Name

Description

Attributes

A

The Keplerian semimajor axis (a). Half the length of the long axis of the orbit ellipse. Can not be set to 0.

Type: Variable
Access: Read/Write
Units: km

Acceleration

Returns the vector of the Spacecraft's instantaneous acceleration referenced to the ICRF. This vector provides the Cartesian components of the change in the Spacecraft's velocity with respect to time. The components of this vector are populated using the ForceModel associated with the Spacecraft's Propagator and will be zero if an analytic propagator is used.

Type: Array
Access: ReadOnly
Units: km/s^2

Accelerations

The accelerations due to various forces on the spacecraft, referenced to the ICRF.

Type: Array of AccelerationTerm
Access: ReadOnly

AHF

AHF for advancing the attitude of the Spacecraft.

Type: Ephemeris
Access: ReadOnly

AlphaRE

Returns the angle between the Spacecraft's +Y body axis and the projection of the spacecraftearth line on the spacecraft's YZ body plane.

Type: Variable
Access: ReadOnly
Units: deg

AlphaRS

Returns the angle between the Spacecraft's +Y body axis and the projection of the sunspacecraft line on spacecraft's YZ body plane.

Type: Variable
Access: ReadOnly
Units: deg

AlphaTE

Returns the angle between the spacecraftearth line and the Spacecraft's +X body axis.

Type: Variable
Access: ReadOnly
Units: deg

AlphaTS

Returns the angle between the sunspacecraft line and the Spacecraft's +X body axis.

Type: Variable
Access: ReadOnly
Units: deg

AngularAcceleration

The angular acceleration vector that is associated with the quaternion attitude system. When using a Spinner attitude system the angular acceleration is populated with values; which will be nonzero if you have a nonzero nutation angle, and the Spacecraft moment of inertia Ixx != Iyy != Izz.

Type: Array
Access: ReadOnly
Units: deg/s^2

AngularMomentumDeclination

The declination of the angular momentum vector with respect to the ICRF for a spinning Spacecraft. AngularMomentumRightAscension and AngularMomentumDeclination define the orientation of the "angular momentum frame" with respect to the ICRF. The zaxis of the angular momentum frame is coincident with the spinning Spacecraft's angular momentum vector.

Type: Variable
Access: Read/Write
Units: deg

AngularMomentumRightAscension

The right ascension of the angular momentum vector with respect to the ICRF for a spinning Spacecraft.

Type: Variable
Access: Read/Write
Units: deg

AngularVelocity

The angular velocity vector associated with the quaternion attitude system. The angular velocity will be applied with respect to the attitude frame defined by the Spacecraft.AttitudeRefFrame property.

Type: Array
Access: Read/Write
Units: deg/s

Annotation

When displayed in a Mission View the specified text will be drawn at each tail point. The value may be modified between updates to change the text drawn at subsequent points.

Type: String
Access: Read/Write

Apoapsis

Returns an instantaneous osculating estimate of the apoapsis distance from the center of the CentralBody to the Spacecraft, based on the current orbital state. The Spacecraft.Apoapsis property is not based on a force model and is computed directly from the instantaneous Keplerian elements where the instantaneous Keplerian elements are computed from the active state of the Spacecraft.

Type: Variable
Access: ReadOnly
Units: km

Apogee

Returns an instantaneous osculating estimate of the apoapsis distance from the center of its central body to the Spacecraft, based on the current orbital state. The Spacecraft.Apogee property is not based on a force model and is computed directly from the instantaneous Keplerian elements where the instantaneous Keplerian elements are computed from the active state of the Spacecraft.

Type: Variable
Access: ReadOnly
Units: km

ApogeeHeight

Returns the instantaneous osculating apoapsis height of the Spacecraft above its central body, measured along a vector normal to the surface of the body at the Spacecraft's subsatellite point. The oblateness of the central body is taken into account when calculating the height.

Type: Variable
Access: ReadOnly
Units: km

ArgumentOfLatitude

Returns the angle between the vector pointing to the ascending node and the vector pointing to the Spacecraft's current position. This angle varies from 0 to 360 degrees.

Type: Variable
Access: ReadOnly
Units: deg

AscendingNode

This method can be used with the Step command to advance the Spacecraft to the point in its orbit at which the Spacecraft crosses its central body's instantaneous equatorial plane, moving from the south to the north. It serves as the conditional statement for the "to" statement that can be used with the Step command.

Type: Variable
Access: ReadOnly
Units: km

AttitudeCoordinateSystem

CoordinateSystem that serves as the attitude reference frame for the Spacecraft object.

Type: CoordinateSystem
Access: ReadOnly

AttitudeMatrix

The DirectionCosineMatrix (DCM) that defines the rotation from the specified Attitude Reference Frame to the Spacecraft Body Coordinate System.

Type: Matrix
Access: Read/Write

AttitudeRefFrame

This is the Spacecraft's attitude reference frame. It is necessary to define the AttitudeRefFrame property of the spacecraft prior to defining the attitude system properties.

Type: String
Access: Read/Write

AttitudeSystem

Specifies which attitude system set defines the Spacecraft state.

Type: String
Access: Read/Write

BetaAngle

Returns the elevation angle measured between the orbital plane and the CentralBodySun vector. Note that the orbital plane is defined by the orbital momentum vector evaluated in the ICRF.

Type: Variable
Access: ReadOnly
Units: deg

BL_A

The mean semimajor axis in the BrouwerLyddane Mean Element set. Half the length of the long axis of the orbit ellipse.

Type: Variable
Access: Read/Write
Units: km

BL_E

The mean eccentricity in the BrouwerLyddane Mean Element set. The distance from the center of the ellipse to one of the foci divided by the semimajor axis.

Type: Variable
Access: Read/Write

BL_Elements

Represents the instantaneous Spacecraft orbital state as BrouwerLyddane Mean Keplerian elements. The Spacecraft state is reported as the following mean element set semimajor axis, eccentricity, inclination, right ascension of ascending node, argument of perigee, and mean anomaly.

Type: Array
Access: Read/Write

BL_I

The mean inclination in the BrouwerLyddane Mean Element set. The angle between the orbit plane and the fundamental plane of the ICRF.

Type: Variable
Access: Read/Write
Units: deg

BL_MA

Mean Anomaly of the Spacecraft referenced to the ICRF in the BrouwerLyddane Mean Element set. The Mean Anomaly is defined as the angle from the Eccentricity Vector to a position vector corresponding to the location of the satellite if it always moved at a constant angular rate.

