Common-Mode Rejection Ratio
CMZ Central Molecular Zone
CN Change Notice
CN Classical Nova
CNC Computer Numerical Controlled
CND CircumNuclear Disk
CNES Centre National d'Études Spatiales
CO Chief Officer
CoB (X-IFU) Consortium Board
CoB Close of Business
CoC Certificate of Conformance
CODEV Code V optics / ray-tracing simulation software
CoDR Conceptual Design Review
CoG Centre of Gravity
CoM Centre of Mass
COM COMmunication sub-system
ConOps Concept of Operations
CoP Centre of Pressure
CORE Cost-Oriented Reprogramming Exercise (Cost-driven Observation Reprogramming Exercise)
COSPAR Committee On SPAce Research
COTS Commercial Off The Shelf
COVID(-19) COrona VIrus Disease (2019)
CP Calibration Plan
CP Commissioning Phase
CPA Cooler Compressor Assembly
CPD Charged-Particle Diverter
CPF Complex Pupil Function
CPM Central Processing Module
CPPA Coordinated Parts Procurement Agent
CPS Central Plasma Sheet
CPS Chemical Propulsion (Propellant) Sub-system
CPS Counts Per Second
CR Change Request
CR Clean Room
CR Cosine Research
CR Cosmic Ray
CR Count Rate
CR Czech Republic
CRD Calibration Requirements Document
CReMA Consolidated Report on Mission Analysis
CRS Cleanliness Requirement Specification
CRS Coarse Rate Sensor
CRV (time-)Constant Random Variable
CS Conductive Susceptibility
CS Cooling System
CSD Coordinate System Document
CSI Customer Source Inspection
CSL Centre Spatial de Liège
CSS Coarse Sun Sensor
CSS Core Science Survey
CSV Comma-Separated Values
CSW Central SoftWare
CT Compton Thick
CT Core Test
CTA Cherenkov Telescope Array
CTE Coefficient of Thermal Expansion
CTP Core Technology Programme (ESA)
CTQ Critical To Quality
CTR Central Time Reference
CTTS Classical T-Tauri Star
CV Conservative Variant
CV Cosmic Vision (programme of ESA's science directorate)
CV1525 Cosmic Vision Programme 2015 - 2025
CVCM Collected Volatile Condensable Material
CVD Chemical Vapour Deposition
CW Calendar Week
CW ClockWise
CWB Colliding-Wind Binary
CX Charge eXchange
CXB Cosmic X-ray Background
CXC Chandra X-ray observatory Center
CXO Chandra X-ray Observatory
D Design
D Diplexer
D Germany (Deutschland)
DA DopAmine
DAC Digital-to-Analogue Converter
DAQ Data AQuisition
DBRR DCS Breadboarding for Risk Reduction
DC Direct Current
DC Double Cone
DCCM Document Control and Change Manager
DCM Double-Crystal Monochromator
DCR Dedicated Control Room (at ESOC)
DCR Digital Control Room
DCS Demonstrator of the (X-IFU) Cooling System
DCS Detector Cooling System
DD (X-IFU) Dewar Door
DD Double Degenerate
DDF Design Definition File
DDOR Delta Differential One-way Ranging
DDS Data Dissemination System
DDT Director’s Discretionary Time
DDVP Design, Development, and Verification Plan
dE delta Energy (energy resolution)
DE Detector Electronics
DE/EP Digital Electronics/ Events Processing
DEE DE-Excitation Model
DEPFET DEpleted P-channel Field-Effect Transistor
DET Direct Energy Transfer
DF De-Focused
DHS Data-Handling Sub-system
DI De-Ionised
DIL Deliverable Item List
DIW Deionised Water
DJF Design Justification File
DK DenmarK
DLC Diamond-Like Carbon
DLL Design Launch Load
DLL Design Limit Load
DLR Deutsches Zentrum für Luft- und Raumfahrt
DM Demonstration Model
DM Differential Mode
dMCR delta Mission Consolidation Review (2017)
DML Declared Materials List
DMM Design Maturity Margin
DN Dwarf Nova
DNEL Disable Non-Essential Loads
DNM Date of Next Meeting
DOA Degree of Adequacy of the Cost model
DoD Depth of Discharge
DoF Degree of Freedom
DOORS Dynamic Object Oriented Requirements System
DP Data Pack
DP Data Processing
DP Decommissioning Phase
DP Detector Plane
DP Disposal Phase
DP Dowel Pin
DPA Destructive Physical Analysis
DPR Detector-Plane Response
DPR Diffraction plus reflection Pattern from Ray optics
DR DRain current (readout mode)
DRB Delivery Review Board
DRD Document Requirements Description (Definition)
DRE Digital Readout Electronics
DRL Deliverable (Documents) Requirements List
DS Death Star (MM assembly jig)
DS2 Death Star version 2 (MM assembly jig version 2)
DSA Deep Space Antenna
DSL Domain Specific Language
DSMC Direct Simulation Monte-Carlo
DST Deep Space Transponder
DT Dead Time
DT Discretionary Time
DTA Detent high-Torque rotary Actuator
DTCP Daily TeleCommunications Period
DTU DTU Space (formally: National Space Institute, Danish: Institut for Rumforskning og Rumteknologi), part of the Technical University of Denmark (Danmarks Tekniske Universitet)
DUL Design Ultimate Load
DV Delta V(elocity)
DWV Dielectric withstanding voltage
DYL Design Yield Load
E Espana (Spain)
E2E End-to-End
E2EPA End-to-End Performance Assessment (also e2ePA)
EA Effective Area
EAAC Effective-Area Analytical Calculator
EAST ESA Athena Science Team
EAST ESO-Athena Synergy Team
EBB Elegant BreadBoard
EBIT Electron Beam Ion Trap
EC Economic Conditions
eCaC estimated Cost at Completion
ECAP Erlangen Centre for Astro-particle Physics
ECC ESTRACK Control Centre
ECR Earth-Centred Rotating (coordinate system)
ECS EBIT Calorimeter Spectrometer
ECS Environmental Control Sub-system
ECSS European Cooperation for Space Standardization
ECV Exponentially-Correlated Variable
EDI ElectroDeIonisation
EDM Electrostatic Discharge Machining
EEE Electrical, Electronic, and Electromechanical (triple-E)
EF Eigen Frequency
EFR Established Failure Rate
EFU Event Filter Unit
eg exempli gratia (for example)
EGSE Electrical Ground-Support Equipment
EIA Electronic Industries Alliance
EID Experiment Interface Document
EID-A Experiment Interface Document part A
EID-B Experiment Interface Document part B
EIDP End-Item Data Package
EIPS Electron Impact Point Source
EIRP Equivalent Isotropic Radiated Power
ELG Event List Generator
ELP Low-Energy Proton
ELR End-of-Life Review
EM Electrical Model
EM Emission Measure
EM Engineering Model
EMC Electro-Magnetic Compatibility
EMI Electro-Magnetic Interference
EMV(X) Variation of Standard EM package
ENC Equivalent Noise Charge
