Available Objects

Name

Description

Available In

AccelerationTerm

The AccelerationTerm object is used to provide insight into the accelerations due to various forces on a Spacecraft. This object is not creatable in script, but an Array of AccelerationTerm objects is always available as a property of the Spacecraft object, as seen in the example below:

Report Spacecraft1.Accelerations[i].Description, Spacecraft1.Accelerations[i].Acceleration;

Engineer

Mission

AcqData

The AcqData object is used when creating Improved Inter-Range Vector (IIRV) and Extended Precision Vector (EPV) messages using the Spacecraft.IIRV(AcqData1) or Spacecraft.EPV(AcqData1) methods.  The AcqData object contains various information used to build this string message, including the type of vector and the reference coordinate system, which is combined with the Spacecraft state vector (position and velocity) at a given epoch, as well as additional spacecraft properties.  The IIRV and EPV formats are specified by the “Tracking and Acquisition Handbook for the Spaceflight Tracking and Data Network”, October 1994.

To report the IIRV or EPV to an output file, the “as Binary” and “without linefeed” options should be used, in order to ensure properly formatted line endings.  For example:

Report as Binary Spacecraft1.IIRV(AcqData1) to "myIIRV.txt" without linefeed;

Engineer w/NasaPack

Mission w/NasaPack

Array

The Array object contains a one-dimensional set of numbers. An Array with N elements is indexed by n = 0,1,2...N-1. The number of elements in an Array can be set when the Array is created using square brackets. The length of the Array can be changed after the Array is first created. Array elements are accessed using square brackets. See the Matrix, Array, and Variable Math Script Reference for more information. This example shows how to create an array with three elements and assign the first element a value of five:

Array Array1[3];

Array1[0] = 5;

This example shows how to create an Array and make it a 4-element array containing the values 2, 4, 6, 8:

Array Array2;

Array2 = {2, 4, 6, 8};

You can assign Array objects using the = operator.

Note: In millisecond mode, if the number of elements is not specified, the Array will have ten elements.

Engineer

Mission

BatchLeastSquaresOD

The BatchLeastSquaresOD object provides algorithms for performing Orbit Determination and State Estimation using a weighted-least squares technique, processing an entire "batch" of observations all at one time.  All observations are processed to perform one State Update at the user-specified Solution Epoch.  See the Orbit Determination Guide for more information.

Mission

BlackJackPointSolutionFile

The BlackJackPointSolutionFile object provides functionalities to both read and write BlackJack Point Solution files.  This is an ASCII file of Point Solution data as put out by the BlackJack GPS receiver.  The time system is GPS Time, and the position and velocity values are given in units of km and km/s in the Earth Fixed reference frame.  

Mission

BlockageDiagram

The BlockageDiagram object uses a bitmap to create a representation of blockage due to a combination of 3D CAD model configuration and custom angular regions when viewed from a given viewpoint on a Spacecraft.

Engineer

Mission

BlockageViewpointOptions

The BlockageViewpointOptions object allows the user to configure a blockage diagram type Viewpoint object. This object is not creatable in script, but is always created as a child object of the Viewpoint object as seen in the example below:

Viewpoint1.BlockageView.LookAngle1Center = 0;

Engineer

Mission

BroadcastEphemeris

The BroadcastEphemeris object provides a FreeFlyer propagator type that makes use of a RINEX Navigation file (broadcast ephemeris) as the motion model.

Engineer

Mission

BRTSLink

The BRTSLink object is an internal object used to define links from originating GroundStation objects to the remote ground terminal for use in processing BRTSObservation data. This object is not creatable in script, but an Array of BRTSLink objects is always available as a property of the BRTSUTDFFile object, as seen in the example below:

Report BRTSUTDFFile1.BRTSLinks[0].Observer;

Mission

BRTSObservation

The BRTSObservation object holds Measurements associated with the Bilateration Ranging Transponder System (BRTS). This is a system where a ranging signal is transmitted from a Ground Station, relayed through a TDRS Spacecraft to a remote Ground Station, where a Transponder coherently turns the signal around. This signal is then relayed all the way back to the originating Ground Station. The Measurements for a BRTSObservation can include TwoWayRange and TwoWayDoppler.