Type: Variable
Access: Read/Write
Units: deg

BL_RAAN

The mean right ascension of the ascending node in the BrouwerLyddane Mean Element set. The angle, measured at the center of the Earth, from the vernal equinox to the ascending node. The ascending node is the point where the satellite crosses the fundamental plane of the ICRF going from south to north.

Type: Variable
Access: Read/Write
Units: deg

BL_W

The mean argument of perigee in the BrouwerLyddane Mean Element set. The angle, measured at the center of the Earth, from the ascending node. The point in the satellites orbit closest to the Earth.

Type: Variable
Access: Read/Write
Units: deg

BLJ2A

Mean SemiMajor Axis in the J2 BrouwerLyddane Element set, which is calculated using only the J2 zonal harmonic coefficient in the BrouwerLyddane conversion.

Type: Variable
Access: Read/Write
Units: km

BLJ2E

Mean Eccentricity, in the J2 BrouwerLyddane Element set, which is calculated using only the J2 zonal harmonic coefficient in the BrouwerLyddane conversion. The Eccentricity is a dimensionless value that defines the shape of the Spacecraft's orbit.

Type: Variable
Access: Read/Write

BLJ2Elements

Represents the instantaneous Spacecraft orbital state as BrouwerLyddane Mean Keplerian elements, where ONLY the J2 zonal harmonic coefficient is used in the conversion. The Spacecraft state is reported as the following mean element set semimajor axis, eccentricity, inclination, right ascension of ascending node, argument of perigee, and mean anomaly.

Type: Array
Access: Read/Write

BLJ2I

Mean Inclination in the J2 Brouwer Lyddane Element set, which is calculated using only the J2 zonal harmonic coefficient in the BrouwerLyddane conversion. The Inclination is defined by the angle between the orbit plane and the fundamental plane of the ICRF.

Type: Variable
Access: Read/Write
Units: deg

BLJ2MA

Mean Anomaly in the J2 Brouwer Lyddane Element set, which is calculated using only the J2 zonal harmonic coefficient in the BrouwerLyddane conversion, and referenced to the ICRF. The Mean Anomaly is defined as the angle from the eccentricity vector to a position vector corresponding to the location of the satellite if it is always moved at a constant angular rate.

Type: Variable
Access: Read/Write
Units: deg

BLJ2RAAN

Mean Right Ascension of the Ascending Node in the J2 Brouwer Lyddane Element set, which is calculated using only the J2 zonal harmonic coefficient in the BrouwerLyddane conversion, and referenced to the ICRF.

Type: Variable
Access: Read/Write
Units: deg

BLJ2W

Mean Argument of Perigee in the J2 Brouwer Lyddane Element set, which is calculated using only the J2 zonal harmonic coefficient in the BrouwerLyddane conversion, and referenced to the ICRF. The Argument of Perigee is defined by the angle measured at the center of the Earth in the orbit plane, from the ascending node to perigee.

Type: Variable
Access: Read/Write
Units: deg

BodyScale

A scale factor to increase or decrease the size of the Spacecraft model in a Mission View. The BodyScale property assumes the model dimensions are in units of meters, similar to the ThreeDModel.Scale property. If, for example, the ThreeDModel.Scale is set to 1, the Spacecraft.BodyScale will have to be set to 1 in order to make bounding boxes coincide with the model.

Type: Variable
Access: Read/Write

C3

Returns the characteristic energy of the calling Spacecraft relative to its CentralBody. The characteristic energy is a measure of the excess specific energy over that required to escape from the CentralBody. For a Spacecraft in a nonescape trajectory, the characteristic energy will be less than 0. For a Spacecraft in a parabolic trajectory, the characteristic energy will be equal to 0. A Spacecraft in a hyperbolic trajectory will have a characteristic energy that is equal to the Hyperbolic Excess Velocity squared.

Type: Variable
Access: ReadOnly
Units: km^2/s^2

Cd

The Coefficient of Drag is a property that is a function of the properties and shape of the spacecraft's area incident to the velocity direction. It is used in the calculation of the force on the spacecraft due to atmospheric Drag.

Type: Variable
Access: Read/Write

CenterOfMass

Returns the X, Y, and Z components of the center of mass of the dry Spacecraft and all attached Tanks. The Spacecraft's center of mass is updated during maneuvers as fuel is depleted from the tanks. The center of mass location is relative to the origin of the Spacecraft body fixed coordinate frame.

Type: Array
Access: ReadOnly
Units: m

CentralBody

Name of the body that defines the origin of the Spacecraft's position and velocity. This can be a userdefined CelestialObject or one of the following predefined bodies:
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
Moon
Sun
In order to translate the origin of a Spacecraft's state to a different central body, simply change the Spacecraft.CentralBody property.

Type: String
Access: Read/Write

CentralBodyObject

CelestialObject that defines the origin for the Spacecraft's position and velocity.

Type: CelestialObject
Access: ReadOnly

Cl

The Coefficient of Lift is a property that is a function of the properties and shape of the spacecraft's area incident to the velocity direction. It is used in the calculation of the force on the spacecraft due to aerodynamic Lift.

Type: Variable
Access: Read/Write

CoElevation

The initial right ascension (not coelevation) of a spinning Spacecraft's spin axis with respect to the angular momentum frame. NutationAngle and CoElevation define the orientation of the "spin frame" with respect to the "angular momentum frame".
The zaxis of the spin frame is coincident with the spinning Spacecraft's spin axis.

Type: Variable
Access: Read/Write
Units: deg

Color

The color of the Spacecraft tail when displayed in a Mission View. The color can be overridden for an individual view using the ViewWindow.SetObjectColor() method.

Type: Variable
Access: Read/Write

Cr

The Coefficient of Reflectivity is a property that is a function of the properties of the spacecraft's area incident to the SunEarth line. It is used in the calculation of the force on the spacecraft due to solar radiation pressure.
Note that this value is only used when ForceModel.SRPForceGeometry is set to spherical. If using a plate model, the coefficients of reflectivity should be set for each individual plate.

Type: Variable
Access: Read/Write

DayOfMonth

Returns the numerical value representing the calendar day of the month for the current spacecraft Epoch. The day is given as an integer number ranging from 1 to 31.

Type: Variable
Access: ReadOnly

DayOfWeek

Returns the numerical value representing a day of the week for the current spacecraft Epoch. The day is given as an integer number ranging from 1 to 7, where 1 corresponds to Sunday.

Type: Variable
Access: ReadOnly

DayOfYear

Returns the numerical value representing the current day of year counted from January 1 of the current year for the current spacecraft Epoch. The day is given as an integer number ranging from 1 to 365 (366 for leap years).