eNCTS ECLIPSE Non-Conformance Tracking System
EoL End of Life
EOP Extended Operational Phase (also EoP)
EoR Epoch of Reionisation
EoS Equation of State
EoT End of Test
EOT End Of Track
EP Event Processing
EPC Electrical Power Conditioner
EPDM Ethylene propylene diene monomer
EPE External Project Events
EPHIN Electron Proton Helium INstrument
EPIC Energetic Particles and Ion Composition
EPIC European Photon Imaging Camera
EPS Electrical Power (Sub-)system
EQM Engineering and Qualification Model
EQSOL EQuipment Switch-Off Line
EQSR Equipment Qualification Status Review
ERB Energy-Resolution Budget
ERM EPIC Radiation Monitor
ERT Earth Reception Time
ES Electronic Structure
ES Energy Scale
ESA European Space Agency
ESAC European Space Astronomy Centre (Villafranca, Spain)
ESC Electro-Static Chuck
ESCC European Space Components Coordination
ESD ElectroStatic Discharge
ESDC ESAC Science Data Centre
ESHIEM Energetic Solar Heavy Ion Environment Modelling
ESMDB European Space Materials Database
ESOC European Satellite/Spacecraft Operations Centre (Darmstadt, Germany)
ESR Equivalent Serial Resistance
ESR Executive Summary Report
EST ESA Study Team
ESTEC European Space research and TEchnology Centre (Noordwijk, The Netherlands)
ESTRACK European Space TRACKing Network
ESU Energy Storage Unit
ET Einstein Telescope
ETB Electrical Test Bench
EU Electronics Unit
EU European Union
EUV Extreme UltraViolet
EVG EV Group (Electronic Visions Group)
EVT Environmental Verification Test
EW Equivalent Width
EXACRAD Experimental Evaluation of Athena Charged Particle Background from Secondary Radiation and Scattering in Optics
EXAFS Extended X-ray Absorption Fine Structure
F (degree) Fahrenheit
F Filter
F La France
F2F Face-to-Face (meeting); also f2f
FAR Final/Flight Acceptance Review
FAT Factory Acceptance Test
FAU Friedrich Alexander University
FC (WFI) Fast Chip (obsolete, now called FD)
FCM Four Crystal Monochromator
FCT Flight Control Team
FD (WFI) Fast Detector
FD Flight Dynamics (team)
FDDB Flight Dynamics Data Base
FDE Flight Dynamics Engineer
FDIR Failure Detection Isolation and Recovery
FDM Frequency-Domain Multiplexing
FDR Flight Dynamics Room (at ESOC)
FDS Flight-Dynamics System
FDV Fill and Drain Valve
FE Finite Element (model)
FE Front End
FEA Finite-Element Analysis
FEE Front-End Electronics
FeKa Iron K_α (line)
FEM Finite Element Model
FER Frame-Error Rate
FF Full Frame
FFBD Functional Flow Block Diagram
FFOS Formation Flying Optical Sensor
FFT Fast Fourier transform
FFT Full Functional Test
FGS Fine Guidance Sensor
FGSE Fluidic Ground-Support Equipment
FI Finland
FINREF FINancial REForm (framework for costing of ESA activities)
FIR Facility Implementation Review
FITS Flexible Image Transport System
FL Focal Length
FLL Flux-Locked Loop
FM Flight Model
FMC FPGA Mezzanine Card
FMEA Failure Modes and Effects Analysis
FMECA Failure Modes, Effects, and Criticality Analysis
FMS Fixed Metering Structure
FoM Figure of Merit
FOP Flight Operations Plan/Procedure
FOP-SW Flight Operations Software
FoR Field of Regard
FOS Factor Of Safety
FOS Flight Operations Ground Segment
FoV Field of View
FP (Launcher) Flight Programme
FP Final Presentation
FP Focal Plane
FPA Focal Plane Assembly
FPC Flow-Proportional Counter
FPCS Focal-Plane Coordinate System
FPGA Field Programmable Gate Array
FPM Focal-Plane Module (obsolete, now called SIM)
FPM Frame-Processing Module (WFI)
FPP Focal-Plane Platform (obsolete, now called SIP)
FPR Focal-Plane Response
FPS Fine Point Slew Mode
FPT Full Performance Test
FR Final Report/Review
FR-II Faranoff-Riley (type-2) radio galaxy
FRF Frequency Response Function
FRM Fringe Reflection Metrology
FRR Flight Readiness Review
FRT Fringe-Reflection (metrology) Technique
FRW Request for Waiver
FS Feasibility Study
FS Flight Spare (Model)
FS Fused Silica
FSAS Flat Stack Assembly Station
FTA Fault Tree Analysis
FTE Full Time Equivalent
FTF FriTioF (model)
FTIR Fourier Transform InfraRed
FuMo Functional Model
FVI Functional Verification Infrastructure
FVV Fill and Vent Valve
FW Filter Wheel
FW&F Filter Wheel and Filter
FWA Filter-Wheel Assembly
FWV Windowed Variance Filter
FY Fiscal Year
G_ee single-sided power spectral density
G/S Ground Station (also GS)
G/T (Antenna) Gain-to-noise Temperature
GAPHE Groupe AstroPhysique des Hautes Energies (Liège)
GBH Galactic Black Hole
GCR Galactic Cosmic Ray
GDIR General Design and Interface Requirements
GDML Geometry Description Markup Language
GEANT GEometry ANd Tracking
GEANT4 GEometry ANd Tracking version 4
GEO Geostationary Earth Orbit
GF Geometrical Factor
GIM Galvanic Isolation Module
GM Gifford-McMahon (cooler)
GMSK Gaussian Minimum Shift Keying
GMT Greenwich Mean Time
GNC Guidance and Navigation Control
GND GrouND(ing)
GO Guest Observer
GPS Global Positioning System
GRAS GEANT4 Radiation Analysis for Space
GRB Gamma Ray Burst
GRP Giant Radio Pulse
GRR Global Reset Register
GRS Geodetic Reference System
GS Ground Segment
GSDP Ground Safety Data Package
GSE Ground Support Equipment
GSE Gyro Stellar Estimator (sometimes denoted GSTE)
GSFC Goddard Space Flight Center
GSP General Studies Program
GSTP General Support Technology Programme (ESA)
GT Guaranteed Time
GUI Graphical User Interface
GW Gravitational Wave
GXB Galactic (halo) X-ray Background
H Hyperboloid
H_2O Water
H_2O_2 Peroxide
H/K HouseKeeping (data); also HK
H/R Height over Radius (of a disk)
H/W Hardware
HASTR High-Accuracy Star TRacker (sometimes denoted HA-STR)
HDF5 Hierarchical Data Format version 5
HDLC High-level Data Link Control (protocol)
HDRM Hold Down and Release Mechanism
HDRS Hold Down and Release System
HEAPA High-Energy AstroPhysics Association (Japan)
HEO Highly Eccentric/Elliptical Orbit
HEPA High‐Efficiency Particulate Air (filter)
HEU Hot and Energetic Universe
HEW Half-Energy Width (refers to the Point Spread Function)
HF High Frequency
HFSE High-Frequency Spatial Error
HGA High-Gain Antenna
