List of Acronyms and Abbreviations

This list contains definitions for Orbiter or important spaceflight acronyms or abbreviations, especially those appearing in MFDs and various HUD modes.

One entry in this list consists of a term with one or more definitions, like:

Term

Definition

;Term:Definition

Don't use links in the term part of a entry, please do so in the definition part, for keeping a consistent look-and-feel and don't putting to much emphasis on a single definition.

Terms without definitions will get moved to the talk page into the section "Wanted definitions". If you have multiple definitions for a term, the definition part should turn into a numbered list, like:

Term

1. Definition 1
2. Definition 2
3. Definition 3

;Term:
#Definition 1
#Definition 2
#Definition 3

The order of the definitions should be like that:

1. Orbiter HUD definitions
2. Orbiter MFD definitions
3. General Orbiter definitions
4. Orbiter Add-on definitions
5. General spaceflight definitions

If you don't agree to a ordering of definitions, please complain in the talk page about the entry.

See also

• Russian glossary
• List of Acronyms and Abbreviations for the ISS

---

Contents: Top - 0–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

ACC

Acceleration, used in Surface MFD to indicate increasing or decereasing horizontal speed of the ship in m/s²

ACT

Activate, command button in RCS attitude MFD in docking mode to activate the programmed orientation to the target dock

AgP

Argument of periapsis:The angle in the orbit from the point of the ascending node to the point of periapsis, displayed in Orbit MFD

ALT or Alt

altitude, distance from the body surface

1. Used in Orbit MFD when Alt mode is selected to indicate distance from the surface of the body
2. Used in Surface MFD to indicate altitude in km from the body surface

AN

ascending node:a vector in an orbit where the body passes from south to north of the plane of reference (i.e. ecliptic or equatorial). Shown in Align MFD and Orbit MFD as a dotted vector line connecting to a solid square on the orbit.

AOA

Angle of attack, the difference between the ship's direction of travel and the pitch of its nose

1. Used in Surface MFD to indicate the angle of attack

AORP

Autonomous Orbiter Rapid Prototype, a system to allow a shuttle orbiter to land without crew.

AP

Used in Surface MFD, a red rectangle with white "AP" in the altitude tape to indicate the altitude of the ship's apoapsis

ApA

apoapsis apoapsis altitude, the lowest altitude of an orbit, displayed in Orbit MFD.

ApD

apoapsis apoapsis distance

ApR

apoapsis apoapsis radius, displayed in Orbit MFD

ApT

time to apoapsis in seconds, displayed in Orbit MFD

AR

1. Automatic Reference, used in Align MFD, Orbit MFD as a command button for Align to select a reference body automatically based on highest gravity
2. Altitude Range, used to manually set the range in the altitude graph in Ascent profile MFD
3. acceptance review

atmo

atmosphere

ATM DATA

Atmospheric data in Surface MFD readouts

ATV

1. Autonomous Transfer Vehicle, an unmanned cargo spacecraft, see ATV.
2. Automated Transfer Vehicle[1]

AU

astronomical unit

AX

Axis, command button in RCS attitude MFD to change the selected axis beetween pitch/yaw/roll

Back to top

B

BAS

Basemode, command button to select programmed attitude (prograde, orbit normal, perpendicular in, radial down) in RCS attitude MFD

BMW

Bate, Mueller, White - authors of Fundamentals of Astrodynamics (1971)

BRG

Bearing, used in the Horizontal Situation Indicator MFD to indicate the compass direction of the ILS or VOR transmitter

Back to top

C

CaLV

Cargo launch vehicle, see Ares V

CDI

course deviation indicator

CDR

1. commander
2. critical design review

CEV

Crew expedition vehicle, see CEV

CFD

computational fluid dynamics

CFG

command button in RCS attitude MFD to switch to configuration page

CLV

Crew launch vehicle, see Ares I

CNC

Cancel, used in RCS attitude MFD in the docking mode to cancel the docking mode program

COAS

Crew Optical Alignment Sight

COM

communication or communicator

CRS

Course, indicates the ship's course (heading) in the Horizontal Situation Indicator MFD

CTD

crash to desktop

CTRL

Control

CTV

1. Crew Transfer Vehicle, a manned spacecraft derived from the ATV, see CTV
2. Compatibility Test Van, NASA

CUR

Command button in RCS attitude MFD to set the programmed attitude to the current attitude