Type: Variable
Access: ReadOnly

DEC

The declination of the satellite in the Spherical Element set. It is defined as the angle between the satellite position vector and the fundamental plane of the ICRF.

Type: Variable
Access: Read/Write
Units: deg

DeclaredName

The name of the object as declared.

Type: String
Access: ReadOnly

Density

Represents the density of the atmosphere at the Spacecraft's altitude calculated using the defined atmospheric density model associated with the Spacecraft's ForceModel.

Type: Variable
Access: ReadOnly
Units: kg/km^3

DescendingNode

This method can be used with the Step command to advance the Spacecraft to the point in its orbit at which the Spacecraft crosses its central body's instantaneous equatorial plane, moving from the north to the south. It serves as the conditional statement for the "to" statement that can be used with the Step command.

Type: Variable
Access: ReadOnly
Units: km

DisplayName

The name displayed for this object in output windows such as views, plots, and reports.

Type: String
Access: Read/Write

Drag

Represents the instantaneous force on the Spacecraft due to atmospheric drag modeling, calculated using the defined atmospheric density model associated with the Spacecraft's ForceModel. Returns zero if Drag is not enabled.

Type: Array
Access: ReadOnly
Units: N

DragArea

The Drag Area is the incident cross sectional area to the velocity direction. It is used in the calculation of the force on the spacecraft due to atmospheric Drag.

Type: Variable
Access: Read/Write
Units: m^2

E

The Keplerian eccentricity (e). A unitless property that describes the curvature of an ellipse. The distance from the center of the ellipse to one of the foci divided by the semimajor axis.

Type: Variable
Access: Read/Write

EA

Represents the instantaneous Eccentric Anomaly of the Spacecraft. The Eccentric Anomaly is an angle related to the position of the spacecraft and the ideal orbit associated with its orbit (ie the circular orbit which inscribes the true elliptical orbit)

Type: Variable
Access: ReadOnly
Units: deg

EDR

Represents the instantaneous Energy Dissipation Rate of the Spacecraft due to atmospheric drag modeling, calculated using the defined atmospheric density model associated with the Spacecraft's ForceModel. Returns zero if Drag is not enabled.

Type: Variable
Access: ReadOnly
Units: W/kg

ElapsedTime

Returns the time passed since the first time this property is read on a specific line of script.

Type: TimeSpan
Access: ReadOnly
Units: day

ElectronDensity

Returns the number of Electrons per m^3 at the Spacecraft location. The Electron Density is calculated using the Ionosphere model type and properties specified in the Ionosphere Options within the Solar System.

Type: Variable
Access: ReadOnly
Units: 1/m^3

ElementType

Determines which element set defines the Spacecraft state. The chosen element set will determine the properties that are written to an external file when using the Put Command. A FreeFlyer ephemeris always contains Cartesian elements despite the value of this property.

Type: String
Access: Read/Write

Energy

Represents the instantaneous specific energy (energy per unit mass) of the Spacecraft orbit. This is calculated based on the Keplerian gravitational potential model as Energy = mu/(2*a).

Type: Variable
Access: ReadOnly
Units: km^2/s^2

Epoch

The current Spacecraft date and time in International Atomic Time (TAI) in the Modified Julian Date format. The returned value has units of days, measured from January 5, 1941 at 12:00:00.000 TAI.
Changing the value of this property does not cause the Spacecraft's state to be propagated  the Spacecraft's state will not be changed. In order to propagate a Spacecraft to a desired epoch, use the Step command.

Type: TimeSpan
Access: Read/Write
Units: day

EpochTAI

Returns the current spacecraft date and time in International Atomic Time (TAI) in the Modified Julian Date format as measured from January 5, 1941 at 12:00:00.000 TAI.

Type: TimeSpan
Access: ReadOnly
Units: day

EpochText

The current Spacecraft date and time in Coordinated Universal Time (UTC). The returned time is in the Gregorian time format of "Mmm DD YYYY HH:MM:SS.SSS", where Mmm stands for the first three (3) letters of the month; DD stands for the day of month; YYYY stands for the 4digit year; for millisecond mode, HH:MM:SS.SSS refers to hours, minutes, and seconds to milliseconds; and for nanosecond mode HH:MM:SS.SSSSSSSSS refers to hours, minutes, and seconds to nanoseconds.

Type: String
Access: ReadOnly

EpochUSNO

Returns the current spacecraft date and time in International Atomic Time (TAI) in the Modified Julian Date format as measured by the United States Naval Observatory from November 17, 1858 00:00:00.000 TAI.

Type: TimeSpan
Access: ReadOnly
Units: day

EpochUT1

Returns the current Spacecraft date and time in Universal Time (UT1) in the Modified Julian Date format.

Type: TimeSpan
Access: ReadOnly
Units: day

EpochUTC

Returns the current Spacecraft date and time in Coordinated Universal Time (UTC) in the Modified Julian Date format.

Type: TimeSpan
Access: ReadOnly
Units: day

EquinoctialA

The a component of the Equinoctial element set. Half the length of the long axis of the orbit ellipse.

Type: Variable
Access: Read/Write
Units: km

EquinoctialH

The h component of the Equinoctial element set, defined by: h = e*sin(RAAN + w), where e, w, and RAAN are the Keplerian Eccentricity, Argument of Perigee and Right Ascension of the Ascending Node respectively. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

EquinoctialK

The k component of the Equinoctial element set, defined by: k = e*cos(RAAN + w), where e, w, and RAAN are the Keplerian Eccentricity, Argument of Perigee and Right Ascension of the Ascending Node respectively. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

EquinoctialLongitude

Equinoctial Longitude defined by the mean longitude, defined as: RAAN + w + MA, where RAAN and w are the Right Ascension of the Ascending Node and the Argument of Perigee, respectively, and MA is the Keplerian mean anomaly. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write
Units: deg

EquinoctialP

The p component of the Equinoctial element set, defined by: p = tan(i/2)sin(RAAN), where i is the orbit inclination and RAAN is the Keplerian Right Ascension of the Ascending Node. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

EquinoctialQ

The q component of the Equinoctial element set, defined by: q = tan(i/2)cos(RAAN) where i is the orbit inclination and RAAN is the Keplerian Right Ascension of the Ascending Node. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

EulerAngles

These are the angles associated with the Euler attitude system. These angles will be applied as a set of three rotations to the Spacecraft's attitude about the axes set in the Spacecraft.EulerSequence property.

