Calculation Parameters

General Mission Analysis Tool

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Calculation Parameters

Calculation Parameters — Resource properties available for use by commands and output

Description

Parameters are named resource properties that can be used to obtain data for use by Mission Sequence commands or by output resources. Some parameters, such as the Altitude parameter of Spacecraft, are calculated values that can only be used to retrieve data. They cannot be set directly. Others, such as the Element1 parameter of ImpulsiveBurn, share the same name as a resource field and can be used both to set data and retrieve it. Parameters are distinguished from resource fields by their extra functionality: fields are static resource properties that are usually set in initialization (or in the GUI Resources tree), while parameters can be calculated on the fly and used in plots, reports, and mathematical expressions.

Parameters are classified as one of four types: central-body-dependent parameters, coordinate-system-dependent parameters, attached-hardware parameters, and standalone parameters. Standalone parameters are the simplest type, as they have no dependencies. The ElapsedSecs parameter of Spacecraft is an example of this; it is simply referenced as Spacecraft.ElapsedSecs.

Central-body-dependent parameters, as the name suggests, have a value that is dependent on the chosen celestial body. The Altitude parameter of Spacecraft is an example of this. To reference this parameter, you must specify a central body, such as Spacecraft.Mars.Altitude. Any built-in central body or user-defined Asteroid, Comet, Moon, or Planet is valid as a dependency.

Likewise, coordinate-system-dependent parameters have a value that is dependent on the chosen coordinate system. The DEC parameter of Spacecraft is an example of this. To reference this parameter, you must specify the name of a CoordinateSystem resource, such as Spacecraft.EarthFixed.DEC. Any default or user-defined CoordinateSystem resource is valid as a dependency.

If a dependency is used when retrieving the value of the parameter, as in the following line, the value of Altitude is calculated at Mars before setting it to the variable x. If the dependency is omitted, Earth and EarthMJ2000Eq are assumed unless noted otherwise.

x = DefaultSC.Mars.Altitude

If a dependency is used when setting the value of a parameter, the value of the parameter is first converted based on the value of the dependency, then the value is set. For example, in the following line, the value of SMA is first calculated at Mars, then it is set to the value 10000 in that context. If the dependency is omitted when setting the value, the default is assumed to be the central body or coordinate system of the parent resource (in this case, DefaultSC).

DefaultSC.Mars.SMA = 10000

Attached-hardware parameters have no dependencies, but are themselves dependent on being attached to a Spacecraft. ChemicalTank and ChemicalThruster parameters are examples of this. The FuelMass parameter of ChemicalTank cannot be referenced without first attaching the ChemicalTank to a Spacecraft. Then, the parameter can be referenced as: Spacecraft.FuelTank.FuelMass.

The individual parameters are resource-specific, and are documented in the tables below. The GUI has a parameter selection interface that is common to all parameters. This interface is documented in GUI, below.

See Also: Array, ChemicalTank, ImpulsiveBurn, FiniteBurn, Spacecraft, String, ChemicalThruster, Variable

GUI

Parameters can be used as input in several places throughout GMAT, such as the ReportFile and XYPlot resources and the If/Else, Propagate, and Report commands. In the GUI, all of these use a common interface called the ParameterSelectDialog that allows for interactive parameter selection. A basic ParameterSelectDialog window looks like the following:

The ParameterSelectDialog window is used to build a parameter, along with any dependencies, for use in a command or resource. Some resources and commands have different requirements for the types of parameters that can be used, so the ParameterSelectDialog can take slightly different forms, depending on where it's used. This section will describe the generic interface, then mention any resource- or command-specific exceptions.

General Usage

The first step in choosing a parameter is to select the object (or resource) type from the Object Type list in the upper left. Seven types can appear in this list: Spacecraft, SpacePoint, ImpulsiveBurn, FiniteBurn, Variable, Array, and String.

Once you've selected a type, The Object List box is populated with all existing resources of that type. Use this list to choose the specific resource you'd like to reference.

If the Spacecraft type is selected, the Attached Hardware List appears below the Object List. This list displays any hardware (such as ChemicalTank or ChemicalThruster resources) attached to the selected Spacecraft. If the Array type is selected, Row and Col boxes appear. Use these to specify a row and column to select an individual array element, or check Select Entire Object to choose the entire array.

Once a resource is selected, the Object Properties list is populated with all available parameters provided by that resource. Some resources, such as instances of Variable or Array, are themselves parameters, so this list remains empty.

Parameters with different dependency types are commingled in the Object Properties list. When you select one, the appropriate dependency (if any) appears below the list. For example, after selecting the Spacecraft AOP parameter, a CoordinateSystem list appears. After selecting the Spacecraft Apoapsis parameter, a Central Body list appears. And after selecting the Spacecraft Cd parameter, no dependency list appears. To select a range of parameters from the Object Properties list, hold down the Shift key while selecting the second endpoint of the range. To select multiple individual parameters, hold down the Ctrl key while making each selection.

To select a parameter, select the appropriate Object Type, the specific resource from the Object List or Attached Hardware List, the desired parameter from the Object Properties list, and the required dependency, and add it to the Selected Value(s) list on the right. There are six buttons available to control this list:

  • UP: Move the selected item in the Selected Value(s) list up one position (if allowed).

  • DN: Move the selected item in the Selected Value(s) list down one position (if allowed).

  • ->: Add the selected item in the Object Properties list to the Selected Value(s) list.

  • <-: Remove the selected item in the Selected Value(s) list.

  • =>: Add all items to the Selected Value(s) list.

  • <=: Remove all items from the Selected Value(s) list.

When finished, the Selected Value(s) list contains the final selected parameters. Click OK to accept the selection.

The ordering of the Selected Value(s) list is significant in certain circumstances (such as in the Add field of ReportFile), but not in others. See the documentation for each resource or command for details.