HICP Harmonised Index of Consumer Prices
HiREFS High-Resolution Erect Field Spectrometer
HJ Hot Jupiter
HKTM Housekeeping and Telemetry
HMI Human-Machine Interface
HN HarNess
HP High Precision neutron (model)
HP-STR High-Performance Star TRacker
HPD Half-Power spot Diameter
HPO High Performance Optics (outdated, shall not be used anymore)
HR High-Resolution (event)
HRMA High-Resolution Mirror Assembly (Chandra)
HS Heat Switch
HSC High Speed Cutting
HSIA Hardware-Software Interaction Analysis
HU Heat Up
HV-HPC High-Voltage High-Power Command
HXI Hard X-ray Imager (Hitomi)
HXT Hard X-ray Telescope (Hitomi)
HZB Helmholtz-Zentrum Berlin
HZW Half-Zero Width
I Italia
I-AR Instrument(s) Acceptance Review
I-CDR Instrument(s) Critical Design Review
I-O Inner-Outer (mirror stracks)
I-QR Instrument(s) Qualification Review
I/F InterFace
I2C Inter-Integrated Circuit (also denoted I^{2}C)
IAAT Institut für Astronomie und Astrophysik - Universität Tübingen
IAC Intermediate Alignment Check
IACHEC International Astrophysical Consortium for High-Energy Calibration
IAP (Czech) Institute of Atmospheric Physics
IAPS Istituto di Astrofisica e Planetologia Spaziali
IAS Institut d'Astrophysique Spatiale
IASF Istituto di Astrofisica e Fisica dello Spazio
IBF Ion-Beam Figuring
IC Industrial Contract
IC Instrument Chamber
IC Integrated Circuit
IC Inter-Calibration
ICC Instrument Consortia Consolidation
ICC Instrument Control Centre
ICC Internal Contamination Control
ICD Interface Control Document
ICE Independent Cost Estimate
ICM Intra-Cluster Medium
ICPU Instrument Control and Power(-distribution) Unit
ICS Inner Cold (Cryogenic) Shield (WFI)
ICS Ion Composition Sub-system
ICU Instrument Control Unit
IDL Interactive Data Language
IDM Integrated Design Model
ie id est (in other words)
IE Instrument Efficiency
IEC International Electrical Commission
IEM Instrument Electronics Module
IEM Interplanetary Electron Model
IF Integration Frame
IFC InterFace Controller
IFCA Instituto de Física de CAntabria (CSIC-UC)
IFU Integrated Field Unit
IGM Inter-Galactic Medium
IID Interface Identification Document
IMD IDL based software for modelling the optical properties of multilayer films
IMF Initial-Mass Function
IMP International Monitoring Platform
IMU Inertia Measurement Unit
INAF Istituto Nazionale di Astrofisica
INFLPR (Romanian) National Institute for Laser, Plasma & Radiation Physics
INS Isolated Neutron Star
INVAR INVARiable, a particular Nickel–Iron alloy with 36% Nickel and 64% Iron (FeNi36 or 64FeNi)
IO Inputs and Outputs
IOC In-Orbit Commissioning
IOCR In-Orbit Commissioning Review
IP In-Plane
IP Intermediate Polar
IP Intersection Plane
ip Primary stack of the Inner XOU in a MM
IPA IsoPropyl Alcohol (cleaner)
IPC Industrial Policy Committee (ESA)
IPCS Inner Passive Cold (Cryogenic) Shield
IPM Integrated Progress Meeting
IPR Intellectual Property Right
IPRAM Interplanetary and Planetary Radiation Model (for human spaceflight)
IPRR Instrument(s) Preliminary Requirements Review (2018/2019)
IQM Inherent Quality of the cost Model
IR Infra Red
IR Interim Review
IRAP Institut de Recherche en Astrophysique et Planétologie
IRB InfraRed Background
IRD Interface Requirements Document (Definition)
IRS Institut für Raumfahrtsysteme (Stuttgart)
IS Inner Stack
is Secondary stack of the Inner XOU in a MM
ISC Instrument Science (and data) Centre
ISCO Innermost Stable Circular Orbit
ISEE-3 International Sun/Earth Explorer 3 spacecraft
ISL In-band Spurious Level
ISM Instrument Switch Mechanism
ISO International Organisation for Standardisation (Geneva, Switzerland)
Isp Specific Impulse
ISR Intermediate Status Review
ISS International Space Station
ISV Independent Software Validation
ISVV Independent Software Verification and Validation
IT Instrument Team
ITAR International Traffic In Arms Regulation (USA)
ITC Instrument Team Centre
ITO Interface Technical Officer
ITT Invitation To Tender
ITU International Telecommunications Union
IWF Institut für Weltraumforschung (Graz, Austria)
IWS Instrument WorkStation
IxI Interface versus (times) Interface (diagram / matrix)
IXO International X-ray Observatory
IXPE Imaging X-ray Polarimetry Explorer (NASA)
J Japan
JASRI Japan Synchrotron Radiation Research Institute
JAXA Japanese Aerospace eXploration Agency
JD Julian Date
JD Justification Document
JFY Japanese Fiscal Year
JIRA issue tracking product (not an acronym, but a truncation of Gojira, the Japanese name for Godzilla)
JT Joule-Thomson (cooler)
JT2K Joule-Thomson Two Kelvin (cooler)
JTAG Joint Test Action Group (reprogramming interface)
K Kelvin
KA acceptance (test) factor
Ka Kapton
KDE Knowledge Drift Error
KDP Key Decision Point (NASA)
kE kilo-Euro
KEK High-Energy Accelerator Research Organisation (Japan)
KH Kelvin-Helmholtz
KIP Key Inspection Point
Km model (margin) factor
Kmp margin-policy factor
KO Kick Off
KOH Potassium Hydroxide
KOM Kick-Off Meeting
KOU KOUrou ground station (French Guiana)
KP Key Point
KP Key Programme (Project)
Kp project (margin) factor
KPI Key Performance Indicator
KQ qualification (test) factor
KRE Knowledge Reproducibility Error
ks kilo-second
kSZ kinetic Sunyaev-Zeldovitch (effect)
L_bol Bolometric Luminosity
L_edd Eddington Luminosity
L/P Low Pressure
L/V Launch Vehicle (also LV)
L0 Level-0 (data)
L1 First Lagrange libration point of the Earth-Moon / Sun system
L1 First Large mission of the ESA Cosmic Vision 2020 programme (assigned to JUICE)
L1 Level-1 (data)
L2 Libration Point 2 (on anti Sun side of Earth)
L2 Second Large mission of the ESA Cosmic Vision 2020 programme (assigned to Athena)
L3 Level-3 (data)
L3 Third Large mission of the ESA Cosmic Vision 2020 programme (assigned to LISA)
LA (WFI) Large Array (obsolete, now called LDA)
LAM Laser Additive Manufacturing
LAN Local Area Network
LAT Lot Acceptance Test
LBF Long-Beam Facility
LC inductor (L) and capacitor (C)
LC Load Case
LCL Latch Current Limiter
LD (WFI) Large Detector (one quadrant of the WFI LDA)