Mission

BRTSObservationMeasurements

The BRTSObservationMeasurements object is a container for all measurement noise and bias information related to the BRTSObservation. The BRTSObservationMeasurements object holds the data associated with the RemoteTransponderDelay Estimable Bias and the noise and bias data for the TwoWayRange and TwoWayDoppler Measurement objects. This object is not creatable in script, but is always created as a child object of the GroundAntennaODProperties object as seen in the example below:

GroundStation1.Antenna.OD.BRTSObservation.TwoWayDoppler.Noise = 2;

Engineer

Mission

BRTSUTDFFile

The BRTSUTDFFile object provides functionalities for reading Bilateration Ranging Transponder System (BRTS) Observation data (two-way Doppler and two-way range) from binary files written in the 75-byte binary Universal Tracking Data Format (UTDF). The time system for data contained in the BRTSUDTFFile is UTC, TwoWayRange data are given in km, and TwoWayDoppler data are given in Hz.

Mission

BulStoer

The Bulirsch Stoer propagator is a self-starting single step method that is designed to take very large steps compared to the Runge-Kutta propagators at comparable accuracy. See expanded description.

Engineer

Mission

BulStoerVOP

Bulirsch Stoer VOP solves the Encke formulation of the orbit equations of motion in equinoctial coordinates using the Bulirsch Stoer integrator. The Bulirsch Stoer VOP propagator is based on a Variation of Parameters (VOP) formulation of the equations of motion. See expanded description.

Engineer

Mission

Burn

The Burn object is a base type that provides attitude, maneuver, scale factor, and burn component properties to the objects that derive from it. See the Maneuvering Guide for more information.

Engineer

Mission

CartesianOrbitStateEstimablePropertyContainer

The CartesianOrbitStateEstimablePropertyContainer object provides a collection of the Cartesian estimable properties for use when estimating the Spacecraft state in the Cartesian element set. This object is not creatable in script, but is always created as a child object of the SpacecraftODProperties object, as seen below:

Spacecraft1.OD.Cartesian.X.Sigma = 0.05;

Engineer

Mission

CartesianStateObservation

The CartesianStateObservation object contains an observation (or measurement) in the Cartesian state.

Mission

CCSDSOEMProperties

The CCSDSOEMProperties object provides a collection of properties associated with reading and writing the header of CCSDS OEM ephemeris files. This object is not creatable in script, but is always created as a child object of the Ephemeris object, as seen in the example below:

myEphemeris.CCSDSOEMProperties.ReferenceFrame = "EME2000";

Engineer

Mission

CCSDSOEMValidationOptions

The CCSDSOEMValidationOptions object provides a collection of properties associated with how certain validation mechanisms behave for reading in CCSDS OEM files. This object is not creatable in script, but is always created as a child object of the CCSDSOEMProperties object, as seen in the example below:

myEphemeris.CCSDSOEMProperties.ValidationOptions.EnforceMetadataStartStopTimeDataSpanConsistency = 0;

Engineer

Mission

CelestialObject

The CelestialObject makes it possible to model custom physical objects (ie, a planet, moon, asteroid, or comet). A CelestialObject's movement can be specified using SPICE Files. Any CelestialObject can be used as a force and be applied to any Spacecraft. See Celestial Objects for more information.

Engineer

Mission

CelestialSphereViewpointOptions

The CelestialSphereViewpointOptions object allows the user to configure a celestial sphere type Viewpoint object. This object is not creatable in script, but is always created as a child object of the Viewpoint object as seen in the example below:

Viewpoint1.CelestialSphereView.Declination = 20;

Engineer

Mission

CelestialSystem

The CelestialSystem makes it possible to set up a collection of Celestial Objects. This provides access to positions and velocities of spacecraft and Celestial Objects relative to the entire system as well as visualization options for the custom system. CelestialSystems can be added to RotatingLibrationPoint objects as primary or secondary systems. See the Rotating Libration Point guide for more information.

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Mission

ChemicalTank

The ChemicalTank object is a base type that provides mixture ratio, fill line, density, temperature, pressure, and volume properties to the objects that derive from it.  See the Maneuvering Guide for more information.

Engineer

Mission

ColorUtilities

The ColorUtilities object allows you to easily specify and manipulate colors in FreeFlyer.  You can directly specify the name of the desired color as well as adjust color brightness, interpolate multiple colors, and convert colors to grayscale. See table of color names and values

Engineer

Mission

ConsoleWindow

The ConsoleWindow can be used to display data or describe the steps of a Mission Plan as it executes. The Console object is a global instance of this base type. Despite that the Console object is automatically declared in every instance, multiple ConsoleWindow objects can still be created and used in FreeFlyer.