Special Considerations

Some resources and commands (such as the Propagate command Parameter argument) only accept a single parameter as input; in this context the ParameterSelectDialog only allows one parameter in the Selected Value(s) list and does not allow use of the UP, DN, and => buttons.

In some instances (such as in the Vary command), only parameters that are also fields (and so can be set in the Mission Sequence) can be used. In this case only the allowed parameters will be shown in the Object Properties list.

In the Propagate command Parameter argument, only parameters of Spacecraft can be used. In this case only Spacecraft will be shown in the Object Type list.

Parameters

Spacecraft

Parameter Settable Plottable Description
A1Gregorian Y N

Spacecraft epoch in the A.1 system and the Gregorian format.

Data Type

String

Dependency

(None)

Units

(N/A)
A1ModJulian Y Y

Spacecraft epoch in the A.1 system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
Acceleration N Y

The total acceleration with respect to the inertial system computed using the ForceModel selected for the dependency.

Data Type

Real

Dependency

ForceModel

Units

km/s^2
AccelerationX N Y

The x-component of acceleration with respect to the inertial system computed using the ForceModel selected for the dependency.

Data Type

Real

Dependency

ForceModel

Units

km/s^2
AccelerationY N Y

The y-component of acceleration with respect to the inertial system computed using the ForceModel selected for the dependency.

Data Type

Real

Dependency

ForceModel

Units

km/s^2
AccelerationZ N Y

The z-component of acceleration with respect to the inertial system computed using the ForceModel selected for the dependency.

Data Type

String

Dependency

ForceModel

Units

km/s^2
AltEquinoctialP Y Y

See Spacecraft.AltEquinoctialP

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
AltEquinoctialQ Y Y

See Spacecraft.AltEquinoctialQ

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
Altitude N Y

Distance to the plane tangent to the surface of the specified celestial body at the sub-satellite point. GMAT assumes the body is an ellipsoid.

Data Type

Real

Dependency

CelestialBody

Units

km
AngularVelocityX Y Y

See Spacecraft.AngularVelocityX

Data Type

Real

Dependency

(None)

Units

deg/s
AngularVelocityY Y Y

See Spacecraft.AngularVelocityY

Data Type

Real

Dependency

(None)

Units

deg/s
AngularVelocityZ Y Y

See Spacecraft.AngularVelocityZ

Data Type

Real

Dependency

(None)

Units

deg/s
AOP Y Y

See Spacecraft.AOP

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ AOP < 360°

Units

deg
Apoapsis N Y

A parameter that equals zero when the spacecraft is at orbit apoapsis. This parameter can only be used as a stopping condition in the Propagate command.

Data Type

Real

Dependency

CelestialBody

Units

(None)
AtmosDensity N Y

The atmospheric density at the current Spacecraft epoch and location computed using the ForceModel selected for the dependency.

Data Type

String

Dependency

ForceModel

Units

kg/km^3
AZI Y Y

See Spacecraft.AZI

Data Type

Real

Dependency

CoordinateSystem

Output Range

-180° ≤ AZI ≤ 180°

Units

deg
BdotR N Y

B-plane B·R magnitude.

GMAT computes the B-plane coordinates in the coordinate system specified in the dependency. In many implementations, the B-plane coordinates are computed in a pseudo-rotating coordinate system where the ω×r term is not applied when transforming velocity vectors. GMAT does apply the ω×r term in the velocity transformation. When computing B-plane coordinates in inertial systems, this term is identically zero. For rotating systems such as the Sun-Earth body-body rotating system, the effect of including ω×r is small but noticeable when comparing results between systems. When the rotation of the selected coordinate system is "fast", the values may differ significantly.

Data Type

Real

Dependency

CoordinateSystem

Units

km
BdotT N Y

B-plane B·T magnitude. See the BdotR parameter for notes on this calculation.

Data Type

Real

Dependency

CoordinateSystem

Units

km
BetaAngle N Y

Beta angle (or phase angle) between the orbit normal vector and the vector from the celestial body to the sun.

Data Type

Real

Dependency

CelestialBody

Output Range

-90° ≤ BetaAngle ≤ 90°

Units

deg
BrouwerLongAOP Y Y

See Spacecraft.BrouwerLongAOP.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ BrouwerLongAOP ≤ 360°

Units

deg
BrouwerLongECC Y Y

See Spacecraft.BrouwerLongECC.

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
BrouwerLongINC Y Y

See Spacecraft.BrouwerLongINC.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ BrouwerLongINC ≤ 180°

Units

deg
BrouwerLongMA Y Y

See Spacecraft.BrouwerLongMA.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ BrouwerLongMA ≤ 360°

Units

deg
BrouwerLongRAAN Y Y

See Spacecraft.BrouwerLongRAAN.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ BrouwerLongRAAN ≤ 360°

Units

deg
BrouwerLongSMA Y Y

See Spacecraft.BrouwerLongSMA.

Data Type

Real

Dependency

CoordinateSystem

Units

km
BrouwerShortAOP Y Y

See Spacecraft.BrouwerShortAOP.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ BrouwerShortAOP ≤ 360°

Units

deg
BrouwerShortECC Y Y

See Spacecraft.BrouwerShortECC.

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
BrouwerShortINC Y Y

See Spacecraft.BrouwerShortINC.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ BrouwerShortINC ≤ 180°

Units

deg
BrouwerShortMA Y Y

See Spacecraft.BrouwerShortMA.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ BrouwerShortMA ≤ 360°

Units

deg
BrouwerShortRAAN Y Y

See Spacecraft.BrouwerShortRAAN.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ BrouwerShortRAAN ≤ 360°

Units

deg
BrouwerShortSMA Y Y

See Spacecraft.BrouwerShortSMA.

Data Type

Real

Dependency

CoordinateSystem

Units

km
BVectorAngle N Y

B-plane angle between the B vector and the T unit vector. See the BdotR parameter for notes on this calculation.