CVEL

1. closing velocity
2. Common Vessel Extensions Light, see CVEL

Back to top

D

D3D9

refers to the advanced graphics client in Orbiter

Da

Deviation, displayed in RCS attitude MFD to indicate how many degrees the ship has to go in Roll to reach programmed attitude

DCK

command button in RCS attitude MFD to set the MFD into Docking mode

DDT&E

design, development, test and evaluation

DEV

Deviation, in the Horizontal Situation Indicator MFD, it indicates how far the OBS is adjusted left or right of the radial

DG

Delta-glider

DG4

Orbiter's stock DG

DGIII

DeltagliderIII, a famous enhanced version of the Delta-glider.

DGIV

DeltaGliderIV, an improved version of the DeltaGliderIII.

DG-S

Delta-glider equiped with two scramjets.

Dir

direction

Dist

distance

1. Displayed in Sync MFD, distance ship to target

DIV

divergent, i.e. yaw gimbal mode.

DLng

difference in longitude between ship and target, displayed in Sync MFD

DN

1. Down, used in Map MFD when Tracking mode is off and map zoomed in to scroll the map down so you can see farther South
2. Command button in RCS attitude MFD to change the selected modification up so you can edit it
3. descending node

DNP

dynamic pressure, given in Pa

1. Displayed in Surface MFD to indicate atmospheric pressure

DNS

atmospheric density, given in kg m^-3, symbol ρ

1. displayed in Surface MFD

DPS

Data Processing System. Term describing the general purpose computers and their interfaces onboard various manned spacecraft

Dr

Deviation, displayed in RCS attitude MFD to indicate how many degrees until the ship reaches pitch and yaw alignment with the programmed attitude

DSP

Display, used in Map MFD to switch between Ground Track Display and Orbital Plane Display

DST or Dst

1. Distance (to target), used in the Horizontal Situation Indicator MFD to indicate distance to the selected ILS or VOR transmitter
2. Distance, used in Orbit MFD to select between Rad, ApR, PeR (distance from body center) and Alt, ApA, PeA (distance from body surface)

DTe

time to ejection, as seen on the transfer MFD

DTi

time to intercept, as seen on the transfer MFD

DTmin

time of arrival difference

1. Displayed in Sync MFD to indicate difference in time between ship and target passing the intersection point

Dv

delta velocity, as seen on the transfer MFD, see also Delta-V

Back to top

E

Ecc

eccentricity of orbit, displayed in Orbit MFD

ECL

plane of the ecliptic

ECLSS

Environmental control and life support system

ECSS

european cooperation for space standardization

EELV

Evolved Expendable Launch Vehicle

ELS

ELements, custom Select, used in Align MFD to select a custom orbital elements to which to align

END

command button in RCS attitude MFD to stop the programmed attitude mode

EQU

plane of the equator

EQU POS

Equatorial position, given as longitude and latitude

1. Displayed in Surface MFD given as position and rate of change

ESA

European Space Agency

ESAS

Exploration Systems Architecture Study

ET

external tank

EVA

Extra vehicular activity, see EVA

Back to top

F

FGB

Russian abbreviation for Functional Cargo Block. See FGB

FoV

field of view, as seen in the general information display

FPS

frame rate (frames per second), as seen in the general information display

FRF

Flight Readiness Firing, a launch countdown test of the Shuttle running all except SRB ignition and lift-off.

FRM

Frame of reference, used in Orbit MFD to change the orbital display and parameters between Equatorial or Ecliptic

Back to top

G

G or g

1. used in Orbit MFD, indicates what fraction of gravity is exerted on the ship by the reference body (0 to 1)
2. unit of acceleration. 1g equals the gravity acceleration on earths surface, 9.81 m/s²

GET

Ground Elapsed Time [2]

GL

Used often as vehicle name prefix for a Delta-glider

GLOC

Gravity-induced Loss of Consciousness

GMT

Greenwich Mean Time.See Universal Time on Wikipedia

GO

Go, command button in RCS attitude MFD, once the desired orientation and modifications are set, to activate the program