Engineer

Mission

Constants

The Constants object type has a number of static properties and methods on it to make it easier to access standard mathematical and physical constants used in space-based mission design. This object is not creatable in script.

Engineer

Mission

CoordinateSystem

CoordinateSystems can be used to set the orientation of ThreeDModels, ProximityZones, Sensors, and Spacecraft objects. CoordinateSystem objects can be built using two vectors, a direction cosine matrix, Euler angles, quaternions, a chain of existing coordinate systems, or using the Body Coordinate System of Spacecraft, CelestialObject, or Sensor objects. See the Vectors and Coordinate Systems Guide for more information.

Engineer

Mission

CovarianceUtilities

The CovarianceUtilities Object allows a user to calculate a covariance based on a set of states, and calculate random states generated based on a covariance. See the Orbit Determination Guide for more information.

Engineer

Mission

Cowell

The Cowell propagator uses a 10th order Störmer-Cowell predictor with an Adams-Bashforth-Moulton corrector propagator. This propagator uses past integrated Spacecraft states to predict and then correct the next orbital state. See expanded description.

Engineer

Mission

CustomEstimableProperty

The CustomEstimableProperty object is a base type that provides process action, process noise rate, sigma, smoothed value, and state update properties to the objects that derive from it.  See the Orbit Determination Guide for more information.

Mission

CustomForce

The CustomForce object is the base type for custom forces that have been defined using the FreeFlyer Extensions SDK. A custom force Extension must be created, compiled, and registered before the CustomForce object can be used in a Mission Plan. See the FreeFlyer Extensions guide for more information.

Mission

CustomObservation

The CustomObservation object holds Measurements associated with user defined unique measurement models. All estimators support the processing of custom observations. To run orbit determination using custom observations, two separate parts of the measurement model must be computed by the user:

•Both the pre- and post-update computed values

•The measurement partial derivatives (not required for the unscented kalman filter)

Mission

CustomObservationMeasurements

The CustomObservationMeasurements object is a container for all measurement noise and bias information related to the CustomObservation.

Engineer

Mission

DataBase

The DataBase object enables connectivity to Database Management Systems (DBMS). The Open Database Connectivity (ODBC) application program interface (API) is used as the connection mechanism. User-supplied Structured Query Language (SQL) statements specify the DBMS actions to be performed. See the Databases Guide for more information.

Mission

DataTableWindow

A DataTableWindow displays the specified data to the screen in spreadsheet format.

Engineer

Mission

DebuggerLogWindow

The DebuggerLogWindow can be used to display data through the Report command when the Debugger has been launched. The DebuggerLog object is a global instance of this base type.

Engineer

Mission

Diagnostics

The Diagnostics object type has a number of static properties and methods on it to enable error messages captured by Try blocks to be diagnosed and have their details reported. This object is not creatable in script.

Engineer

Mission

DifferentialCorrector

A DifferentialCorrector object can be used to provide access to the status of a Targeting loop. See the Targeting Guide for more information.

Engineer

Mission

DSN60ByteObservationFile

The DSN60ByteObservationFile object provides functionality for reading DSN data (range and range rate) from DSN 60-Byte Observation files. This is a GSFC internal 60-byte binary format. Each file of DSN 60-byte tracking data contains one or more header records and an associated batch of data records accompanying each header record – the header record containing information necessary for the accurate conversion of the raw data contained in the data records. The time system is UTC, and the range and range-rate data is reference frame independent.

Mission

DSNObservation

The DSNObservation object holds Measurements associated with a Deep Space Network (DSN) GroundStation's observation of a Spacecraft at an instant in time.  The Measurements for a DSNObservation include an ambiguous range (MeasuredRange) and total phase count (PhaseCountParts) which are resolved in physical units to Range and Range Rate by default.

Mission

ElectricalTank

The ElectricalTank is used to model a mass and power source for an Electrical thruster. See Tanks for more information.

Engineer

Mission

Email

The Email object allows data local to FreeFlyer to be transmitted to an external user via email. Any combination of text and internal FreeFlyer data may be transmitted. See the Email Guide for more information.

This object has been Deprecated. The Email object is no longer supported.