Type: Array
Access: Read/Write
Units: deg

EulerAnglesICRF

Returns the three Euler Angles that define the orientation of the Spacecraft Body Coordinate System with respect to the ICRF. This property does not affect the Euler Angle Sequence. Please use Spacecraft.EulerSequence to set the Euler Angle rotation sequence.

Type: Array
Access: ReadOnly
Units: deg

EulerAnglesLVLH

Returns the three Euler Angles that define the orientation of the Spacecraft Body Coordinate System with respect to the LVLH frame of the spacecraft. This property does not affect the Euler Angle Sequence. Please use Spacecraft.EulerSequence to set the Euler Angle rotation sequence.

Type: Array
Access: ReadOnly
Units: deg

EulerAnglesRIC

Returns the three Euler Angles that define the orientation of the Spacecraft BodyCoordinateSystem with respect to the RIC frame of the spacecraft. This property does not affect the Euler Angle Sequence. Please use Spacecraft.EulerSequence to set the Euler Angle rotation sequence.

Type: Array
Access: ReadOnly
Units: deg

EulerAnglesUVW

Returns the three Euler Angles that define the orientation of the Spacecraft Body Coordinate System with respect to the UVW frame of the spacecraft. This property does not affect the Euler Angle Sequence. Please use Spacecraft.EulerSequence to set the Euler Angle rotation sequence.

Type: Array
Access: ReadOnly
Units: deg

EulerRates

Rate of change of the Euler angles.

Type: Array
Access: Read/Write
Units: deg/s

EulerSequence

Axes of rotation that the EulerAngles are around.

Type: Array
Access: Read/Write

EVector

Represents the instantaneous eccentricity vector referenced to the ICRF. The eccentricity vector points from the center of the central body toward perigee with a magnitude equal to the eccentricity of the orbit.

Type: Array
Access: ReadOnly

FixedPosition

Reports the object's position components (X, Y, Z) referenced to the Body Fixed coordinate system of its central body.

Type: Array
Access: ReadOnly
Units: km

FixedVelocity

Reports the Spacecraft's velocity components (VX, VY, VZ) referenced to the Body Fixed coordinate system of its central body.

Type: Array
Access: ReadOnly
Units: km/s

ForceCoefficientType

Flag indicating whether Cd and Cr are used in the physical model, or B* and AGOM from the SGP4 model is used.

Type: Variable
Access: Read/Write

FPAngle

Returns the flight path angle, which is measured between the perpendicular of the instantaneous position and the instantaneous velocity vectors of the spacecraft.

Type: Variable
Access: ReadOnly
Units: deg

FPAzimuth

Returns the azimuth angle of the flight path, which is measured between the local North vector and the velocity vector.

Type: Variable
Access: ReadOnly
Units: deg

GNSSReceivers

The spacecraft's Globlal Navigation Satellite System (GNSS) receivers.

Type: Array of GNSSReceiver
Access: ReadOnly

Height

Returns the height of the Spacecraft above its central body, measured along a vector normal to the surface of the body at the Spacecraft's subsatellite point. The oblateness of the central body is taken into account when calculating the height. If Earth is set as the central body using the default radius and flattening coefficient, regardless of gravitational potential model, FreeFlyer will use the WGS 84 reference ellipsoid.

Type: Variable
Access: ReadOnly
Units: km

HistoryMode

Determines if the visualized Spacecraft tail is unlimited in length, or whether new points replace the oldest points once the tail exceeds the Spacecraft tail length. The history mode can be overridden for an individual view using ViewWindow.SetObjectHistoryMode() method.

Type: Variable
Access: Read/Write

HorizontalFPA

The horizontal flight path angle in the Spherical Lat/Long Element Set. It is measured from the velocity vector to the plane perpendicular to the position vector.

Type: Variable
Access: Read/Write
Units: deg

HyperbolicExcessVelocity

Returns the hyperbolic excess velocity of the calling Spacecraft at its current semimajor axis. This property is defined for hyperbolic orbits, and will return undefined for trajectories which have a semimajor axis greater than 0.

Type: Variable
Access: ReadOnly
Units: km/s

I

The Keplerian inclination (i). The angle between the orbit plane and the fundamental plane of the ICRF.

Type: Variable
Access: Read/Write
Units: deg

IsUsingAHF

Boolean value indicating whether or not the attitude motion model is based on an AHF.

Type: Variable
Access: ReadOnly

KSCEarthSunAngles

Returns a fiveelement Array containing the KSC EarthSun angles. These angles can be accessed individually using the AlphaTS, AlphaRS, AlphaTE, AlphaRE, and LVBeta properties.

Type: Array
Access: ReadOnly
Units: deg

Latitude

The Latitude property is the bodydetic latitude of the Spacecraft subsatellite point in the Spherical Lat/Long Element Set. It is defined as the angle between the fundamental plane of the BodyFixed coordinate system of the central body and the vector normal to the central body's surface passing through the satellite's position. This property returns a scalar value.

Type: Variable
Access: Read/Write
Units: deg

LatLongAzimuth

The velocity azimuth angle in the Spherical Lat/Long Element set. It is defined as the angle, measured eastward in the plane perpendicular to the position vector, from the projection of the central body's inertial coordinate frame's zaxis onto this plane to the projection of the velocity vector onto this plane.

Type: Variable
Access: Read/Write
Units: deg

LatLongRadius

The magnitude of the position vector in the Spherical Lat/Long Element set.

Type: Variable
Access: Read/Write
Units: km

LatLongVi

The magnitude of the velocity vector in the inertial frame in the Spherical Lat/Long Element set.

Type: Variable
Access: Read/Write
Units: km/s

LCSEpoch

The reference epoch associated with the Launch Coordinate reference frame. This is usually set at the time of liftoff. The format can be either in days or a calendar format, depending on the LCSEpochCoordSys.

Type: TimeSpan
Access: Read/Write
Units: day

LCSLatitude

The latitude of the launch site for the Launch Coordinate System. The LCSLatitude is for reference only and has no effect on conversion to the Launch Coordinate System.

Type: Variable
Access: Read/Write
Units: deg

LCSLongitude

The LCSLongitude is the associated reference longitude and is usually set at the longitude of the launch site. The Launch Coordinate System was designed to facilitate analysis of satellite launches. Launch coordinates have advantages such that the right ascension of the ascending node may be specified independently from the launch time and date. Launch Coordinate System Definition is as follows:
Origin  center of the Earth.
Zaxis  northpointing vector normal to the true equatorial plane at the reference epoch.
Xaxis  lies in the true equatorial plane at the reference epoch, and points from the center of the Earth to the reference longitude on the Earth's surface.
Yaxis  forms a righthanded coordinate system.