Data Type

Real

Dependency

CoordinateSystem

Output Range

-180° ≤ BVectorAngle ≤ 180°

Units

deg
BVectorMag N Y

B-plane B vector magnitude. See the BdotR parameter for notes on this calculation.

Data Type

Real

Dependency

CoordinateSystem

Units

km
C3Energy N Y

C3 (characteristic) energy.

Data Type

Real

Dependency

CelestialBody

Units

MJ/kg (km2/s2)
Cd Y Y

See Spacecraft.Cd

Data Type

Real

Dependency

(None)

Units

(None)
Cr Y Y

See Spacecraft.Cr

Data Type

Real

Dependency

(None)

Units

(None)
CurrA1MJD Y Y

Deprecated. Spacecraft epoch in the A.1 system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
DCM11 Y Y

See Spacecraft.DCM11

Data Type

Real

Dependency

(None)

Units

(None)
DCM12 Y Y

See Spacecraft.DCM12

Data Type

Real

Dependency

(None)

Units

(None)
DCM13 Y Y

See Spacecraft.DCM13

Data Type

Real

Dependency

(None)

Units

(None)
DCM21 Y Y

See Spacecraft.DCM21

Data Type

Real

Dependency

(None)

Units

(None)
DCM22 Y Y

See Spacecraft.DCM22

Data Type

Real

Dependency

(None)

Units

(None)
DCM23 Y Y

See Spacecraft.DCM23

Data Type

Real

Dependency

(None)

Units

(None)
DCM31 Y Y

See Spacecraft.DCM31

Data Type

Real

Dependency

(None)

Units

(None)
DCM32 Y Y

See Spacecraft.DCM32

Data Type

Real

Dependency

(None)

Units

(None)
DCM33 Y Y

See Spacecraft.DCM33

Data Type

Real

Dependency

(None)

Units

(None)
DEC Y Y

See Spacecraft.DEC

Data Type

Real

Dependency

CoordinateSystem

Output Range

-90° ≤ DEC ≤ 90°

Units

deg
DECV Y Y

See Spacecraft.DECV

Data Type

Real

Dependency

CoordinateSystem

Output Range

-90° ≤ DECV ≤ 90°

Units

deg
Delaunayg Y Y

See Spacecraft.Delaunayg.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ Delaunayg < 360°

Units

deg
DelaunayG Y Y

See Spacecraft.DelaunayG.

Data Type

Real

Dependency

CoordinateSystem

Units

km2/s
Delaunayh Y Y

See Spacecraft.Delaunayh.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ Delaunayh < 360°

Units

deg
DelaunayH Y Y

See Spacecraft.DelaunayH.

Data Type

Real

Dependency

CoordinateSystem

Units

km2/s
Delaunayl Y Y

See Spacecraft.Delaunayl.

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ Delaunayl < 360°

Units

deg
DelaunayL Y Y

See Spacecraft.DelaunayL.

Data Type

Real

Dependency

CoordinateSystem

Units

km2/s
DLA N Y

Declination of the outgoing hyperbolic asymptote.

Data Type

Real

Dependency

CoordinateSystem

Output Range

-90° ≤ DLA ≤ 90°

Units

deg
DragArea Y Y

See Spacecraft.DragArea

Data Type

Real

Dependency

(None)

Units

m2
DryMass Y Y

See Spacecraft.DryMass

Data Type

Real

Dependency

(None)

Units

kg
EA N Y

Eccentric anomaly.

Data Type

Real

Dependency

CelestialBody

Output Range

0° ≤ EA < 360°

Units

deg
ECC Y Y

See Spacecraft.ECC

Data Type

Real

Dependency

CelestialBody

Output Range

Units

(None)
ElapsedDays N Y

See Spacecraft.ElapsedDays

Data Type

Real

Dependency

(None)

Units

d
ElapsedSecs N Y

See Spacecraft.ElapsedSecs

Data Type

Real

Dependency

(None)

Units

s
Energy N Y

Specific orbital energy.

Data Type

Real

Dependency

CelestialBody

Units

MJ/kg (km2/s2)
EquinoctialH Y Y

See Spacecraft.EquinoctialH

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
EquinoctialK Y Y

See Spacecraft.EquinoctialK

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
EquinoctialP Y Y

See Spacecraft.EquinoctialP

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
EquinoctialQ Y Y

See Spacecraft.EquinoctialQ

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
EulerAngle1 Y Y

See Spacecraft.EulerAngle1

Data Type

Real

Dependency

(None)

Output Range

0° ≤ EulerAngle1 < 360°

Units

deg
EulerAngle2 Y Y

See Spacecraft.EulerAngle2

Data Type

Real

Dependency

(None)

Output Range

0° ≤ EulerAngle2 < 360°

Units

deg
EulerAngle3 Y Y

See Spacecraft.EulerAngle3

Data Type

Real

Dependency

(None)

Output Range

0° ≤ EulerAngle3 < 360°

Units

deg
EulerAngleRate1 Y Y

See Spacecraft.EulerAngleRate1

Data Type

Real

Dependency

(None)

Units

deg/s
EulerAngleRate2 Y Y

See Spacecraft.EulerAngleRate2

Data Type

Real

Dependency

(None)

Units

deg/s
EulerAngleRate3 Y Y

See Spacecraft.EulerAngleRate3

Data Type

Real

Dependency

(None)

Units

deg/s
FPA Y Y

See Spacecraft.FPA

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ FPA ≤ 180°

Units

deg
HA N Y

Hyperbolic anomaly.

Data Type

Real

Dependency

CelestialBody

Output Range

-∞ < HA < ∞

Units

deg
HMAG N Y

Magnitude of the angular momentum vector.

Data Type

Real

Dependency

CelestialBody

Units

km2/s
HX N Y

X component of the angular momentum vector.