LDA (WFI) Large Detector Array
LDCP Low-Density Parity-Check (code)
LDS Laser Displacement Sensor
LEAF Large European Acoustic Facility (ESTEC)
LEAS List of ESA Approved Standards
LED Light Emitting Diode
LEO Low Earth Orbit
LEOP Launch and Early-Orbit Phase
LET Linear Energy Transfer
LFA Lead Funding Agencies
LFSE Low-Frequency Spatial Error
LG Linear Gain
LGA Low-Gain Antenna
LHEP Low and High Energy Parameterised (model)
LHP Loop Heat Pipe
LIGO Laser Interferometer Gravitational-wave Observatory
LIP LIssajous Pointing
LIS Local Interstellar Spectrum
LISA Laser Interferometer Space Antenna
LISN Line Impedance Stabilisation Network
LIT Listen-In Test
LKE L.K. Engineering
LL Launch Lock
LL Limit Load
LLA Launch-Lock Assembly
LLBL Low-Latitude Boundary Layer
LLI Long Lead Item
LLNL Lawrence Livermore National Laboratory
LMCO Lockheed Martin COrporation
LMJ Laser Micro-(water) Jet (cutting)
LNA Low-Noise Amplifier
LoC Lines of Code
LoE Letter of Endorsement
LoR Level of Resources (ESA speak for money)
LoS Letter of Support
LoS Line of Sight
LOS Loss Of Signal
LOSF Line-Of-Sight Frame
LOSSAA Line-of-Sight to Sun Aspect Angle
LOSTF Line-Of-Sight Target Frame
LPA Large Pixel Array
LPTC Large Pulse-Tube Cooler
LR Low-Resolution (event)
LRR Launch Readiness Review
LS Launch(er) Segment
LS Lower Section (of FMS)
LSA Launch Service Agreement
LSB Least Significant Bit
LSD Linear Spectral Density
LSF Line-Spread Function
LSFE Low Spatial-Frequency Error
LSRU Low Shock Release Unit
LT Laser Tracker
LTD Low-Temperature Detector (conference)
LTP Long-Term Proposal (SPring-8)
LURE Laboratoire d'Utilisation du Rayonnement Électromagnétique
LUT Look-Up Table
LVA Launch Vehicle Adapter
LVD Low Voltage Directive
LVDS Low-Voltage Differential Signalling
LVT Lot Validation Testing
LW Launch Window
LXB Local (bubble) X-ray Background
M^2 Excess noise in X-IFU energy resolution
M55J Ultra-high modulus carbon fibre
MA Mirror Assembly
MA Mirror Axis
MA Mission Analysis
MACS MAssive Cluster Survey
MAD Mirror-Assembly Demonstrator
MAF Mirror-Assembly Frame
MAIT Manufacturing, Assembly, Integration, and Test (also MAIVT)
MAL MALindi ground station (Kenya)
MAM Mirror Assembly Module
MAMD Mirror Assembly Module Demonstrator
MAR Mission Adoption Review
MASD Median Axial Slope Deviation
MAXI Monitor of All-sky X-ray Image
MBD Mission Budgets Document
MC Mirror Cover
MC Monte Carlo
MCA Mirror-Cover Assembly
MCD Modified Condition and Decision
MCEM Mirror-Cover Ejection Mechanism
MCF Mirror Calibration Facility
MCI Mass, Centre-of-gravity, and Inertia
MCM Multi-Chip Module
MCP Mirror Calibration Plan
MCR Main Control Room (at ESOC)
MCR Mission Consolidation Review (2016)
MCS Mission Control System
MCV Magnetic Cataclysmic Variable
MD Magnetic Diverter
MD Mass Dummy
MD Mirror Demonstrator
MDR Mission Definition Review
MDR Model Development Review
MEA Main Error Amplifier
MEKAL Rolf Mewe, Jelle Kaastra, and Duane Liedahl (atomic database and name of spectral model)
MEM Meteoroid Engineering Model
MEMS Micro Electrical Mechanical System
MEUR Million EURo
MFP Mean Free Path
MFR Mission Formulation Review (2019)
MFT Micro Finish Topographer
mgmt ManaGeMenT
MGSE Mechanical Ground Support Equipment
MGU Motor Gear Unit
MHD Magneto-Hydro Dynamics
MHI Mitsubishi Heavy Industries
MIABWG Milano-IASF Athena Background Working Group
MIB Minimum Impulse Bit
MIB Mission Information data Base
MICD Mechanical Interface Control Drawing
MIL United States of America Department of Defence Standard
MIM Metal-Insulator-Metal
MIP Mandatory Inspection Point
MIP Minimum Ionising Particle
MIP Movable Instrument Platform (obsolete)
MIP Moveable Instrument Platform
MIRD Mission Implementation Requirements Document
MIST Mechanical Integrated Services and Technologies (GSFC)
MIXS Mercury Imaging XRay Spectrometer
MJD Modified Julian Date
MKE Mean Knowledge Error
ML Machine Learning
ML Multi-Layer (coating)
MLA Multi-Lateral Agreement
MLG MaLarGüe ground station (35-m ESA ground station in Argentina)
MLI Multi-Layer Insulation
MLT Media Lario Technologies
MM Mirror Module
MMA Movable Mirror Assembly
MMA Moveable Mirror Assembly
MMIC Microwave Monolithic Integrated Circuit
MMPDS Metallic Materials Properties Development and Standardisation
MMPP Materials, Mechanical Parts, and Processes
MMU Mass Memory Unit
Mngt Management
MO (CCSDS) Mission Operations (Services)
MoA Memorandum of Agreement
MOA Mirror Optical Axis
MOC Mission Operations Centre (ESA)
MOC Molecular Organic Contamination
MOI Mission Operations Infrastructure
MOI Moment Of Inertia (also MoI)
MOIS Mission Operations Information System
MoM Minutes of Meeting
MOP Mock Observing/Observation Plan
MoS Margin of Safety
MOS Metal Oxide Semiconductor
MOS Mock Observing Sequence
MOSFET Metal–Oxide–Semiconductor Field-Effect Transistor
MOT Mock Observing Timeline
MoU Memorandum of Understanding
MPCB Materials, Mechanical Parts, and Processes Control Board
MPE Max-Planck-Institut für Extraterrestrische Physik
MPE Mean Performance Error
MPG Max-Planck Gesellschaft
MPG/HLL Max-Planck-Gesellschaft/HalbLeiterLabor (semiconductor laboratory)
MPLS Multi-Protocol Label Switching
MPPT Maximum Power Point Tracker/Tracking
MPS Max-Planck Society
MPS Mission-Planning System
MPTC Miniature Pulse-Tube Cooler
MPWG Mission Performance Working Group
MR Medium-Resolution (event)
MRD Mission Requirements Document
MRR Manufacturing Readiness Review
MRR Mission Readiness Review
MRT Mission Readiness Test
MS (ESA) Member State
MS MagnetoSheath
Ms Mega-second
MS MicroSoft
MS Mirror Structure
MSB Most Significant Bit
MSBL MagnetoSheath Boundary Layer
MSC/NASTRAN Software for finite-element analysis
MSFC Marshall Space Flight Center
MSPS Mega Symbols per Second
MSR Mission Selection Review
MSS Mirror SunShield
MSSA Mirror SunShield Assembly
MSSDM Mirror SunShield Deployment Mechanism
MT Mission Time
MTBF Mean Time Between Failure