Type: Variable
Access: Read/Write
Units: deg

Lift

Represents the instantaneous force on the Spacecraft due to atmospheric lift modeling.

Type: Array
Access: ReadOnly
Units: N

LiftArea

The Lift Area is the incident cross sectional area to the velocity direction. It is used in the calculation of the force on the spacecraft due to atmospheric Lift.

Type: Variable
Access: Read/Write
Units: m^2

LongAscendingNode

Returns the geographic East longitude of the subsatellite point at the ascending node, when the Spacecraft crosses the equator from south to north. This method will return a null data value (999) until the first nodal crossing.

Type: Variable
Access: ReadOnly
Units: deg

LongDescendingNode

Returns the geographic East longitude of the subsatellite point at the descending node, when the Spacecraft crosses the equator from north to south. This method will return a null data value (999) until the first nodal crossing.

Type: Variable
Access: ReadOnly
Units: deg

Longitude

The Longitude property is the longitude of the Spacecraft subsatellite point in the Spherical Lat/Long Element set. It is defined as the angle between the prime meridian and the projection of the position vector onto the fundamental plane of the BodyFixed coordinate system of the central body. It is measured as increasing in a counterclockwise sense when viewed from the North Pole, thus producing the longitude east from the prime meridian. This property returns a scalar value.

Type: Variable
Access: Read/Write
Units: deg

LongitudeOfPeriapsis

Returns the angle measured between the vernal equinox and periapsis.

Type: Variable
Access: ReadOnly
Units: deg

LongitudeRate

Calculates the rate of change in longitude of the orbital plane in a BodyFixed frame of reference. Computes the difference between the Spacecraft orbital period and the CentralBody's rotational period, and then maps the result to degrees of longitudinal drift per second. Typically this property is used to examine the rate of drift within a GEO stationkeeping box. Note that this property is only supported for builtin CelestialObjects.

Type: Variable
Access: ReadOnly
Units: deg/s

LunarBetaAngle

Returns the declination of the EarthMoon vector with respect to the EarthSun ecliptic plane.

Type: Variable
Access: ReadOnly
Units: deg

LVBeta

Returns the angle measured between the orbit angular momentum vector and the sunspacecraft line.

Type: Variable
Access: ReadOnly
Units: deg

MA

Represents the instantaneous Mean Anomaly of the Spacecraft.

Type: Variable
Access: ReadOnly
Units: deg

Mass

Returns the total mass of the Spacecraft, including all attached Tanks.

Type: Variable
Access: ReadOnly
Units: kg

MassFlowRate

The rate at which the mass of the Spacecraft is currently being depleted. This value will be nonzero only when the Spacecraft is maneuvering.

Type: Variable
Access: ReadOnly
Units: kg/s

MassTotal

The total mass of the Spacecraft including all attached Tanks.
If you set this property, VehicleDryMass is set to (MassTotal  total hardware mass).

Type: Variable
Access: Read/Write
Units: kg

MeanMotion

Returns the mean motion, which is a measure of how fast a spacecraft progresses through its elliptical orbit.

Type: Variable
Access: ReadOnly
Units: rad/s

MES

Returns the Moon  Earth  Sun angle. The angle has the vertex as the center of the Earth with rays to the center of the Moon and the center of the Sun.

Type: Variable
Access: ReadOnly
Units: deg

MEV

Returns the Moon  Earth  Vehicle angle. The angle has the center of the Earth as the vertex with rays to the center of the Moon and Spacecraft position.

Type: Variable
Access: ReadOnly
Units: deg

MGL

Returns the sum of the Mean Anomaly and the longitude of periapsis minus the Spacecraft.CentralBodyObject's prime meridian apparent sidereal time (see the CelestialObject.GetPrimeMeridianApparentSiderealTime for more information).

Type: Variable
Access: ReadOnly
Units: deg

Mlt

Returns the Mean Local Time of the Spacecraft's subsatellite point, which is the current UTC time of the Spacecraft's epoch adjusted by accounting for the Spacecraft's longitude.

Type: Variable
Access: ReadOnly
Units: hr

MltAscendingNode

Returns the Mean Local time (MLT) of the Spacecraft's subsatellite point at each Ascending Node crossing. This method will return a null data value (999) until the Spacecraft crosses an ascending node. See the help file for a description on how FreeFlyer calculates the MLTAN.

Type: Variable
Access: ReadOnly
Units: hr

MltDescendingNode

Returns the Mean Local time (MLT) of the Spacecraft's subsatellite point at each Descending Node crossing. This method will return a null data value (999) until the Spacecraft crosses a descending node. See the help file for a description on how FreeFlyer calculates the MLTDN.

Type: Variable
Access: ReadOnly
Units: hr

ModifiedEquinoctialF

The f component of the Modified Equinoctial element set, defined by: f = e*cos(w + RAAN) where e, w, and RAAN are the Keplerian Eccentricity, Argument of Perigee and Right Ascension of the Ascending Node respectively. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

ModifiedEquinoctialG

The g component of the Modified Equinoctial element set, defined by: g = e*sin(w + RAAN) where e, w, and RAAN are the Keplerian Eccentricity, Argument of Perigee and Right Ascension of the Ascending Node respectively. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

ModifiedEquinoctialH

The h component of the Modified Equinoctial element set, defined by: h = tan(i/2)*cos(RAAN) where i is the orbit inclination and RAAN is the Keplerian Right Ascension of the Ascending Node. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

ModifiedEquinoctialK

The k component of the Modified Equinoctial element set, defined by: k = tan(I/2)*sin(RAAN) where i is the orbit inclination and RAAN is the Keplerian Right Ascension of the Ascending Node. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

ModifiedEquinoctialL

The True Longitude, L, is defined by: L = RAAN + w + TA, where RAAN and w are the Right Ascension of the Ascending Node and the Argument of Perigee, respectively, and TA is the Keplerian true anomaly. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write
Units: deg

ModifiedEquinoctialP

The semiparameter p is defined by: p = a*(1e^2) where a and e are the Keplerian SemiMajor Axis and Eccentricity.

Type: Variable
Access: Read/Write
Units: km

MOI

Returns the components of the moment of inertia matrix of the dry Spacecraft and all attached Tanks. The Spacecraft's moment of inertia is updated during maneuvers as fuel is depleted from the tanks. The MOI is also used as an input with the Spinner attitude system.

Type: Matrix
Access: ReadOnly
Units: kg m^2

MonthOfYear

Returns a numerical value (integer) representing the current month of the year. The month is given as an integer number ranging from 1 to 12, where 1 corresponds to January.