Mission

Ephemeris

An ephemeris is made up of data records which contain both the state (orbit) and (optionally) the orientation (attitude) of a Spacecraft at specific epochs. See FreeFlyer Ephemeris File for more information.

Engineer

Mission

EphemerisVector

The EphemerisVector object enables a user to conveniently handle a row in an Ephemeris object and manipulate values in that row of varying types, including String objects, Variable objects, and TimeSpan objects. You can assign EphemerisVector objects using the = operator.

Engineer

Mission

EquinoctialOrbitStateEstimablePropertyContainer

The EquinoctialOrbitStateEstimablePropertyContainer object provides a collection of the Equinoctial estimable properties for use when estimating the Spacecraft state in the Equinoctial element set. This object is not creatable in script, but is always created as a child object of the SpacecraftODProperties object, as seen below:

Spacecraft1.OD.Equinoctial.Longitude.Sigma = 0.001;

Engineer

Mission

EquinoctialStateObservation

The EquinoctialStateObservation object contains an observation (or measurement) in the Equinoctial state.

Mission

EstimableAcceleration

The EstimableAcceleration object holds information about how acceleration bias elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable accelerations are always created as child objects of the SpacecraftODProperties object as seen in the example below:

Spacecraft1.OD.OtherAccelerationsX.Sigma = 1e-006;

Engineer

Mission

EstimableAGOM

The EstimableAGOM object holds information about how the AGOM (Area times Gamma Over Mass) property of an object's state is handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable elements are always created as child objects of the SpacecraftODProperties objects as seen in the example below:

Spacecraft1.OD.AGOM.Sigma = 0.05;

Engineer

Mission

EstimableAngleBias

The EstimableAngleBias object holds information about how angle bias elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable angle biases are always created as child objects of the MeasurementGroundAzimuth, MeasurementGroundElevation, MeasurementSpacecraftAzimuth, and MeasurementSpacecraftElevation objects as seen in the example below:

GroundStation1.Antenna.OD.GroundObservation.Azimuth.Bias.Sigma = 1e-006;

Engineer

Mission

EstimableBStar

The EstimableBStar object holds information about how the BStar element of an object's state is handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable elements are always created as child objects of the SpacecraftODProperties objects as seen in the example below:

Spacecraft1.OD.BStar.Sigma = 0.05;

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Mission

EstimableCoefficient

The EstimableCoefficient object holds information about how coefficients of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable coefficients are always created as child objects of the ImpulsiveBurnODProperties, FiniteBurnODProperties, OutgassingEventODProperties, and SpacecraftODProperties objects as seen in the example below:

Spacecraft1.OD.Cd.Sigma = 0.05;

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Mission

EstimableCustomBias

The EstimableCustomBias object holds information about how custom bias elements of an object's state are handled in the Orbit Determination / State Estimation process.

Engineer

Mission

EstimableDistanceBias

The EstimableDistanceBias object holds information about how distance bias elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable distance biases are always created as child objects of the MeasurementBRTSTwoWayRange, MeasurementGroundRange, MeasurementSpacecraftRange, and MeasurementTDRSTwoWayRange objects as seen in the example below:

GroundStation1.Antenna.OD.GroundObservation.Range.Bias.Sigma = 1e-006;

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Mission

EstimableDopplerBias

The EstimableDopplerBias object holds information about how doppler bias elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable doppler biases are always created as child objects of the MeasurementBRTSTwoWayDoppler, MeasurementTDRSOneWayDoppler, and MeasurementTDRSTwoWayDoppler objects as seen in the example below:

GroundStation1.Antenna.OD.BRTSObservation.TwoWayDoppler.Bias.Sigma = 1e-006;

Engineer

Mission

EstimableEquinoctialA

The EstimableEquinoctialA object holds information about how the semi-major axis (from the Equinoctial element set) of a Spacecraft state is handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but EstimableEquinoctialA is always created as a child object of the EquinoctialOrbitStateEstimablePropertyContainer object, as seen below:

Spacecraft1.OD.Equinoctial.A.Sigma = 0.05;

Engineer

Mission

EstimableEquinoctialLongitude

The EstimableEquinoctialLongitude object holds information about how the mean longitude (from the Equinoctial element set) of a Spacecraft state is handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but EstimableEquinoctialLongitude is always created as a child object of the EquinoctialOrbitStateEstimablePropertyContainer and Sgp4OrbitStateEstimablePropertyContainer objects, as seen below:

Spacecraft1.OD.Equinoctial.Longitude.Sigma = 0.001;

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Mission

EstimableHeightBias

The EstimableHeightBias object holds information about how height bias elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but an estimable height bias is always created as a child object of the GroundStationODProperties object as seen in the example below:

GroundStation1.OD.HeightBias.Sigma = 1e-006;

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Mission

EstimableLatLongBias

The EstimableLatLongBias object holds information about how latitude and longitude bias elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable lat/lon biases are always created as child objects of the GroundStationODProperties object as seen in the example below:

GroundStation1.OD.LatitudeBias.Sigma = 1e-006;

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Mission

EstimableMeanMotion

The EstimableMeanMotion object holds information about how the mean motion (from the NoradEquinoctial element set) of a Spacecraft state is handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but EstimableMeanMotion is always created as a child object of the Sgp4OrbitStateEstimablePropertyContainer object, as seen below:

Spacecraft1.OD.SGP4.MeanMotion.Sigma = 0.001;

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Mission

EstimablePosition

The EstimablePosition object holds information about how position elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable positions are always created as child objects of the CartesianOrbitStateEstimablePropertyContainer object as seen in the example below:

Spacecraft1.OD.Cartesian.X.Sigma = 0.05;

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Mission

EstimablePositionBias

The EstimablePositionBias object holds information about how position bias elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable position biases are always created as child objects of the MeasurementPointSolutionX, MeasurementPointSolutionY, and MeasurementPointSolutionZ objects as seen in the example below:

(Spacecraft1.Receivers[0] AsType GPSReceiver).OD.PointSolutionObservation.X.Bias.Sigma = 0.01;

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Mission

EstimablePositionComponent

The EstimablePositionComponent object holds information about how the h, k, p, and q components (from the Equinoctial element set) of a Spacecraft state is handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but EstimablePositionComponent's are always created as a child object of the EquinoctialOrbitStateEstimablePropertyContainer and NoradOrbitStateEstimablePropertyContainer objects, as seen below:

Spacecraft1.OD.Equinoctial.H.Sigma = 1e-5;

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EstimableProperty

The EstimableProperty object is a base type that provides process action, process noise rate, sigma, smoothed value, and state update properties to the objects that derive from it.  See the Orbit Determination Guide for more information.

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EstimablePseudoRangeClockDrift

The EstimablePseudoRangeClockDrift object holds information about how the clock drift element of a GPSReceiver state is handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but an estimable pseudorange clock drift is always created as a child object of the PseudorangeObservationMeasurements object as seen in the example below:

(Spacecraft1.Receivers[0] AsType GPSReceiver).OD.PseudorangeObservation.ClockDrift.Sigma = 1e-005;

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EstimablePseudoRangeReceiverBias

The EstimablePseudoRangeReceiverBias object holds information about how the measured range bias element of a GPSReceiver state is handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but an estimable pseudorange receiver bias is always created as a child object of the MeasurementPseudorangeC1, MeasurementPseudorangeC2, MeasurementPseudorangeP1, and MeasurementPseudorangeP2 objects as seen in the example below:

(Spacecraft1.Receivers[0] AsType GPSReceiver).OD.PseudorangeObservation.C1.Bias.Sigma = 0.001;

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EstimablePseudoRangeTimeBias

The EstimablePseudoRangeTimeBias object holds information about how the time bias element of a GPSReceiver state is handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but an estimable pseudorange time bias is always created as a child object of the PseudorangeObservationMeasurements object as seen in the example below:

(Spacecraft1.Receivers[0] AsType GPSReceiver).OD.PseudorangeObservation.ClockBias.Sigma = 0.1;

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EstimableRangeRateBias

The EstimableRangeRateBias object holds information about how range rate bias elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable range rate biases are always created as child objects of the MeasurementGroundRangeRate and MeasurementSpacecraftRangeRate objects as seen in the example below:

GroundStation1.Antenna.OD.GroundObservation.RangeRate.Bias.Sigma = 1e-006;

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EstimableTimeBias

The EstimableTimeBias object holds information about how time bias elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable time biases are always created as child objects of the BRTSObservationMeasurements, GroundAntennaODProperties, OutgassingEventODProperties, PointSolutionObservationMeasurements, ReceiverODProperties, SensorODProperties, and TransponderODProperties objects as seen in the example below:

GroundStation1.Antenna.OD.TimeTagBias.Sigma = 0.0001;