GPDS

Generic Payload Description System

GPS

Global Positioning System

GS

Ground speed

1. Command button in Surface MFD to set the speed tape to GS

GTO

geostationary transfer orbit

Back to top

H

H

Horizon

HAC

Heading Alignment Cone

HLLV

heavy lift launch vehicle

HSI

horizontal situation indicator

HST

Hubble Space Telescope

HTO

hypothetical transfer orbit, as seen on the transfer MFD

HUD

heads up display, used in Docking MFD, Orbit MFD, Surface MFD to copy the current parameters to the HUD

Back to top

I

IAS

indicated air speed Indicated airspeed

1. Command button in Surface MFD to set the speed tape to IAS

IDS

instrument docking system, used in Docking MFD

ILS

1. instrument landing system
2. also used in Horizontal Situation Indicator MFD to indicate which runway at which Spaceport is selected by the NAV system
3. International launch services, a US-russian joint venture marketing Atlas and Proton launches

Inc

Inclination, angular difference between one orbit with respect to another, usually the ecliptic, equatorial, body orbit, or target orbit, displayed in Align MFD, Orbit MFD

INV

Inverse, command button in RCS attitude MFD to change the programmed attitude to the inverse (retrograde, orbit antinormal, perpendicular out, radial up)

ISP

specific impulse

ISS

International Space Station

Back to top

J

JD

Julian date

JSC

Lyndon B. Johnson Space Center

JWST

James Webb Space Telescope

Back to top

K

KISS

"Keep it simple, stupid!" Famous engineering dogma.[3]

KSC

Kennedy Space Center

Back to top

L

LAN

1. Longitude of the ascending node, used in Align MFD, Orbit MFD
2. local-area network

LCC

1. launch control center
2. life cycle cost

LDEF

Long Duration Exposure Facility

LEN

List Length

1. Command button in Sync MFD to select number of orbits to display (lines 0-18)

LEO

Low earth orbit

LH2

Liquid Hydrogen

LOCV

Loss of crew and vehicle

LOX

Liquid Oxygen

LPe

longitude of periapsis, displayed in Orbit MFD

L/R

Left/Right, used in Horizontal Situation Indicator MFD to switch MFD mode focus to the left or right graphic display

Back to top

M

m

metre

M

1. Mega (SI prefix for 10⁶).
2. Mass, given in kg
3. mach number or multiples of speed of sound in a given medium
   1. Used in Surface MFD ship's speed is given in mach number as well as m/s

MCC

1. mid course correction
2. mission control center

MCC-H

mission control center Houston

MCC-M

mission control center Moscow

MDR

mission definition review

MECO

main engine cutoff

MET

Mission Elapsed Time. See Mission Elapsed Time on Wikipedia.

MFD

Multifunctional Display, see MFD

MHz

MegaHerz, same as the old term megacycles/second, radio and transponder frequency, used in COMNAV MFD

MJD

modified Julian date

MLP

Mobile Launcher Platform

MMOD

Micrometeorites and orbital debris

MMU

manned maneuvering unit, see MMU

MnA

mean anomaly, displayed in Orbit MFD

MnL

mean longitude, displayed in Orbit MFD

MOD

used in Orbit MFD and Sync MFD to cycle the display between parameters only, orbital display only, or both

m/s

meters per second, the SI base unit of velocity

MSx

Mission Specialist x

Back to top

N

NAV

1. Navigatonal receiver,
   1. in COMNAV MFD it is used to identify up to four receivers in the stack
   2. in Horizontal Situation Indicator MFD, it is used to select which receiver an HSI display is tuned to
   3. in RCS attitude MFD command button in Docking mode to slave one of the Nav receivers to this MFD
2. navigation
3. navigation aid

NT

No target, used in Orbit MFD to deselect the target

Back to top

O

OAT

outside air temperature, displayed in Surface MFD given in Kelvins (K)

Ob

1. Obliquity of ecliptic (tilt of axis of rotation against plane of ecliptic)
2. Orbit, displayed in Sync MFD indicates how many orbits remaining until rendezvous

OB+ and OB-

OmniBearing, used to change the offset of the course arrow to left or right of the beam

OBS

omni bearing selector

OBT

orbit, as seen on the orbit MFD

OMBUU

Orbiter Midbody Umbilical Unit

OMP

Orbiter Multiplayer Project, an ongoing program to create a multiplayer server in Orbiter.