Data Type

Real

Dependency

CoordinateSystem

Units

km2/s
HY N Y

Y component of the angular momentum vector.

Data Type

Real

Dependency

CoordinateSystem

Units

km2/s
HZ N Y

Z component of the angular momentum vector.

Data Type

Real

Dependency

CoordinateSystem

Units

km2/s
INC Y Y

See Spacecraft.INC

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ INC ≤ 180°

Units

deg
IncomingBVAZI Y Y

See Spacecraft.IncomingBVAZI

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ IncomingBVAZI < 360°

Units

deg
IncomingC3Energy Y Y

See Spacecraft.IncomingC3Energy.

Data Type

Real

Dependency

CelestialBody

Units

MJ/kg (km2/s2)
IncomingDHA Y Y

See Spacecraft.IncomingDHA

Data Type

Real

Dependency

CoordinateSystem

Output Range

-90° ≤ IncomingDHA ≤ 90°

Units

deg
IncomingRadPer Y Y

See Spacecraft.IncomingRadPer

Data Type

Real

Dependency

CelestialBody

Units

km
IncomingRHA Y Y

See Spacecraft.IncomingRHA

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ IncomingRHA < 360°

Units

deg
Latitude N Y

Planetodetic latitude.

Data Type

Real

Dependency

CelestialBody

Output Range

-90° ≤ Latitude ≤ 90°

Units

deg
Longitude N Y

Planetodetic longitude.

Data Type

Real

Dependency

CelestialBody

Output Range

-180° ≤ Longitude ≤ 180°

Units

deg
LST N Y

Local sidereal time of the spacecraft from the celestial body's inertial x-axis.

Data Type

Real

Dependency

CelestialBody

Output Range

0° ≤ LST < 360°

Units

deg
MA N Y

Mean anomaly.

Data Type

Real

Dependency

CelestialBody

Output Range

0° ≤ MA < 360°

Units

deg
MHA N Y

Angle between celestial body's body-fixed and inertial axes. For Earth, this is the Greenwich Hour Angle.

Data Type

Real

Dependency

CelestialBody

Output Range

0° ≤ MHA < 360°

Units

deg
MLONG Y Y

See Spacecraft.MLONG

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ MLONG < 360°

Units

deg
MM N Y

Mean motion.

Data Type

Real

Dependency

CelestialBody

Output Range

Units

rad/s
ModEquinoctialF Y Y

See Spacecraft.ModEquinoctialF

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
ModEquinoctialG Y Y

See Spacecraft.ModEquinoctialG

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
ModEquinoctialH Y Y

See Spacecraft.ModEquinoctialH

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
ModEquinoctialK Y Y

See Spacecraft.ModEquinoctialK

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
MRP1 Y Y

See Spacecraft.MRP1

Data Type

Real

Dependency

(None)

Units

(None)
MRP2 Y Y

See Spacecraft.MRP2

Data Type

Real

Dependency

(None)

Units

(None)
MRP3 Y Y

See Spacecraft.MRP3

Data Type

Real

Dependency

(None)

Units

(None)
OrbitPeriod N Y

Osculating orbit period.

Data Type

Real

Dependency

CelestialBody

Units

s
OrbitSTM N N

State transition matrix with respect to the origin-independent MJ2000Eq axes.

Data Type

Array (6×6)

Dependency

(None)

Units

(None)
OrbitSTMA N N

Upper-left quadrant of the state transition matrix, with respect to the origin-independent MJ2000Eq axes.

Data Type

Array (3×3)

Dependency

(None)

Units

(None)
OrbitSTMB N N

Upper-right quadrant of the state transition matrix, with respect to the origin-independent MJ2000Eq axes.

Data Type

Array (3×3)

Dependency

(None)

Units

(None)
OrbitSTMC N N

Lower-left quadrant of the state transition matrix, with respect to the origin-independent MJ2000Eq axes.

Data Type

Array (3×3)

Dependency

(None)

Units

(None)
OrbitSTMD N N

Lower-right quadrant of the state transition matrix, with respect to the origin-independent MJ2000Eq axes.

Data Type

Array (3×3)

Dependency

(None)

Units

(None)
OutgoingBVAZI Y Y

See Spacecraft.OutgoingBVAZI

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ OutgoingBVAZI < 360°

Units

deg
OutgoingC3Energy Y Y

See Spacecraft.OutgoingC3Energy.

Data Type

Real

Dependency

CelestialBody

Units

MJ/kg (km2/s2)
OutgoingDHA Y Y

See Spacecraft.OutgoingDHA

Data Type

Real

Dependency

CoordinateSystem

Output Range

-90° ≤ OutgoingRHA ≤ 90°

Units

deg
OutgoingRadPer Y Y

See Spacecraft.OutgoingRadPer

Data Type

Real

Dependency

CelestialBody

Units

km
OutgoingRHA Y Y

See Spacecraft.OutgoingRHA

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ OutgoingRHA < 360°

Units

deg
Periapsis N Y

A parameter that equals zero when the spacecraft is at orbit periapsis. This parameter can only be used as a stopping condition in the Propagate command.

Data Type

Real

Dependency

CelestialBody

Units

(None)
PlanetodeticAZI Y Y

See Spacecraft.PlanetodeticAZI. This parameter must be used with a CoordinateSystem with BodyFixed axes.

Data Type

Real

Dependency

CoordinateSystem (with BodyFixed axes)

Output Range

-180° ≤ PlanetodeticAZI ≤ 180°

Units

deg
PlanetodeticHFPA Y Y

See Spacecraft.PlanetodeticHFPA. This parameter must be used with a CoordinateSystem with BodyFixed axes.

Data Type

Real

Dependency

CoordinateSystem (with BodyFixed axes)

Output Range

-90° ≤ PlanetodeticHFPA ≤ 90°

Units

deg
PlanetodeticLAT Y Y

See Spacecraft.PlanetodeticLAT. This parameter must be used with a CoordinateSystem with BodyFixed axes.