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EstimableVelocity

The EstimableVelocity object holds information about how velocity elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable velocities are always created as child objects of the CartesianOrbitStateEstimablePropertyContainer object as seen in the example below:

Spacecraft1.OD.Cartesian.VX.Sigma = 2e-005;

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EstimableVelocityBias

The EstimableVelocityBias object holds information about how velocity bias elements of an object's state are handled in the Orbit Determination / State Estimation process. This object is not creatable in script, but estimable velocity biases are always created as child objects of the MeasurementPointSolutionVX, MeasurementPointSolutionVY, and MeasurementPointSolutionVZ objects as seen in the example below:

(Spacecraft1.Receivers[0] AsType GPSReceiver).OD.PointSolutionObservation.VX.Bias.Sigma = 1e-005;

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EstimatorCovariance

The EstimatorCovariance object represents the total covariance associated with an Orbit Determination / State Estimation process.  The size of the covariance matrix itself is determined by the total number of items being estimated or considered in the process.

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FFEphemProperties

The FFEphemProperties object provides a collection of properties associated with reading and writing FreeFlyer-formatted ephemeris files. This object is not creatable in script, but is always created as a child object of the Ephemeris object, as seen in the example below:

Ephemeris1.FFEphemProperties.FormatVersion = 2;

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FFGroundObservationFile

The FFGroundObservationFile object provides functionalities for reading and writing GroundStationObservation data (azimuth, elevation, range, and range rate) to or from FreeFlyer's ASCII file format.  The time system for the epoch is TAI in Modified Julian format, range and range-rate data are given in km and km/s, and azimuth and elevation are given in radians in GS Local coordinates.

Mission

FileInterface

FreeFlyer supports the reading and writing of external ASCII and Binary files. The FileInterface object is a file stream interface that provides the mechanism by which data may be manipulated in and between files.

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FileProperties

The FileProperties object is used to query information about a file, in contrast to the FileInterface, which is used to determine information within a file. The FileProperties object provides a mechanism to retrieve the contents of a directory (DirectoryList) and determine if a filename points to a directory or a file (isDirectory).

This object has been Deprecated. Please use the static FileSystem object instead.

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FileSystem

The FileSystem object provides a native interface to perform simple and common file operations like copying, moving, and deleting, while also offering the ability to create and manage directories.

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FiniteBurn

The FiniteBurn models the effect of a finite thrust maneuver on a Spacecraft orbit. See Finite Burns for more information.

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FiniteBurnODProperties

The FiniteBurnODProperties object allows the user to access all the properties of the FiniteBurn object that relate to Orbit Determination processing. This includes all Estimable Properties for the FiniteBurn object. This object is not creatable in script, but is always created as a child object of the FiniteBurn object as seen in the example below:

FiniteBurn1.OD.ThrustOffsetDeltaX.Sigma = 0.05;

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FlagData

The FlagData object is a container for Clock Event, Clock Prediction, Orbit Prediction, and Maneuver flags associated with format Version C of the SP3PreciseEphemerisFile object. The SP3EphemerisFile object contains arrays of FlagData values for each of the four types of FlagData listed above. This object is not creatable in script, but is always created as a child of the SP3EphemerisFile object.

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ForceModel

The ForceModel object defines the forces that will be modeled in the accelerations that are applied when a Spacecraft or Formation is propagated.

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Formation

The Formation object is an extended List<Spacecraft> which provides additional visualization options.

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FrequencyRampSchedule

The FrequencyRampSchedule object allows the user to configure the frequency ramping information for a GroundAntenna, which is used for processing DSN data. This object is not creatable in script, but is always created as a child object of the GroundAntenna object as seen in the example below:

GroundStation1.Antenna.FrequencyRampingSchedule.GetFrequencyAtEpoch(epoch);

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FuzzySet

The FuzzySet object makes it possible to create conditional logic statements whose boundaries are not defined by a single value, but rather by a range of values of differing degrees of importance to the control of the system. See expanded description.

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GarbageCollector

FreeFlyer has a garbage collector that automatically cleans up memory associated with objects that are no longer being used in your Mission Plan. The GarbageCollector object allows you to enable or disable automatic garbage collection, and perform manual garbage collection if desired.