Type: Variable
Access: ReadOnly

MoonBAngle

Returns the angle, in the moon Bplane, of the piercing point measured from the T vector.

Type: Variable
Access: ReadOnly
Units: deg

MoonBDotR

Returns the projection of the piercing point in the moon Bplane onto the R vector.

Type: Variable
Access: ReadOnly
Units: km

MoonBDotT

Returns the projection of the piercing point in the moon Bplane onto the T vector.

Type: Variable
Access: ReadOnly
Units: km

MoonBMagnitude

Returns the distance of the piercing point from the origin of the moon Bplane. In terms of the Cartesian coordinates.
MoonBMagnitude = SQRT(MoonBdotT^2 + MoonBdotR^2)

Type: Variable
Access: ReadOnly
Units: km

MoonVelocity

Returns a three dimensional vector representing the velocity of the moon in the ICRF.

Type: Array
Access: ReadOnly
Units: km/s

MVE

Returns the Moon  Vehicle  Earth angle. The angle has the vertex as the Spacecraft position with rays to the center of the Moon and to the center of the Earth.

Type: Variable
Access: ReadOnly
Units: deg

NodeRate

Returns an estimate of the rate of change of the ascending node with respect to time. This estimate is based on the Gauss VOP equation, where:
J2= geopotential coefficient for the oblateness of the Earth
n = mean motion of the Spacecraft
Re= equatorial radius of the Earth
a = Spacecraft's osculating semimajor axis
e = Spacecraft's osculating eccentricity
i = Spacecraft's osculating inclination

Type: Variable
Access: ReadOnly
Units: deg/day

NonSingularA

The semimajor axis (a) property for the NonSingular Keplerian element set. Half the length of the long axis of the orbit ellipse.

Type: Variable
Access: Read/Write
Units: km

NonSingularE1

The e1 component of the Nonsingular Keplerian element set, defined by e1 = e*cos(RAAN + w), where e, w, and RAAN are the Keplerian Eccentricity, Argument of Perigee and Right Ascension of the Ascending Node respectively. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

NonSingularE2

The e2 component of the Nonsingular Keplerian element set, defined by e2 = e*sin(RAAN + w), where e, w, and RAAN are the Keplerian Eccentricity, Argument of Perigee and Right Ascension of the Ascending Node respectively. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

NonSingularE3

The e3 component of the NonSingular Keplerian element set, defined by: e3 = sin(i/2) sin(RAAN), where i is the orbit inclination and RAAN is the Keplerian Right Ascension of the Ascending Node. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

NonSingularE4

The e4 component of the NonSingular Keplerian element set, defined by: e4 = sin(i/2) cos(RAAN), where i is the orbit inclination and RAAN is the Keplerian Right Ascension of the Ascending Node. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write

NonSingularE5

The e5 component of the NonSingular Keplerian element set, defined by: e5 = RAAN + w + MA, where RAAN is the Right Ascension of the Ascending Node, w is the Right Ascension of the Ascending Node, and MA is the Mean Anomaly. These orbit properties are with respect to the ICRF.

Type: Variable
Access: Read/Write
Units: deg

NutationAngle

The nutation angle of a spinning Spacecraft is the coelevation of a spinning Spacecraft's spin axis with respect the zaxis of the angular momentum frame.

Type: Variable
Access: Read/Write
Units: deg

ObjectId

The unique identifier for the object.

Type: Variable
Access: ReadOnly

ObjectType

The type of the object.

Type: String
Access: ReadOnly

OD

This property contains the OD settings for all the Spacecraft properties that can be estimated.

Type: SpacecraftODProperties
Access: ReadOnly

OrbitalAngularAcceleration

Represents the instantaneous orbital angular acceleration about the central body referenced in the ICRF.

Type: Array
Access: ReadOnly
Units: rad/s^2

OrbitalAngularMomentum

Represents the instantaneous specific orbital angular momentum (angular momentum per unit mass) vector about the central body referenced in the ICRF.

Type: Array
Access: ReadOnly
Units: km^2/s

OrbitalAngularVelocity

Represents the instantaneous orbital angular velocity vector about the central body referenced in the ICRF.

Type: Array
Access: ReadOnly
Units: rad/s

OrbitNormal

Represents the instantaneous orbit normal vector about the central body referenced in the ICRF.

Type: Array
Access: ReadOnly

OrbitNumberBounded

Returns the number of times a Spacecraft has orbited the central body (revolutions). It is incremented each time the Spacecraft crosses the ascending node, and decremented similarly for backwards propagation. This property resets to orbit 1 the orbit after the orbit number reaches Spacecraft.OrbitNumberResetNumber. Note, you must enable orbit number calculations before propagating this Spacecraft by setting Spacecraft.OrbitNumberCalculationEnabled = 1.

Type: Variable
Access: Read/Write

OrbitNumberCalculationsEnabled

This property enables calculations that are required in order to compute the Spacecraft's orbit number. Enable this property at the beginning of your propagation if you plan to report the Spacecraft's orbit number in this Mission Plan. If this property is disabled, an error will be reported if any of the Spacecraft's orbit number properties are accessed. Orbit number calculations incur an overhead for every propagation step, and therefore should be disabled unless needed.

Type: Variable
Access: Read/Write

OrbitNumberCumulative

Returns the number of times a Spacecraft has orbited the central body (revolutions). It is incremented each time the Spacecraft crosses the ascending node, and decremented similarly for backwards propagation. Note, you must enable orbit number calculations before propagating this Spacecraft by setting Spacecraft.OrbitNumberCalculationEnabled = 1.

Type: Variable
Access: Read/Write

OrbitNumberDaily

Returns the number of times a Spacecraft has orbited the central body (revolutions) and resets to orbit 1 for the first ascending node that crosses Spacecraft.OrbitNumberResetLongitude degrees East longitude. It is incremented each time the spacecraft crosses the ascending node, and decremented similarly for backwards propagation. Note, you must enable orbit number calculations before propagating this Spacecraft by setting Spacecraft.OrbitNumberCalculationEnabled = 1.

Type: Variable
Access: Read/Write

OrbitNumberResetLongitude

The Spacecraft.OrbitNumberDaily property will reset to 1 if the Spacecraft's longitude of the ascending node crosses this boundary in either direction (i.e. from East to West or from West to East). If the OrbitNumberResetLongitude is changed, the RefreshDailyOrbitNumber() method must be called before the OrbitNumberDaily property will update. Note, you must enable orbit number calculations before propagating this Spacecraft by setting Spacecraft.OrbitNumberCalculationEnabled = 1.