Data Type

Real

Dependency

CoordinateSystem (with BodyFixed axes)

Output Range

-180° ≤ PlanetodeticLAT ≤ 180°

Units

deg
PlanetodeticLON Y Y

See Spacecraft.PlanetodeticLON. This parameter must be used with a CoordinateSystem with BodyFixed axes.

Data Type

Real

Dependency

CoordinateSystem (with BodyFixed axes)

Output Range

-180° ≤ PlanetodeticLON ≤ 180°

Units

deg
PlanetodeticRMAG Y Y

See Spacecraft.PlanetodeticRMAG. This parameter must be used with a CoordinateSystem with BodyFixed axes.

Data Type

Real

Dependency

CoordinateSystem (with BodyFixed axes)

Units

km
PlanetodeticVMAG Y Y

See Spacecraft.PlanetodeticVMAG. This parameter must be used with a CoordinateSystem with BodyFixed axes.

Data Type

Real

Dependency

CoordinateSystem (with BodyFixed axes)

Units

km/s
Q1 N Y

See Spacecraft.Q1

Data Type

Real

Dependency

(None)

Units

(None)
Q2 N Y

See Spacecraft.Q2

Data Type

Real

Dependency

(None)

Units

(None)
Q3 N Y

See Spacecraft.Q3

Data Type

Real

Dependency

(None)

Units

(None)
Q4 N Y

See Spacecraft.Q4

Data Type

Real

Dependency

(None)

Units

(None)
Quaternion Y N

Attitude quaternion.

Data Type

Array (1×4)

Dependency

(None)

Units

(None)
RA Y Y

See Spacecraft.RA

Data Type

Real

Dependency

CoordinateSystem

Output Range

-180° ≤ RA ≤ 180°

Units

deg
RAAN Y Y

See Spacecraft.RAAN

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ RAAN < 360°

Units

deg
RadApo Y Y

See Spacecraft.RadApo

Data Type

Real

Dependency

CelestialBody

Units

km
RadPer Y Y

See Spacecraft.RadPer

Data Type

Real

Dependency

CelestialBody

Units

km
RAV Y Y

See Spacecraft.RAV

Data Type

Real

Dependency

CoordinateSystem

Output Range

-180° ≤ RAV ≤ 180°

Units

deg
RLA N Y

Right ascension of the outgoing hyperbolic asymptote.

Data Type

Real

Dependency

CoordinateSystem

Output Range

-180° ≤ RLA ≤ 180°

Units

deg
RMAG Y Y

See Spacecraft.RMAG

Data Type

Real

Dependency

CelestialBody

Units

km
SemilatusRectum Y Y

See Spacecraft.SemilatusRectum

Data Type

Real

Dependency

CelestialBody

Units

km
SemilatusRectum N Y

Semilatus rectum of the osculating orbit.

Data Type

Real

Dependency

CelestialBody

Units

km
SMA Y Y

See Spacecraft.SMA

Data Type

Real

Dependency

CelestialBody

Units

km
SRPArea Y Y

See Spacecraft.SRPArea

Data Type

Real

Dependency

(None)

Units

m2
TA Y Y

See Spacecraft.TA.

Data Type

Real

Dependency

CelestialBody

Output Range

0° ≤ TA < 360°

Units

deg
TAIGregorian Y N

Spacecraft epoch in the TAI system and the Gregorian format.

Data Type

String

Dependency

(None)

Units

(N/A)
TAIModJulian Y Y

Spacecraft epoch in the TAI system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
TDBGregorian Y N

Spacecraft epoch in the TDB system and the Gregorian format.

Data Type

String

Dependency

(None)

Units

(N/A)
TDBModJulian Y Y

Spacecraft epoch in the TDB system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
TLONG Y Y

See Spacecraft.TLONG

Data Type

Real

Dependency

CoordinateSystem

Output Range

0° ≤ TLONG < 360°

Units

deg
TotalMass N Y

Total mass, including fuel mass from attached ChemicalTank resources.

Data Type

Real

Dependency

(None)

Units

kg
TTGregorian Y N

Spacecraft epoch in the TT system and the Gregorian format.

Data Type

String

Dependency

(None)

Units

(N/A)
TTModJulian Y Y

Spacecraft epoch in the TT system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
UTCGregorian Y N

Spacecraft epoch in the UTC system and the Gregorian format.

Data Type

String

Dependency

(None)

Units

(N/A)
UTCModJulian Y Y

Spacecraft epoch in the UTC system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
VelApoapsis N Y

Scalar velocity at apoapsis.

Data Type

Real

Dependency

CelestialBody

Units

km/s
VelPeriapsis N Y

Scalar velocity at periapsis.

Data Type

Real

Dependency

CelestialBody

Units

km/s
VMAG Y Y

See Spacecraft.VMAG

Data Type

Real

Dependency

CoordinateSystem

Output Range

Units

km/s
VX Y Y

See Spacecraft.VX

Data Type

Real

Dependency

CoordinateSystem

Units

km/s
VY Y Y

See Spacecraft.VY

Data Type

Real

Dependency

CoordinateSystem

Units

km/s
VZ Y Y

See Spacecraft.VZ

Data Type

Real

Dependency

CoordinateSystem

Units

km/s
X Y Y

See Spacecraft.X

Data Type

Real

Dependency

CoordinateSystem

Units

km
Y Y Y

See Spacecraft.Y

Data Type

Real

Dependency

CoordinateSystem

Units

km
Z Y Y

See Spacecraft.Z

Data Type

Real

Dependency

CoordinateSystem

Units

km

FuelTank

ChemicalTank parameters are accessible only after attaching the ChemicalTank resource to a Spacecraft, like so:

          Create FuelTank aTank
Create Spacecraft aSat
aSat.Tanks = {aTank}

Then, ChemicalTank parameters are accessible by specifying the ChemicalTank name as the parameter dependency:

          Create ReportFile aReport
aReport.Add = {aSat.aTank.FuelMass}
Parameter Settable Plottable Description
FuelDensity Y Y

See ChemicalTank.FuelDensity

Data Type

Real

Dependency

(None)

Units

kg/m3
FuelMass Y Y

See ChemicalTank.FuelMass

Data Type

Real

Dependency

(None)

Units

kg
Pressure Y Y

See ChemicalTank.Pressure

Data Type

Real

Dependency

(None)

Units

kPa
RefTemperature Y Y

See ChemicalTank.RefTemperature

Data Type

Real

Dependency

(None)

Units

°C
Temperature Y Y

See ChemicalTank.Temperature

Data Type

Real

Dependency

(None)

Units

°C
Volume Y Y

See ChemicalTank.Volume

Data Type

Real

Dependency

(None)

Units

m3

Space Point Parameters

All Resources that have coordinates in space have Cartesian position and velocity parameters, so you can access ephemeris information. This includes all built-in solar system bodies and other Resources such as CelestialBody,Planet, Moon, Asteroid, Comet, Barycenter, LibrationPoint, and GroundStation :

  • CelestialBody.CoordinateSystem.X

  • CelestialBody.CoordinateSystem.Y

  • CelestialBody.CoordinateSystem.Z

  • CelestialBody.CoordinateSystem.VX

  • CelestialBody.CoordinateSystem.VY

  • CelestialBody.CoordinateSystem.VZ

Warning

Note that to use these parameters, you must first set the epoch of the Resource to the desired epoch at which you want the data. Additionally, the epoch should be set after the BeginMissionSequence Command. See the following example.

          Create ReportFile rf

BeginMissionSequence

Luna.Epoch.A1ModJulian = 21545
Report rf Luna.EarthMJ2000Eq.X Luna.EarthMJ2000Eq.Y Luna.EarthMJ2000Eq.Z ...
       Luna.EarthMJ2000Eq.VX Luna.EarthMJ2000Eq.VY Luna.EarthMJ2000Eq.VZ

Note

Spacecraft parameters are treated slightly different than Space Point parameters primarly because Spacecraft Cartesian state parameters are settable, and all other Space Point Cartesian parameters are only gettable. When requesting state information for Space Points other than Spacecraft, the coordinates are computed based on the model configured for that Resource. Additionally, not all epoch configuration options supported for Spacecraft are supported for Space Points (i.e. Epoch and DateFormat).

Parameter Settable Plottable Description
A1Gregorian Y N

Resource epoch in the A.1 system and the Gregorian format.

Data Type

String

Dependency

(None)

Units

(N/A)
A1ModJulian Y Y

Resource epoch in the A.1 system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
TAIGregorian Y N

Resource epoch in the TAI system and the Gregorian format.

Data Type

String

Dependency

(None)

Units

(N/A)
TAIModJulian Y Y

Resource epoch in the TAI system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
TDBGregorian Y N

Resource epoch in the TDB system and the Gregorian format.

Data Type

String

Dependency

(None)

Units

(N/A)
TDBModJulian Y Y

Resource epoch in the TDB system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
TTGregorian Y N

Resource epoch in the TT system and the Gregorian format.

Data Type

String

Dependency

(None)

Units

(N/A)
TTModJulian Y Y

Resource epoch in the TT system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
UTCGregorian Y N

Resource epoch in the UTC system and the Gregorian format.

Data Type

String

Dependency

(None)

Units

(N/A)
UTCModJulian Y Y

Resource epoch in the UTC system and the Modified Julian format.

Data Type

Real

Dependency

(None)

Units

d
VX N Y

The x-component of velocity with respect to the CoordinateSystem chosen as the dependency. When no dependency is selected, EarthMJ2000Eq is used.

Data Type

Real

Dependency

CoordinateSystem

Units

km/s
VY N Y

The y-component of velocity with respect to the CoordinateSystem chosen as the dependency. When no dependency is selected, EarthMJ2000Eq is used.

Data Type

Real

Dependency

CoordinateSystem

Units

km/s
VZ N Y

The z-component of velocity with respect to the CoordinateSystem chosen as the dependency. When no dependency is selected, EarthMJ2000Eq is used.

Data Type

Real

Dependency

CoordinateSystem

Units

km/s
X N Y

The x-component of position with respect to the CoordinateSystem chosen as the dependency. When no dependency is selected, EarthMJ2000Eq is used.

Data Type

Real

Dependency

CoordinateSystem

Units

km
Y N Y

The y-component of position with respect to the CoordinateSystem chosen as the dependency. When no dependency is selected, EarthMJ2000Eq is used.

Data Type

Real

Dependency

CoordinateSystem

Units

km
Z N Y

The z-component of position with respect to the CoordinateSystem chosen as the dependency. When no dependency is selected, EarthMJ2000Eq is used.

Data Type

Real

Dependency

CoordinateSystem

Units

km

Thruster

ChemicalThruster parameters are accessible only after attaching the ChemicalThruster resource to a Spacecraft, like so:

          Create Thruster aThruster
Create Spacecraft aSat
aSat.Thrusters = {aThruster}

Then, ChemicalThruster parameters are accessible by specifying the ChemicalThruster name as the parameter dependency:

          Create ReportFile aReport
aReport.Add = {aSat.aThruster.DutyCycle}

The table below shows reportable thruster based parameters:

Parameter Settable Plottable Description
C1 Y Y

See ChemicalThruster.C1

Data Type

Real

Dependency

(None)

Units

N
C2 Y Y

See ChemicalThruster.C2

Data Type

Real

Dependency

(None)

Units

N/kPa
C3 Y Y

See ChemicalThruster.C3

Data Type

Real

Dependency

(None)