MTH Mechanical-THermal (testing)
MTL Mission Time Line
MTTR Mean Time To Repair
MUSD Million US Dollar
MUST Mission Utility and Support Tools
MUX MUltipleXing (factor)
MV Multi-Variant
MW Multi-Wavelength
MXS Modulated X-ray Source
N Nominal
N/C Normally Closed
N/m Newton per meter
N+R Nominal plus Redundant
NASA National Aeronautics and Space Administration
NAST NASA Athena Science Team
NC Non-Compliant
NCA Nickel-Cobalt-Aluminium
NCD Network Configuration Document
NCR Non-Conformance Report
NCTS Non-Conformance Tracking System
NDA Non-Disclosure Agreement
NDIU Network Data Interface Unit
NEA Noise Equivalent Angle
NEA Non-Explosive Actuator
NED NASA/IPAC Extragalactic Database
NEP Noise-Equivalent Power
NFI Narrow-Field Imaging
NGRM Next-Generation Radiation Monitor (ESA)
NH_4OH Ammonia Hydroxide
NHXM New Hard X-ray Mission
NID Non-Ionising Dose
NIEL Non-Ionising Energy Loss
NIR Near Infra-Red (wavelength)
NIS Network Interface System
NIST National Institute of Standards and Technology
NL NetherLands
NLS Narrow-Line Seyfert (galaxy)
NM Neutron Monitor
Nm Newton meter
NMOS N-type Metal-Oxide Semiconductor
NNO New NOrcia (35-m ESA ground station near Perth, Australia)
NOP Network Operations Procedure
NOP Nominal Operational Phase
NPMC National Project Manager Committee
NPSL NASA Parts Selection List
NRB Non-Conformance Review (board)
NS Neutron Star
NSLS National Synchrotron Light Source (Brookhaven National Laboratory)
NVR Non-Volatile Residue
NXB Non-X-ray (i.e., particle) Background
OAB Osservatorio Astronomico di Brera
OAPA Osservatorio Astronomico di PAlermo
OAR Open Area Ratio
OAT Off-Axis Test
ObAS Observatoire Astronomique de Strasbourg
OBC On-Board Computer
OBCP On-Board Control Procedure
OBDH On-Board Data Handling
OBF Optical Blocking Filter
OBM On Board Metrology
OBMS On-Board Metrology Sensor
OBMT On-Board Metrology Target
OBS On-Board Software (also OBSW)
OBSM On-Board Software Maintenance
OBT On-Board Time
OCC Operations Control Centre
OCDT Open Concurrent Design Tool
OCM Orbit-Control Manoeuvre
OCP Optics Calibration Plan
OCS Outer Cold Shield (WFI)
OD Overall Diameter
ODF Observation Data File (XMM-Newton)
ODI Open Data Interface
OF Obscuration Factor
OFDR Optical Frequency-Domain Reflectometry
OFHC Oxygen-Free High-conductivity Copper
OGB Out Gassing Baffle
OGS Operational Ground Segment
OGSE Operations(Optical) Ground Support Equipment
OH Optical Head
OIRD Operations Interface Requirements Document
OM Optics Module
OMA Opto-Mechanical Assembly
OMADA Opto-Mechanical And Detector Assembly
OMC On-Model Centroid
OMF On-board Metrology Frame
OOF Out Of Focus
OoM Order of Magnitude
OOP Out-Of-Plane
op Primary stack of the Outer XOU in a MM
OPD Optical Path Difference
ORATOS ORbit and ATtitude Operations System
ORR Operational Readiness Review
OS Outer Stack
os Secondary stack of the Outer XOU in a MM
OSG Observatory Science Goal
OSG Observing Sequence Generator (generates observing sequence from MOP)
OSR Optical Solar Reflector
OT Open Time
OTAC Observation Time Allocation Committee
OTF Optical Transfer Function
OTS Off-The-Shelf (component)
OU Open University
OUTER Outer-radius SPO TDA
OV Outer Vessel
P Paraboloid
P Portugal (sometimes erroneously used for Poland)
P_c confidence level
P_ee linear spectral density
P-H Paraboloid-Hyperboloid
P-S Primary-Secondary (mirror stacks)
p-v peak-to-valley
P/F Pass/Fail
P/F PlatForm (also PF)
P/L PayLoad (also PL)
PA Product Assurance
PAC PArticulate Contamination
PaCSXI Passive Cryogenic SIM/X-IFU Interface (working group)
PAD Parts Approval Document
PAL Project Authorisation Letter (NASA)
PAMELA Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics
PAN Penetrating particle ANalyser
PANTER PAntolsky Neuried TEstanlage Röntgen
PAP Product Assurance Plan
PARD Product Assurance (and safety) Requirements Document
PARS Product Assurance Requirements Specification
PAU Pattern Analyser Unit
PB Pencil Beam
PBH Primordial Black Hole
PC Pre-Cooling (point)
PCA Principal Component Analysis
PCB Parts Control Board
PCB Printed Circuit Board
PCDU Power conditioning and distribution unit
PCLA Preliminary Coupled-Load Analysis
PCM Power Conditioning Module
PCM Pressurised Cargo Module
PCN Process Change Notice
PCOS Physics of the COSmos (NASA)
PCP Programmatic and Cost (review) Panel
PCS Physical Coding Sublayer
PCS Primary Coordinate System
PCU Pixel Correction Unit
PDA PolyDopAmine
PDCU Power Distribution Control Unit
PDD Payload Definition/Description Document
PDE Performance Drift Error
PDF Portable Document Format (Adobe Acrobat)
PDHU Payload and Data Handling Unit
PDHU Payload Data-Handling Unit
PDR Preliminary Design Review
PDU Power Distribution Unit
PEA Project Experiment Arrangement (PRODEX)
PEC Pointing-Error Contributor
PEE Pointing-Error Engineering
PEEH Pointing Error Engineering Handbook
PEEK PolyEther Ether Ketone (plastic/polymer)
PEET Pointing Error Engineering Tool
PEPS Power system modelling tool developed by ESA TEC-EP
PER Process and Equipment Review
PES Pointing-Error Source
PET Photon-Event Table
PFM Proto-Flight Model
PGSE Pressure Ground Support Equipment
Ph Phase
PH Pulse Height
PHA Pulse Height Amplitude
PhAx Phase-A eXtension
PHU Partial Heat Up
PI Photon Ionisation
PI Polyimide
PI Principal Investigator
PI Pulse Integral
PID Process Identification Document
PID Proportional Integral Derivative
PIF Proton Irradiation Facility (at PSI)
PIND Particle Impact Noise Detection
PIXE Particle-Induced X-ray Emission
PLA PayLoad Adaptor
PLF PayLoad Fairing
PLF PLatForm
PLP Pre-Launch Phase
PM Progress Meeting
PM Project Manager
PMD Propellant Management Device
PMF Probability Mass Function
PMOS P-type Metal-Oxide Semiconductor
PMP Parts, Materials, and Processes
PN Pseudo-Noise (ranging)
PO Pressure Oscillation
PO Product Owner
PoC Point of Contact
POE Project Owned Events
POL Point-Of-Load
POP Post-Operations Phase
POPS Post-OPerationS Phase