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GlobeAtmosphereLayer

The GlobeAtmosphereLayer object holds information about how the atmosphere is rendered on a CelestialObject's globe. This object is not creatable in script, but is always created as a child object of the GlobeOptions object as seen in the example below:

Earth.Globe.AtmosphereLayer.UseCloudMap = 1;

See the Globe Layers page for more information.

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Mission

GlobeBoundaryLayer

The GlobeBoundaryLayer object holds information about how boundary layers like coastlines are rendered on a CelestialObject's globe. This object is not creatable in script, but an array of GlobeBoundaryLayers is always created as a child object of the GlobeOptions object as seen in the example below:

Earth.Globe.BoundaryLayers[0].FillInterior = 1;

See the Globe Layers page for more information.

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GlobeLineLayer

The GlobeLineLayer object holds information about how line layers like political boundaries are rendered on a CelestialObject's globe. This object is not creatable in script, but an array of GlobeLineLayers is always created as a child object of the GlobeOptions object as seen in the example below:

Earth.Globe.LineLayers[0].Color = ColorTools.Yellow;

See the Globe Layers page for more information.

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GlobeLocationLayer

The GlobeLocationLayer object holds information about how location layers like cities are rendered on a CelestialObject's globe. This object is not creatable in script, but an array of GlobeLocationLayers is always created as a child object of the GlobeOptions object as seen in the example below:

Earth.Globe.LocationLayers[0].Color = ColorTools.Yellow;

See the Globe Layers page for more information.

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GlobeOptions

The GlobeOptions object lets you control the display of any CelestialObject, including the rendering of its surface textures, planetary atmosphere, coastlines, political boundaries, and custom user-specified lines or location markers. You can access the globe options for a CelestialObject through the CelestialObject.Globe property. You can assign GlobeOptions objects using the = operator. See the Globe Layers page for more information.

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GlobeSurfaceLayer

The GlobeSurfaceLayer object holds information about how the surface textures are rendered on a CelestialObject's globe. This object is not creatable in script, but is always created as a child object of the GlobeOptions object as seen in the example below:

Earth.Globe.SurfaceLayer.UseDaytimeImage = 1;

GlobeSurfaceLayer objects can be configured using .jpg and .png format image files.

See the Globe Layers page for more information.

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GNSSMeasurementOptions

The GNSSMeasurementOptions object is a container for accessing all options related to the GNSSObservation for a GNSS constellation. This object is not creatable in script, but is always created as a child object of the GNSSObservationMeasurements object as seen in the example below:

Spacecraft1.GNSSReceivers[0].OD.GPS.Pseudoranges[0].Noise = 0.1;

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GNSSObservation

The GNSSObservation objects holds pseudorange (one-way range) Measurements associated with a Global Navigation Satellite System (GNSS) constellation satellite's signal being processed by a GNSSReceiver on a Spacecraft at an instant in time.  The Measurements for a GNSSObservation are denoted by Rinex Measurement Codes.

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GNSSObservationBase

The GNSSObservationBase object is a base type for the objects used when working with GNSS observation data. See GNSS Observations for more information.

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GNSSObservationMeasurements

The GNSSObservationMeasurements object is a container for all measurement noise and bias information related to the GNSSObservation. The GNSSObservationMeasurements object holds the data associated with the ClockBias and ClockDrift Estimable Bias, the GalileoInterSystemBias for the Galileo constellation, and the noise and bias data for any included Rinex measurement codes. This object is not creatable in script, but is always created as a child object of the GNSSReceiverODProperties object as seen in the example below:

Spacecraft1.GNSSReceivers[0].OD.GNSSObservation.ClockBias.Value = 0.1;

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GNSSOptions

The GNSSOptions object is a container for processing options for RinexObsFile data and GNSSObservations, including ionospheric correction modeling and measurement weighting. This object is not creatable in script, but is always created as a child object of the RinexObsFile and GNSSObservation objects as seen in the example below:

GNSSObservation1.Galileo.UseMeasurementWeighting = 0;

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GNSSReceiver

The GNSSReceiver object models the properties of an actual Global Navigation Satellite System (GNSS) receiver that might be on-board a spacecraft. It is used specifically in the processing of GPS point solution and GNSS pseudorange data in an Orbit Determination / State Estimation process.