Units

N
C4 Y Y

See ChemicalThruster.C4

Data Type

Real

Dependency

(None)

Units

N/kPa
C5 Y Y

See ChemicalThruster.C5

Data Type

Real

Dependency

(None)

Units

N/kPa2
C6 Y Y

See ChemicalThruster.C6

Data Type

Real

Dependency

(None)

Units

N/kPaC7
C7 Y Y

See ChemicalThruster.C7

Data Type

Real

Dependency

(None)

Units

(None)
C8 Y Y

See ChemicalThruster.C8

Data Type

Real

Dependency

(None)

Units

N/kPaC9
C9 Y Y

See ChemicalThruster.C9

Data Type

Real

Dependency

(None)

Units

(None)
C10 Y Y

See ChemicalThruster.C10

Data Type

Real

Dependency

(None)

Units

N/kPaC11
C11 Y Y

See ChemicalThruster.C11

Data Type

Real

Dependency

(None)

Units

(None)
C12 Y Y

See ChemicalThruster.C12

Data Type

Real

Dependency

(None)

Units

N
C13 Y Y

See ChemicalThruster.C13

Data Type

Real

Dependency

(None)

Units

(None)
C14 Y Y

See ChemicalThruster.C14

Data Type

Real

Dependency

(None)

Units

1/kPa
C15 Y Y

See ChemicalThruster.C15

Data Type

Real

Dependency

(None)

Units

(None)
C16 Y Y

See ChemicalThruster.C16

Data Type

Real

Dependency

(None)

Units

1/kPa
DutyCycle Y Y

See ChemicalThruster.DutyCycle

Data Type

Real

Dependency

(None)

Units

(None)
GravitationalAccel Y Y

See ChemicalThruster.GravitationalAccel

Data Type

Real

Dependency

(None)

Units

m/s2
Isp Y Y

Specific impulse of an individual thruster. When thruster(s) is not turned on, GMAT will report zeros to a report file.

Data Type

Real

Dependency

(None)

Units

s
K1 Y Y

See ChemicalThruster.K1

Data Type

Real

Dependency

(None)

Units

s
K2 Y Y

See ChemicalThruster.K2

Data Type

Real

Dependency

(None)

Units

s/kPa
K3 Y Y

See ChemicalThruster.K3

Data Type

Real

Dependency

(None)

Units

s
K4 Y Y

See ChemicalThruster.K4

Data Type

Real

Dependency

(None)

Units

s/kPa
K5 Y Y

See ChemicalThruster.K5

Data Type

Real

Dependency

(None)

Units

s/kPa2
K6 Y Y

See ChemicalThruster.K6

Data Type

Real

Dependency

(None)

Units

s/kPaC7
K7 Y Y

See ChemicalThruster.K7

Data Type

Real

Dependency

(None)

Units

(None)
K8 Y Y

See ChemicalThruster.K8

Data Type

Real

Dependency

(None)

Units

s/kPaC9
K9 Y Y

See ChemicalThruster.K9

Data Type

Real

Dependency

(None)

Units

(None)
K10 Y Y

See ChemicalThruster.K10

Data Type

Real

Dependency

(None)

Units

s/kPaC11
K11 Y Y

See ChemicalThruster.K11

Data Type

Real

Dependency

(None)

Units

(None)
K12 Y Y

See ChemicalThruster.K12

Data Type

Real

Dependency

(None)

Units

s
K13 Y Y

See ChemicalThruster.K13

Data Type

Real

Dependency

(None)

Units

(None)
K14 Y Y

See ChemicalThruster.K14

Data Type

Real

Dependency

(None)

Units

1/kPa
K15 Y Y

See ChemicalThruster.K15

Data Type

Real

Dependency

(None)

Units

(None)
K16 Y Y

See ChemicalThruster.K16

Data Type

Real

Dependency

(None)

Units

1/kPa
MassFlowRate N Y

Mass flow rate from an individual thruster. When thruster(s) is not turned on, GMAT will report zeros to a report file.

Data Type

Real

Dependency

(None)

Units

kg/s
ThrustDirection1 Y Y

See ChemicalThruster.ThrustDirection1

Data Type

Real

Dependency

(None)

Units

(None)
ThrustDirection2 Y Y

See ChemicalThruster.ThrustDirection2

Data Type

Real

Dependency

(None)

Units

(None)
ThrustDirection3 Y Y

See ChemicalThruster.ThrustDirection3

Data Type

Real

Dependency

(None)

Units

(None)
ThrustMagnitude Y Y

Magnitude of the thrust from an individual thruster. When thruster(s) is not turned on, GMAT will report zeros to a report file.

Data Type

Real

Dependency

(None)

Units

Newtons
ThrustScaleFactor Y Y

See ChemicalThruster.ThrustScaleFactor

Data Type

Real

Dependency

(None)

Units

(None)

ImpulsiveBurn

To compute ImpulsiveBurn parameters, GMAT requires that an ImpulsiveBurn has been executed using a Maneuver command like this:

          Maneuver myImpulsiveBurn(mySat)

In the case that an ImpulsiveBurn has not been applied, GMAT will output zeros for the ImpulsiveBurn components and issue a warning.

We recommended that you evaluate ImpulsiveBurn parameters immediately after the ImpulsiveBurn is applied using the Maneuver command like this:

          Maneuver myImpulsiveBurn(mySat) 
myVar =  mySat.MyCoordinateSystem.Element1

The above usage avoids issues that may occur if the ImpulsiveBurn coordinate system is time varying, and the ImpulsiveBurn parameters are requested after further manipulation of the participants using other commands (such as Propagate). In that case, it is possible that the participants are no longer at the epoch of the maneuver, and unexpected results can occur due to epoch mismatches.