POS Preferred Observation Sequence
PPBE Planning, Programming, Budgeting, and Execution (NASA)
ppm parts per million
PPR Performance and Process Review
PPRR Payload PRR
PPS Pulse Per Second
ppt parts per trillion
PR Preliminary Review
PR1 Progress Review #1
PRD (X-IFU) Performance Requirements Document (obsolete)
PRD Project Reference Database
PRE Performance Reproducibility Error
PRE Programmable Real-time Emulator
PRECO PRE-COmpound Model
PRESPO PReparation of the Engineering model of the SPO optics (continuation of SPOHO)
ProdEx PROgramme de Développement d'Expériences scientifiques (ESA)
PRR Preliminary Requirements Review
PS Plasma Sheet
PS Primary Structure
PS Project Scientist
PSBL Plasma Sheet Boundary Layer
PSC Partner Science Centre
PSD Power Spectral Density
PSF Planning Skeleton File
PSF Point Spread Function
PSI Paul Scherrer Institute
PSO Polished Silicon Optics
PSPC Position Sensitive Proportional Counter
PSR Project Support Room (at ESOC)
PSU Power Supply Unit
PT Product Tree
PT Pulse Tube
PTB Physikalisch-Technische Bundesanstalt
PTC Pulse-Tube Cooler
PTF Palomar Transient Factory
PTFE PolyTetraFluoroEthylene (Teflon)
PTR Post Test Review
PU Partner User (SPring-8)
PUS Packet Utilisation Standard/Service(s)
PV Performance Verification
PVP Performance Verification Phase
PW Plain Weave
PWN Pulsar-Wind Nebula
PWS Plain Weave Spread
Q Qualification (testing)
QA Quality Assurance
QCI Quality Conformance Inspection
QCM Quartz Crystal Microbalance
QDR Quick-Dump Rinse
QE Quantum Efficiency
QGS Quark Gluon String (model)
QIV Quality of the Input Values
QL Qualification Load
QLA Quick-Look Analysis
QM Qualification Model
QML Qualified Manufacturers List
QR Qualification Review
QRR Qualification Review Report
QSL Qualification Status List
QSL Quasi-Static Load
R Redundant
R Resistor
R Review (of design)
R_n normal Resistance
R1500 Outer-radius mirror module
R200 Radius at which the mean mass density exceeds the critical density by a factor of 200
R277 Inner-radius mirror module
R500 Radius at which the mean mass density exceeds the critical density by a factor of 500
R737 Middle-radius mirror module
RACI Responsible / Accountable / Consulted / Informed (matrix)
RADLAT RADiation Lot Acceptance Test
RAL Rutherford Appleton Laboratory
RAM Random-Access Memory
RaMCaF Rainwater Memorial Calibration Facility
RAMS Reliability Availability Maintainability and Safety
RAS Rotating Anode Source
RASS ROSAT All Sky Survey
RB Red Book
RB Requirements Baseline
RC Resistor Capacitor
RCA Radio Corporation of America (laboratories)
RCS Reaction Control (Sub-)system
RD Reference Document
RDM Radiation Design Margin
RE Radiated Emission/Emissivity
REL (SEPEM) Reference Event List
RF Radio Frequency
RFC Radio Frequency Compatibility
RFCT Radio Frequency Compatibility Test
RFD Request For Deviation
RFDU Radio Frequency Distribution Unit
RFI Request For Information
RFQ Request For Quotation
RFW Request For Waiver
Rg Gravitational (Schwarzschild) radius
RH Relative Humidity
RHA Radiation Hardness Assurance
RID Review Item Discrepancy
RIKEN Rikagaku Kenkyūsho (research institute in Japan)
RIU Remote Instrument Unit
RJ Rotary Joint
RJF Requirements Justification File
RKE Relative Knowledge Error
RMAP Remote Memory Access Protocol
RMF Redistribution (Response) Matrix File
RML Recovered Mass Loss
RMS Root Mean Square
RMU Rate Measurement Unit
RMXP Rotation-powered Millisecond X-ray Pulsar
RN Recurrent Nova
RO Reverse Osmosis
ROM Read-Only Memory
ROM Rough Order of Magnitude
RP Random Process
RPB RTU Power Board
RPE Relative Performance Error
RPSD Root Power Spectral Density
RR Readiness Review
RS Radiative Susceptibility
RS Raster Scan
RS Reed-Solomon
RS485 Recommended Standard 485
Rsh shunt Resistor
RSP ReSPonse (file)
RSS Root Sum Square/Squaring
RST (Marangoni) Ring-Tread System (dryer)
RSU Read-Shutter Unit
RT Radiative Transfer
RT Ray Tracing
RT Real-Time
RT Remote Terminal
RT Room Temperature
RTD Reference Telescope Design/Document
RTE Real-time Emulator
RTG4 Reprogrammable, radiation-tolerant FPGA from Microsemi
rtHz square root of Hertz
RTPU Remote Thermal and Power Unit
RTS Rotating Target Source
RTU Remote Instrument Unit
RV Random Variable
RVT Radiation Verification Testing
RW Reaction Wheel
RWA Reaction-Wheel Assembly
RWE Reaction-Wheel Electronics
Rx Rotation around the x-axis
RXTE Rossi X-ray Timing Explorer
Ry Rotation around the y-axis
Rz Rotation around the z-axis
S Sweden
S-K Sulphur K (line)
S/B Signal to Background (ratio)
S/C SpaceCraft (also denoted SC)
S/S SpreadSheet
S/S Sub-System
S3R Sequential Switching Shunt Regulator
SA Solar Array
SA Sun Acquisition
SAA Solar-Aspect Angle
SAC Self Anti-Coincidence
SADE Solar-Array Drive Electronics
SADM Solar-Array Drive (Deployment) Mechanism
SADS Solar Array Deployment System
SAOM Solar-Array Orientation Mechanism
SAS Sun-Acquisition Sensor
SAST SKA-Athena Synergy Team
SAT Site Acceptance Test
SB Super Bubble
SBT Service des Basses Températures
SC SpaceCraft (also denoted S/C)
SC Steering Committee
SCC Stress Corrosion Cracking
SCCM Standard Cubic Centimeters per Minute
SCF Software Configuration File
SCI SCIence Directorate (of ESA)
SCIOBJ SCIence OBJective
SciRD Science Requirements Document
SCJ Science Council of Japan
SCOM SCience Operations Manager
SCRACS SpaceCraft Reference Attitude Coordinate System
SCSB Space Components Steering Board
SD Single Degenerate
SD Space Debris
SD Stealth Dicing
SDC Science Data Centre
SDD Silicon Drift Detector
SDE Software Development Environment
SDF System Design File
SDMP Space-Debris Management/Mitigation Plan
SDP Science Demonstration Phase
SDPT Science Data Processing Team
SDR Software Design Review
SDS Science Data Server (at ESOC)
SEB Single-Event Burn-out
SEB System Engineering Board
SED Spectral Energy Distribution
SEDR Single-Event Dielectric Rupture
SEE Single-Event Effect
SEFI Single-Event Functional Interrupt