OMS

Orbital Maneuvering System, the 'main engines' of the space shuttle orbiter

OS

Orbital speed

1. Command button in Surface MFD to set the speed tape to OS

Back to top

P

P

position (sometimes radius) vector, as seen on the align orbital plane MFD

p0

atmospheric pressure at sea level

PAM

Payload Assist Module, a family of solid upper stages for the Space Shuttle

PAPI

Precision Approach Path Indicators, lit runway centerline.

PB

Shuttle PB

PDR

preliminary design review

PDRS

Payload Deployment and Retrieval System, the official name of the robot arm of the Space Shuttle

PeA

periapsis altitude. Altitude of periapsis above the surface of the orbited body, used in Orbit MFD

PeD

periapsis distance. See PeR.

PeR

periapsis radius. Distance of periapsis from the center of the orbited body, used in Orbit MFD

PeT

time to periapsis in seconds, displayed in Orbit MFD

PG

1. Page, switching displayed pages in an MFD mode, used in Align MFD and Ascent profile MFD
2. prograde

PLT

Pilot

PMI

Principal moments of inertia, see PMI

Pos

position

PRJ

Projection, used in the Orbit MFD to switch orbital display between Ecliptic, Equatorial, Ship's orbit, Target orbit

PRR

preliminary requirements review

PSx

Payload Specialist x

Back to top

Q

QR

qualification review

Back to top

R

R

1. mean radius
2. specific gas constant

+R and -R

1. Command buttons in RCS attitude MFD (R+) to add a line (pitch, yaw, roll) to the programmed attitude, or R- to remove the last line
2. Command buttons in Sync MFD to rotate intersection points

r0

atmospheric density at sea level

Rad

1. Displayed in Orbit MFD when Radius mode is selected to indicate distance from the center of the body in meters
2. radial distance
3. angular unit radians

RAnm

true anomaly of reference axis, displayed in synchronise orbit MFD

Rate

How fast the current orbital plane is changing, degrees per second, used in Align MFD

RCS

reaction control system, spacebourne orientation rocket system.

R&D

research and development

RDT&E

research, development, testing and evaluation

REF

Reference

1. used in Align MFD, Map MFD, Orbit MFD to select a reference body.
2. Ref: Reference displayed in Sync MFD to switch Reference axis

RG

retrograde

RInc

relative inclination, relative inclination between the ship and target orbits, used in Align MFD and Sync MFD

RKA

Russian Space Agency

RMS

Remote Manipulator System

RS

Russian-side, used as prefix for orientation when describing ISS components.

RSLS

Redundant set launch sequencer, the computer systems responsible for the ignition of the SSMEs in the Space Shuttle orbiter.

RTFM

Read the fine (or many other f-words) manual, a typical forum answer for questions already answered extensivly in the manual.

RTLS

Return to launch site, a Space Shuttle abort mode.

RTN

Return, command button in RCS attitude MFD to return the display to the Active mode page

RVel

relative velocity

1. Displayed in Sync MFD, Relative speed between ship and target

Back to top

S

SAR

1. Search and rescue.
2. Syntetic aperture radar, a radar mode used for creating navigation maps or detect slowly moving ground vehicles.

S/C

spacecraft

SC< and SC>

SCan frequency up or down in the currently selected receiver, used in COMNAV MFD

SDK

Software Development Kit [4]

SDHLV

Shuttle Derived Heavy Launch Vehicle, see Ares V

SDLV

Shuttle Derived Launch Vehicle, see Ares

SECO

1. Secondary Engine Cutoff
2. Sustainer Engine Cutoff

SET

Set, used in RCS attitude MFD to set the desired attitude

SHP

Ship, used in Map MFD to indicate your ship's name, position, altitude, course of your ship

Sim

1. simulation time (in seconds), as seen in the general information display
2. a common abbreviation for "simulator"

Sh-ToR

ship time-on-reference, as seen on the synchronise orbit MFD

SI unit

The metric system of measurement, the modern name, see SI unit

SL+ and SL-

Select, change which receiver to next or previous receiver to adjust frequency, used in COMNAV MFD

SLF

shuttle landing facility, see Cape Canaveral

SMa

semi-major axis, used in Orbit MFD

SMi

semi-minor axis, used in Orbit MFD

SRB

Solid Rocket Booster [5]

SRTM

Shuttle radar topography mission, see SRTM.