Parameter Settable Plottable Description
B Y Y

See ImpulsiveBurn.B

Data Type

Real

Dependency

(None)

Units

(None)
Element1 Y Y

See ImpulsiveBurn.Element1

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
Element2 Y Y

See ImpulsiveBurn.Element2

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
Element3 Y Y

See ImpulsiveBurn.Element3

Data Type

Real

Dependency

CoordinateSystem

Units

(None)
N Y Y

See ImpulsiveBurn.N

Data Type

Real

Dependency

(None)

Units

(None)
V Y Y

See ImpulsiveBurn.V

Data Type

Real

Dependency

(None)

Units

(None)

FiniteBurn

To compute FiniteBurn parameters, GMAT requires that a FiniteBurn has been executed using a BeginFiniteBurn command like this:

          BeginFiniteBurn Maneuver myFiniteBurn(mySat)

In the case that a FiniteBurn has not been applied, GMAT will output zeros for all reportable FiniteBurn parameters to a report file. All finite burn parameters will report zeros whenever a finite burn is not turned on. The table below shows reportable finite burn parameters:

Parameter Settable Plottable Description
TotalAcceleration1 N Y

First component of the total acceleration from all thrusters in the three coordinate directions of a J2000 system. Zero is reported whenever thruster is not turned on

Data Type

Real

Dependency

(None)

Units

Km/s2
TotalAcceleration2 N Y

Second component of the total acceleration from all thrusters in the three coordinate directions of a J2000 system. Zero is reported whenever thruster is not turned on

Data Type

Real

Dependency

(None)

Units

Km/s2
TotalAcceleration3 N Y

Third component of the total acceleration from all thrusters in the three coordinate directions of a J2000 system. Zero is reported whenever thruster is not turned on

Data Type

Real

Dependency

(None)

Units

Km/s2
TotalMassFlowRate N Y

Total mass flow rate from all thrusters. Zero is reported whenever thruster is not turned on

Data Type

Real

Dependency

(None)

Units

Kg/s
TotalThrust1 N Y

First component of the total thrust from all thrusters in the three coordinate directions of a J2000 system. Zero is reported whenever thruster is not turned on

Data Type

Real

Dependency

(None)

Units

Newtons
TotalThrust2 N Y

Second component of the total thrust from all thrusters in the three coordinate directions of a J2000 system. Zero is reported whenever thruster is not turned on

Data Type

Real

Dependency

(None)

Units

Newtons
TotalThrust3 N Y

Third component of the total thrust from all thrusters in the three coordinate directions of a J2000 system. Zero is reported whenever thruster is not turned on

Data Type

Real

Dependency

(None)

Units

Newtons

Solver

Solver parameters allow you to query a Solver for its convergence state to determine if the Solver converged. There are both string and numeric parameters which are described in further detail in the table below the following usage example using solver parameters before and after a Target sequence.

          Create Spacecraft aSat
Create Propagator aPropagator

Create ImpulsiveBurn aBurn
Create DifferentialCorrector aDC
Create OrbitView EarthView
EarthView.Add = {Earth,aSat}
EarthView.ViewScaleFactor = 5

Create ReportFile aReport

BeginMissionSequence
Report aReport aDC.SolverStatus aDC.SolverState
Target aDC
   Vary aDC(aBurn.Element1 = 1.0, {Upper = 3})
   Maneuver aBurn(aSat)
   Propagate aPropagator(aSat,{aSat.Apoapsis})
   Achieve aDC(aSat.RMAG = 42164)
EndTarget
Report aReport aDC.SolverStatus aDC.SolverState
Parameter Settable Plottable Description
SolverStatus N N

The SolverStatus parameter contains the state of a Solver. If the Solver has not executed, SolverStatus is Initialized. If the Solver has executed and converged, SolverStatus is Converged. If the Solver is iterating, SolverStatus is Running. If the Solver has executed and reached the maximum number of iterations before convergence, SolverStatus is ExceededIterations. If the Solver has executed and failed to converge, but did not exceed the maximum iterations, SolverStatus is DidNotConverge.

Data Type

String

Dependency

(None)

Units

(None)
SolverState N Y

The SolverState parameter contains the state of a Solver. If the solver has not executed, SolverState is 0. If the Solver has executed and converged, SolverState is 1. If the Solver is iterating, SolverState is 0. If the Solver has executed and reached the maximum number of iterations before convergence, SolverState is -1. If the Solver has executed and failed to converge, but did not exceed the maximum iterations, SolverState is -2.

Data Type

Integer

Dependency

(None)

Units

(None)

Array, String, Variable

Array, String, and Variable resources are themselves parameters, and can be used as any other parameter would. All of these are writable parameters, though only Variable resources and individual elements of Array resources can be plotted.

Examples

Using parameters in the Mission Sequence:

          Create Spacecraft aSat
Create Propagator aProp
Create ReportFile aReport
Create Variable i

BeginMissionSequence

% propagate for 100 steps
For i=1:100
Propagate aProp(aSat)
% write four parameters (one standalone, three coordinate-system-dependent) to a file
Report aReport aSat.TAIGregorian aSat.EarthFixed.X aSat.EarthFixed.Y aSat.EarthFixed.Z
EndFor

Using parameters as plot data:

          Create Spacecraft aSat
Create Propagator aProp

Create XYPlot aPlot
aPlot.XVariable = aSat.TAIModJulian
aPlot.YVariables = {aSat.Earth.Altitude, aSat.Earth.ECC}

Create Variable i

BeginMissionSequence

% propagate for 100 steps
For i=1:100
    Propagate aProp(aSat)
EndFor

Using parameters as stopping conditions:

          Create Spacecraft aSat
aSat.SMA = 6678

Create ForceModel anFM
anFM.Drag.AtmosphereModel = MSISE90

Create Propagator aProp
aProp.FM = anFM

BeginMissionSequence

Propagate aProp(aSat) {aSat.Earth.Altitude = 100, aSat.ElapsedDays = 365}
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