SEGR Single-Event Gate Rupture
SEL Single-Event Latch-up
SEL Sun-Earth Libration (point)
SEL1 Sun-Earth Lagrange/Libration point 1
SEL2 Sun-Earth Lagrange/Libration Point 2
SEP Soft-Energy Proton
SEP Solar Energetic Particle (event)
SEP System Engineering Plan
SEPEM Solar Energetic Particle Environment Modelling
SEPP Science Exploitation and Preservation Platform
SES Sun-Earth-Satellite/Spacecraft (angle)
SET Single-Event Transient
SEU Single-Event Upset
SF Source Follow (readout mode)
SFR Star-Forming Region
SFT Short Functional Test
SFT System Functional Test
SG Science Goal
SGD Soft Gamma-ray Detector (Hitomi)
SGICD Space-to-Ground Interface Control Document
SGO Slumped-Glass Optics
SGS Science Ground Segment
SH Sun Hold
SI International System (of units)
Si Silicon
SI Single Issue
SIB " Science Instruments Bench (""core"" of the SIM, for instance without radiators)"
sic sic erat scriptum (thus was it written)
SiC Silicon-Carbide
SICO Science Impact of COst saving-options exercise (CORE exercise at X-IFU level)
SIM Science Instruments Module
SIMPOSiuM SIMulation of Pore OpticS and Modeling
SIMPUT SIMulation inPUT (for SIXTE)
SIP Science Implementation Plan
SIP Science Instruments Platform
SIRD Science Implementation Requirements Document
SIRENA Software IFCA for Reconstruction of EveNts for Athena X-IFU
SIS Satellite Interface Simulator
SISO Single-Input, Single-Output
SITU Sci(ence)-op(eration)s technical Information Technology Unit (ESAC)
SIXTE SImulation of X-ray TElescopes
SKA Square-Kilometre Array
SKM Station Keeping Manoeuvre
SLAC Stanford Linear Accelerator Center (now known as SLAC National Accelerator Laboratory)
SLI Single Layer Insulation
SM Structural Model
SMAC company in the field of shock and vibration control
SMBH Super Massive Black Hole
SMD Study Management Document
SME Small or Medium(-sized) Enterprise
SMP Science Management Plan
SMP Study Management Plan (obsolete, superseded by Study Management Document)
SN Science Nugget (ACO)
SN SuperNova
SNR Signal-to-Noise Ratio
SNR SuperNova Remnant
SNR Surface Normal Rotation (monochromator)
SOAD Science Operations Assumptions (Agreements) Document
SOC Science Operations Centre (ESA)
SoC State of Charge
SoC Status of Compliance
SOCCI Science Operations Configuration Control Infrastructure
SOCD Science Operations Concept Document
SOHO SOlar Heliospheric Observatory
SOLEIL Source Optimisée de Lumière d'Énergie Intermédiaire du LURE
SOM Spacecraft Operations Manager
SOVT System Operations Validation Test
SoW Statement of Work
SP Soft Proton (from the Sun)
SP Stopping Power
SPA Slice Pattern Analyser
SPA Small Pixel Array
SpaCon Spacecraft Controller (also SPACON)
SPC Science Programme Committee (ESA)
SPE Solar Particle Event
SPENVIS SPace ENVIronment, effects, and education System
SPEX SPEctral X-ray (and UV modelling and analysis tool)
SPF Single Point Failure
SPI Star-Planet Interaction
SPIRIT Silicon Pore Inner RadIus Tender (Inner-radius SPO TDA)
SPM Science Products Module (WFI)
SPM Soft-Proton Monitor
SPO Silicon Pore Optics
SPORT Silicon Pore Optics Ray-tracing Tool
SPORT Silicon-Pore-Optics Rugidisation (and environmental) Test(ing activity)
SPR Software Problem Report
SPring-8 Super Photon ring-8 GeV
SpW Space Wire (bus protocol)
SPW SpaceWire
SQR Simulator Qualification Review
SQUID Semiconducting Quantum Interface Device
SQUID Superconducting QUantum Interference Device
SR Status Review
SR1 Status Review number 1
SR2 Status Review number 2
SRD SC Requirements Document
SRD Spacecraft Requirements Document
SRD System Requirements Document
SRE Science and Robotic Exploration directorate (obsolete, now called SCI)
SREM Standard Radiation Environment Monitor
SRF Software Reuse File
SRG Spectrum - Roentgen - Gamma
SRIM Stopping and Range of Ions in Matter
SRON Stichting RuimteOnderzoek Nederland (Netherlands Institute for Space Research)
SRP Solar Radiation Pressure
SRR Systems Requirements Review
SRS Shock Response Spectrum
SS Single Scattering
SS Sub-System
SSAC Space Science Advisory Committee (ESA)
SSC Senior Survey Committee (for ESA's L-class missions)
SSC Synchrotron Self Compton
SSCE Sun-SpaceCraft-Earth (angle)
SSD Solid-State Detector
SSDE Sun Shield Drive Electronics
SSDM Sun Shield Deployment Mechanism
SSEWG Solar-System Exploration Working Group (ESA)
SSM Second Surface Mirror
SSS Super-Soft (X-ray) Source
SST Science Study Team
SST Solid-State Telescope
SSTR Science Star TRacker
ST Science Team
ST Specification Tree
STA STAbility
STAR Space Technology and Astrophysics Research (Liège)
STC (Ground) STation Computer
STC Single Threshold Processing (pulse detection)
STDM Spacecraft Trajectory Data Message
STEP Standard for the Exchange of Product Data
STFC Science and Technology Facilities Council
STI Supra-Thermal Ion
STM Structural Thermal Model
STOP Structural, Thermal, and Optical Performance
STR Star TRacker
STR STRucture
STT Science Topic Team
STT STar Tracker
SUM Software User Manual
SVF Software Validation Facility
SVM SerVice Module
SVS Spacecraft Venting Sub-system
SVT System Validation Test
SVVP Software Validation and Verification Plan
SW Software
SW Solar Wind
SWCX Solar Wind Charge eXchange
SWG Science Working Group
SWP Synergy White Paper
SWR SpaceWire Router
SXI Soft-X-ray Image (Hitomi)
SXRB Soft X-Ray Background
SXS Soft-X-ray Spectrometer (Hitomi)
SXT Soft-X-ray Telescope (Hitomi)
SZ Sunyaev-Zeldovitch (effect)
T Test
T/O Trade-Off
T0 Launch
TAA Technical Assistance Agreement
TAC Time Allocation Committee
TAI International Atomic Time
TAI Time Atomic International
TAM Transient Analysis Module (SPM/WFI)
TAS Thales Alenia Space
TAS-F Thales Alenia Space France
TAS-I Thales Alenia Space Italy
TB Thermal Balance
TBC To Be Confirmed
TBD To Be Defined
TBS To Be Specified
TBW To Be Written
TC Telecommand(ing)
TC Thermal Cycling
TCB Barycentric Coordinate Time
TCI Technology Conformance Inspection