SSME

Space Shuttle Main Engines [6]

SSTO

Single Stage to Orbit

STOVL

Short take-off, vertical landing. As performed by the DG on full fuel employing hover thrusters during takeoff.

STP

static pressure, given in Pa

1. Displayed in Surface MFD to indicate atmospheric pressure

STS

space transportation system, AKA space shuttle, see space transportation system

SUS

command button in RCS attitude MFD to suspend programmed attitude temporarily

Back to top

T

T

orbit period, measured in seconds, displayed in Orbit MFD

TAEM

Terminal Area Energy Management

TAS

true air speed True airspeed

1. Command button in Surface MFD to set the speed tape to TAS

TEI

Trans Earth Injection[7]

TGT

TarGeT

1. command button used in Align MFD, Docking MFD, Map MFD, Orbit MFD, and Sync MFD to select a target
2. used in the Map MFD display to indicate target name, position, altitude of the target

Tg-ToR

target time-on-reference, as seen on the synchronise orbit MFD

TKS

russian spacecraft for the Almaz program, see TKS

TLA

Three letter acronym for a three letter acronym.

TLE

two-line elements

TLe

eject longitude, as seen on the transfer MFD

TLi

intercept longitude, as seen on the transfer MFD

TLI

Trans Lunar Injection

Tn

Time to node, used in Align MFD

TOFS

tangential offset docking MFD

ToR

time on reference axis, displayed in Sync MFD to indicate number of seconds until ship or target passes the intersection point

TrA

true anomaly, displayed in Orbit MFD

TRK

Track, used in map MFD to keep the ship centered in the map display

TrL

true longitude, displayed in Orbit MFD

TRL

technology readiness level

Ts

length of siderial day

TthA

Estimated thrust time at the ascending node to align planes, used in Align MFD

TthD

Estimated thrust time at the descending node to align planes, used in Align MFD

TVEL

tangential velocity

Back to top

U

UMMU

Universal manned maneuvering unit, popular add-on, see Universal MMU.

UNKS

unknown problems, you are aware of.

UNK-UNKS

unknown problems, you are not aware of.

UP

1. UP, used in Map MFD when Track mode is off and map is zoomed in to scroll the map up to see farther North
2. Command button in RCS attitude MFD to change the selected modification up so you can edit it

UT

universal time, GMT. Not to be confused with UTC (Universial Time Co-ordinated). The latter is based on atomic clocks not astronomy, hence the occasional leap-second to correct UTC to GMT.

Back to top

V

+V and -V

Used in RCS attitude MFD to add or subtract one degree each click the programmed attitude mode

VACC

Vertical acceleration, used in Surface MFD how fast rate of ascent or descent is increasing or decreasing in m/s²

VASI

Visual Approach Slope Indicator, the glideslope lighting system ajacent to runways to guide pilots onto the correct angle of glideslope (normally 3 degrees).

VC

1. virtual cockpit
2. Visual C++, an IDE and C++ compiler by Microsoft.

Vel

velocity, displayed in Orbit MFD

VOR

1. very high frequency omnidirectional radio
2. used in the Horizontal Situation Indicator MFD to indicate which VOR transmitter is selected by a NAV radio, if it's selected to a VOR transmitter

VRR

Velocity Radial Range, used to manually set the range in the Radial Velocity graph in Ascent profile MFD

VS

vertical speed

1. Used in Surface MFD to indicate rate of ascent or descent in meters per second

VSA

Virtual Space Agency

VSI

Vertical Speed Indicator, used in Surface MFD, the VS tape reading rate of ascent or descent, in m/s

VTOL

Vertical Take Off and Landing

VTR

Velocity Tangential Range, used to manually set the range in the Tangential Velocity Range graph in Ascent profile MFD

Back to top

W

WBS

work breakdown structure

WPD

work package description

Wrp

time acceleration factor, seen in the general information display

X

XPDR

transponder, used in Docking MFD

Y

YSC

Yokohama Science Center

Z

ZM+ and ZM-

zoom,used in Map MFD to zoom the map display in and out

Back to top

Contents: Top - 0–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z