Type: Variable
Access: Read/Write

OrbitNumberResetNumber

The orbit number value after which Spacecraft.OrbitNumberBounded will reset back to 1. If set to 0, the bounded orbit number will never reset back to 1. If set to something other than 0 and the bounded orbit number is outside of bounds, the OrbitNumberBounded property will be reset back 1. Note, you must enable orbit number calculations before propagating this Spacecraft by setting Spacecraft.OrbitNumberCalculationEnabled = 1.

Type: Variable
Access: Read/Write

P

Represents the osculating value of the semilatus rectum of the Spacecraft's orbit. The value of the semilatus rectum is equal to the square of the specific angular momentum of the orbit (angular momentum per unit mass) divided by the central body's gravity constant m.

Type: Variable
Access: ReadOnly
Units: km

PercentEarthShadow

Returns a numerical value representing the percentageofshadow the Spacecraft encounters in its orbit with respect to Earth's shadow. The calculation is based on percentage of shadow the Spacecraft encounters during penetration into the penumbral region. Once into the umbral region the percentage of shadow is 100%.

Type: Variable
Access: ReadOnly

PercentMoonShadow

Returns a numerical value representing the percentageofshadow the Spacecraft encounters in its orbit with respect to the Moon's shadow. The calculation is based on percentage of shadow the Spacecraft encounters during penetration into the penumbral region. Once into the umbral region the percentage of shadow is 100%.

Type: Variable
Access: ReadOnly

Periapsis

Returns an instantaneous osculating estimate of the periapsis distance from the center of the CentralBody to the Spacecraft, based on the current orbital state. The Spacecraft.Periapsis property is not based on a force model and is computed directly from the instantaneous Keplerian elements where the instantaneous Keplerian elements are computed from the active state of the Spacecraft.

Type: Variable
Access: ReadOnly
Units: km

Perigee

Returns an instantaneous osculating estimate of the periapsis distance from the center of its central body to the Spacecraft, based on the current orbital state. The Spacecraft.Perigee property is not based on a force model and is computed directly from the instantaneous Keplerian elements where the instantaneous Keplerian elements are computed from the active state of the Spacecraft.

Type: Variable
Access: ReadOnly
Units: km

PerigeeHeight

Returns the instantaneous osculating periapsis height of the Spacecraft above its central body, measured along a vector normal to the surface of the body at the Spacecraft's subsatellite point. The oblateness of the central body is taken into account when calculating the height.

Type: Variable
Access: ReadOnly
Units: km

Period

Returns the osculating period, which corresponds to the instantaneous unperturbed twobody Keplerian orbit.

Type: Variable
Access: ReadOnly
Units: min

Pitch

Returns the angle about the yaxis of the 312 Euler sequence that represents the orientation of the Spacecraft Body Coordinate System from its reference attitude frame.

Type: Variable
Access: ReadOnly
Units: deg

PlateModel

The child object which contains all of the properties and methods associated with the Spacecraft's PlateModel. The PlateModel can be used to model higherfidelity solar radiation pressure (SRP).

Type: PlateModel
Access: ReadOnly

Position

Returns the Spacecraft's X, Y, Z position referenced to the ICRF.

Type: Array
Access: Read/Write
Units: km

Propagator

The propagator for updating the orbital state of the Spacecraft.

Type: Propagator
Access: ReadOnly

PropagatorType

The object type of the propagator that is associated with the Spacecraft.

Type: String
Access: ReadOnly

ProximityZones

The Spacecraft's proximity zones.

Type: Array of ProximityZone
Access: ReadOnly

Quaternion

Returns the four components of the attitude quaternion of a Spacecraft. The first three components represent the vector part of the quaternion, the last component represents the scalar part. FreeFlyer uses the righthanded convention when applying the quaternion rotation.

Type: Array
Access: Read/Write

RA

The right ascension of the satellite in the Spherical Element Set. This is the angle from the xaxis of the ICRF to the projection of the satellite position vector onto the fundamental plane of the coordinate frame.

Type: Variable
Access: Read/Write
Units: deg

RAAN

The Keplerian right ascension of the ascending node (RAAN). The angle, measured at the center of the central body, from the vernal equinox to the ascending node. The ascending node is the point where the satellite crosses the fundamental plane of the ICRF going from south to north.

Type: Variable
Access: Read/Write
Units: deg

RADescendingNode

Represents the osculating Right Ascension of the Descending Node (RADN) in the ICRF. The RADN is defined as the angle, measured at the center of the central body, from the vernal equinox to the Descending Node.

Type: Variable
Access: ReadOnly
Units: deg

Radius

The magnitude of the Cartesian position vector of the Spacecraft with respect to the central body.

Type: Variable
Access: ReadOnly
Units: km

Roll

Returns the angle about the xaxis of the 312 Euler sequence that represents the orientation of the Spacecraft Body Coordinate System from its reference attitude frame.

Type: Variable
Access: ReadOnly
Units: deg

SatelliteId

Used by orbit determination algorithms to identify the Spacecraft.

Type: String
Access: Read/Write

Sensors

The Spacecraft's sensors.

Type: Array of Sensor
Access: ReadOnly

SEV

Returns the Sun  Earth  Vehicle angle. The angle has the vertex as the center of the Earth with rays to the Sun center and Spacecraft position.

Type: Variable
Access: ReadOnly
Units: deg

SGP4

Object holding options for managing the SGP4 propagation model and orbital element set.

Type: SGP4Properties
Access: ReadOnly

SolarFlux

Returns the instantaneous value of the Solar Flux at the spacecraft, measured in W/m^2. The SolarFlux property is not associated with the environmental information of any drag model, and is not the same as the F10.7 cm solar flux that is used in some atmospheric density models.

Type: Variable
Access: ReadOnly

SphericalAzimuth

The velocity azimuth angle in the Spherical Element Set. The angle, measured eastward in the plane perpendicular to the position vector, from the projection of the ICRF's zaxis onto this plane to the projection of the velocity vector onto this plane.

Type: Variable
Access: Read/Write
Units: deg

SphericalRadius

The magnitude of the position vector in the Spherical Element set.

Type: Variable
Access: Read/Write
Units: km

SpinPhase

Phase angle of the xaxis of the Body Coordinate System with respect to the projection of the xaxis of the ICRF into the spin plane. If SpinPhase = 0, the initial xaxis of the Body Coordinate System will be coincident with the projection of the xaxis of the ICRF into the spin plane.