TCM Trajectory (Transfer) Correction (Control) Manoeuvre
TCM Transfer Correction Manoeuvre
TCS Thermal-Control Sub-system
TCWG Telescope Calibration Working Group
TD Telescope Demonstrator
TDA Technology Demonstrator (Development) Activity
TDA Technology Development Activity
TDB Barycentric Dynamical Time
TDM Time-Domain Multiplexing
TDP Technical Data Package
TDP Technology Development Plan
Te2v Teledyne e2v technologies
TEB Tender Evaluation Board
TEC TEChnical Directorate (of ESA)
TEC-EES space Environments and Effects Section in ESA's TEChnical Directorate
TECNET TEChnology NETwork (ESA)
TED Thermo-Elastic Displacement/Distortion
TES Transition Edge Sensor
TF Thermal Filter (obsolete; use THF instead)
TF Transfer Function
TFA Thin Filter Assembly
TGT Thermal Gradient Test
THESEUS Transient High-Energy Sky and Early-Universe Surveyor
THF Thermal Filter (replaces TF)
Ti Titanium
TiAl6V4 Titanium-Aluminium alloy
TID Total Ionising Dose
TIDL Total Ionising Dose Level
TIDS Total Ionising Dose Sensitivity
TIM Technical Interface Meeting (ESA-NASA)
TLM TeLeMetry
TM Telemetry
TMD Tuned (Tunable) Mass Damper
TML Total Mass Loss
TN Technical Note
TN Technical Nugget (ACO)
TNID Total Non-Ionising Dose
TNIDL Total Non-Ionising Dose Level
TNIDS Total Non-Ionising Dose Sensitivity
TNO Technical NOte
TO Technical Officer
TOC Table of Contents
TOC Total Organic Carbon
ToF Time of Flight
ToO Target of Opportunity
TP Technical Panel
TP Technology Plan
TP Test Port
TP Topical Panel
TP Transfer Phase
TPA Telescope Performance Assessment
TPC Topical Panel Chair
TQCM Temperature-controlled Quartz Crystal Microbalance
TRA Technology Readiness Assessment
TRB Test Review Board
TRD Technical Requirements Document
TRD Telescope Reference Design
TRD Test Requirements Document
TRL Technology Readiness Level
TRoPIC single photon counting CCD camera, eROSITA prototype camera
TRP Technology Research Program
TRP Temperature Reference Point
TRR Test Readiness Review
TRS Technical Requirement Specification
TRSL Technology Readiness Status List
TS Technical Specification
TSTR Transfer Star TRacker
tSZ thermal Sunyaev-Zeldovitch (effect)
TT Terrestrial Time
TT&C Telemetry, Tracking, and Command(ing)
TTC Telemetry and TeleCommand
TTV Total Thickness Variation
TV Thermal Vacuum
TV/TC Thermal Vacuum/Thermal Cycling
TVAC Thermal-VACuum (test / chamber)
TWG Telescope Working Group
TWT Traveling Wave Tube
TWTA Travelling Wave Tube Amplifier
Tx Translation along the x-axis
Ty Translation along the y-axis
Tz Translation along the z-axis
UC Use Case
UFO Ultra-Fast Outflow
UG University of Geneva
UK United Kingdom
UKSA United Kingdom Space Agency
UL University of Leicester
ULPA Ultra-Low-Particle Air (filter)
ULX Ultra-Luminous X-ray (source)
um micrometer
UM User Manual
UniPa University of Palermo
URD User Requirements Document
US United States (of America)
US Upper Section (of FMS)
USD United States Dollar
UTC Universal Coordinated Time
UTC Universal Time Coordinated
uTCA micro Telecommunications Computing Architecture (connector)
UV Ultra-Violet
uVib micro Vibrations
UVOB Ultra-Violet Optical Bench
V Volt
V/I Voltage and/or current
V&V Verification and Validation
VBQC Vacuum Balance Quartz Crystal
VCB Verification Control Board
VCD Verification Control Document
VCDM Verification Control Document and Matrix
VCM Verification Control Matrix
VCM Volatile Condensable Material
VDD Drain-to-Drain Voltage
VEM Viscous-Elastic Material
VERITAS VErsatile Readout based on Integrated Trapezoidal Analogue Shapers
VF Vignetting Function
VF Vignetting Function (Vignetting Factor)
VG ViewGraph
VIS Vibration Isolation Sub-system
VIS VISible (wavelength)
VLM Very Low-Mass (star)
VM Verification Matrix
VO Virtual Observatory
VRR Verification Readiness Review
VSUB Back-gate bias
VTT Valtion Teknillinen Tutkimuskeskus (Finland's State Technical Research Centre)
W Watt
W Window (mode)
W-I Wolter telescope of type I
W-S Wolter-Schwarzschild
W1 Wolter-1 (design)
WA Wolter(-1) Athena
WAN Wide Area Network
WBS Work Breakdown Structure
WCA Worst-Case Analysis
WCPE Worst Case Potential Effect
WD White Dwarf
WDA WFI Data Analysis (software)
WDE Wheel Drive Electronics
WEDM Wire(-cut) Electrostatic Discharge Machining
WFEE Warm Front-End Electronics
WFI Wide-Field Imager
WFOIS Wide-Field Optical/Infrared Surveyors
WFR Weibull Failure Rate
WG Working Group
WGS World Geodetic System
WHIM Warm-Hot Inter-galactic Medium
WISC WFI Instrument Science (and data) Centre (also W-ISC)
WM Windowed Mean
WMS Windowed Mean Stability
WP White Paper
WP Work Package
WPD Work Package Description
WPM Work Package Manager
WPR Weighted Particle Rate
WPS Work Package Structure
WSAS WFI Science Analysis Software
WSB Weak Stability Boundary
WSS Warm Support Structure
WST WFI Science Team
X-COP XMM-Newton Cluster Outskirts Project
X-IFU X-Ray Integrated Field Unit
X-ISC X-IFU Instrument and Science (and data) Centre
XARM X-ray Astronomy Recovery (Replacement) Mission (“Hitomi-2”); obsolete and now called XRISM
XCaT X-IFU Calibration Team
XCM X-IFU Consortium Meeting
XCMT X-IFU Consortium Management Team
XCoB X-IFU Consortium Board
XDA X-IFU Data Analysis (software)
XDIN X-ray Dim Isolated Neutron (star)
XDS X-ray Detector System
XEUS X-ray Evolving-Universe Spectroscopy (obsolete)
XISC X-IFU Instrument Science Centre
XMM X-ray Multi Mirror Mission
XMS X-ray Micro-calorimeter Spectrometer (obsolete)
XOAT X-ray Optical Assembly Tool (stacking robot)
XOU X-ray Optical Unit
XPBF X-ray Pencil-Beam Facility (at PTB)
XRB X-Ray Binary
XRCF X-Ray and Cryogenic Facility (at MSFC; formerly known as X-Ray Calibration Facility)
XRR X-ray Reflectivity (Reflectometry)
XRS X-Ray Scattering
XRS X-Ray Source
XRTG4 X-Ray Tracer based on Geant-4
XSA XMM-Newton Science Archive
XSAT X-IFU Science Advisory Team
XSS X-ray Source System
XTA X-ray Tube Assembly
YSH-70A Ultra-high modulus composite
YSO Young Stellar Object
z redshift
µV micro-Vibration