Type: Variable
Access: Read/Write
Units: deg

SpinRate

The angular rotation rate of a spinning Spacecraft about its spin axis, i.e, the zaxis of the "spin frame".

Type: Variable
Access: Read/Write
Units: deg/s

SRPArea

The SRP Area is the incident cross sectional area to the SunEarth line. It is used in the calculation of the force on the spacecraft due to solar radiation pressure.
If the Spacecraft's ForceModel.SRPForceGeometry is set to use a PlateModel, then this property will reflect the incident SRP area of the PlateModel, and an error will be reported if you try to assign a value to this property.

Type: Variable
Access: Read/Write
Units: m^2

SunVelocity

Returns a threedimensional vector representing the velocity of the Sun in the ICRF.

Type: Array
Access: ReadOnly
Units: km/s

SVE

Returns the Sun  Vehicle  Earth angle. The angle has the vertex as the Spacecraft position with rays to the center of the Sun and to the center of the Earth.

Type: Variable
Access: ReadOnly
Units: deg

SVM

Returns the Sun  Vehicle  Moon angle. The angle has the vertex as the Spacecraft position with rays to the center of the Sun and to the center of the Moon.

Type: Variable
Access: ReadOnly
Units: deg

TA

The Keplerian true anomaly. The angle measured at the center of the central body, from perigee to the current position of the satellite.

Type: Variable
Access: Read/Write
Units: deg

TailLength

The number of historical position points to save and draw in visualizations generated using the View command. A new point will be added each time the View command is called. If you use a ViewWindow object, the tail length set there will override this tail length.
In millisecond timing precision mode only, the deprecated "as Global" syntax can be used to update the View when any Vehicle is Stepped or Maneuvered.
Use caution in setting tail lengths longer than 10,000  30,000 points. Tail lengths exceeding this range can cause memory problems due to the large amount of relative position data that must be maintained. The maximum tail length that can be used safely depends on the amount of memory in the system and the number of objects managed by the Mission View.

Type: Variable
Access: Read/Write

Tanks

The spacecraft's fuel tanks.

Type: Array of Tank
Access: ReadOnly

ThreeDModelFile

The file name of the file containing the 3D model that will represent the Spacecraft in a Mission View.

Type: String
Access: Read/Write

ThreeDModelObject

The name of the ThreeDModel object that holds information about the physical geometry of the Spacecraft.

Type: ThreeDModel
Access: ReadOnly

Thrusters

The spacecraft's thrusters.

Type: Array of Thruster
Access: ReadOnly

TickType

The tick mark shape to draw at each point of the tail in a Mission View.

Type: String
Access: Read/Write

TimeOfDay

Returns the current Spacecraft time referenced to Greenwich Mean Time (GMT or UTC).

Type: TimeSpan
Access: ReadOnly
Units: hr

TotalElectronContent

Returns the Total Vertical Electron Content for a 1 m^2 column that extends radially through the entire Ionosphere. The location of the column is based on the Geodetic Latitude and Longitude of the Spacecraft. The Total Electron Content is calculated using the Ionosphere model type and properties specified in the Ionosphere Options within the Solar System.

Type: Variable
Access: ReadOnly
Units: 1/m^2

Transponders

The spacecraft's transponders.

Type: Array of Transponder
Access: ReadOnly

TrueLongitude

Returns the value of the angle measured from the vernal equinox to the spacecraft's current position with the center of the central body as its vertex.

Type: Variable
Access: ReadOnly
Units: deg

VehicleDryCenterOfGravity

The vector representing the dry vehicle center of mass (i.e. no attached Tanks are included in this property) referenced from the origin of the Spacecraft's body fixed frame.. This property is used in calculating the CenterOfMass, which includes all attached Tanks in its calculation.

Type: Array
Access: Read/Write
Units: m

VehicleDryMass

The Spacecraft's dry vehicle mass. The fuel mass is input through the tank and updated as mass is depleted.

Type: Variable
Access: Read/Write
Units: kg

VehicleDryMOI

The dry vehicle moment of inertia matrix (i.e. no attached Tanks are included in this property). This property is used in calculating the Spacecraft MomentOfInertia, which includes all attached Tanks in its calculation. The MOI is referenced from the origin of the Spacecraft BCS.

Type: Matrix
Access: Read/Write
Units: kg m^2

Velocity

Returns the instantaneous Spacecraft velocity vector in Cartesian components (VX, VY, VZ) referenced to the ICRF.

Type: Array
Access: Read/Write
Units: km/s

VerticalFPA

The vertical flight path angle in the Spherical Element set. The angle between the position and velocity vectors of the satellite.

Type: Variable
Access: Read/Write
Units: deg

Vi

The magnitude of the velocity vector in the inertial frame in the Spherical Element set.

Type: Variable
Access: Read/Write
Units: km/s

VMag

Represents the instantaneous magnitude of the Spacecraft's velocity.

Type: Variable
Access: ReadOnly
Units: km/s

VX

The Cartesian Xcomponent of the Spacecraft's velocity vector, referenced to the ICRF.

Type: Variable
Access: Read/Write
Units: km/s

VY

The Cartesian Ycomponent of the Spacecraft's velocity vector, referenced to the ICRF.

Type: Variable
Access: Read/Write
Units: km/s

VZ

The Cartesian Zcomponent of the Spacecraft's velocity vector, referenced to the ICRF.

Type: Variable
Access: Read/Write
Units: km/s

W

The Keplerian argument of perigee (w). The angle measured at the center of the central body, from the ascending node to the point in the satellite's orbit closest to the central body.

Type: Variable
Access: Read/Write
Units: deg

WeekOfMonth

Returns a numerical value representing the current week of the month. The week is given as an integer number ranging from 1 to 5, where 1 is equivalent to the first week of the month.

Type: Variable
Access: ReadOnly

X

The Cartesian Xcomponent of the Spacecraft's position vector, referenced to the ICRF.

Type: Variable
Access: Read/Write
Units: km

Y

The Cartesian Ycomponent of the Spacecraft's position vector, referenced to the ICRF.

Type: Variable
Access: Read/Write
Units: km

Yaw

Returns the angle about the zaxis of the 312 Euler sequence that represents the orientation of the Spacecraft Body Coordinate System from its reference attitude frame.

Type: Variable
Access: ReadOnly
Units: deg

Year

Returns the current fourdigit year.

Type: Variable
Access: ReadOnly

Z

The Cartesian Zcomponent of the Spacecraft's position vector, referenced to the ICRF.

Type: Variable
Access: Read/Write
Units: km