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GNSSReceiverODProperties

The GNSSReceiverODProperties object allows the user to access the list of EstimableProperties that are associated with a GNSSReceiver. This object is not creatable in script, but is always created as a child object of the GNSSReceiver object as seen in the example below:

Spacecraft1.GNSSReceivers[0].OD.PointSolutionObservation.X.Noise = 0.03;

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GPSPivotPointSolutionFile

The GPSPivotPointSolutionFile object provides functionalities for reading and writing GPS Pivot Point Solution files.  This is an ASCII file of Point Solution data as put out by the Pivot GPS receiver. The time system is TAI, and position and velocity values are given in meters and m/s in ICRF.  

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GPSReceiver

The GPSReceiver object models the properties of an actual GPS receiver that might be on-board a spacecraft.  It is used specifically in the processing of GPS point solution and pseudorange data in an Orbit Determination / State Estimation process.

This object has been Deprecated. Please use GNSSReceiver instead.

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GraphicsOverlay

The GraphicsOverlay object is a collection of shapes that can be drawn in a 2D or 3D Mission View. Each shape can be used to add a line, annotation, point, triangle, triangle strip, or icon to the view. The position of each shape is specified relative to the body-fixed frame of the GraphicsOverlay's ReferenceObject. The properties and methods of the GraphicsOverlay are only available via FreeForm script.

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GraphicsOverlayShape

The GraphicsOverlayShape object is an element in an array of shapes accessed via the GraphicsOverlay Shapes array property.  Each GraphicsOverlayShape can be used to add a line, annotation, point, triangle, triangle strip, or icon to its parent GraphicsOverlay.

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GridCell

A GridCell object is used to hold strings and/or variables to display within a GridWindow.  This object is not creatable in script, but this object type is returned when using the GridWindow.GetCell() method, as seen in the example below:

GridWindow1.GetCell(0, 0).SetValue(12345);

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GridCellGroup

The GridCellGroup object is a collection of GridCell objects within a GridWindow.  This object is not creatable in script, but this object type is returned when using the GridWindow.GetAllCells(), GetCellGroup(), GetRow(), and GetColumn() methods, as seen in the examples below:

GridWindow1.GetAllCells().SetValue(12345);

GridWindow1.GetCellGroup(0, 1, 0, 1).SetValue(12345);

GridWindow1.GetRow(0).SetValue(12345);

GridWindow1.GetColumn(0).SetValue(12345);

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GridFont

The GridFont object is a container to hold font-related properties within a GridCells.  This object is not creatable in script, but an instance is always created as a child object of the GridCell and GridCellGroup objects, as seen in the examples below:

GridWindow1.GetCell(0, 0).Font.Bold = 1;

GridWindow1.GetAllCells().Font.Bold = 1;

You can assign GridFont objects using the = operator.

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GridWindow

The GridWindow object creates an Output Window that displays a group of strings and/or variables in a grid format with a user defined number of rows and columns.

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GroundAntenna

The GroundAntenna object is used to define the characteristics of tracking data being provided from the ground station. See the Orbit Determination Guide for more information.

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GroundAntennaODProperties

The GroundAntennaODProperties object allows the user to access the list of EstimableProperties that are associated with a GroundAntenna.  This object is not creatable in script, but is always created as a child object of the GroundAntenna object as seen in the example below:

GroundStation1.Antenna.OD.TimeTagBias.Sigma = 0.0001;

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GroundHeading

The GroundHeading propagator is a GroundVehicle propagator. This simple motion model uses the GroundVehicle's location and surface velocity as an input, and propagates the state forward in time when the Step command is called. See the GroundVehicles section of the Coverage and Contact Analysis Guide for more information.

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GroundObservationFile

The GroundObservationFile object is a base type that provides object-being-observed, observer, and measurement and correction type usage flag properties to the objects that derive from it.  See the Orbit Determination Guide for more information.

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GroundObservationMeasurements

The GroundObservationMeasurements object is a container for all measurement noise and bias information related to the GroundStationObservation. The GroundObservationMeasurements object holds the noise and bias data for the Azimuth, Elevation, Range, and RangeRate Measurement objects. This object is not creatable in script, but is always created as a child object of the GroundAntennaODProperties object as seen in the example below:

GroundStation1.Antenna.OD.GroundObservation.Azimuth.Noise = 0.1;

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GroundStation

A GroundStation is a tracking station used for determining line of sight contact with a Spacecraft. GroundStation Objects can be placed on any built-in or custom Celestial Body Objects. It is used to compute contact duration, antenna pointing, acquisition of signal (AOS), and loss of signal (LOS) information with a Spacecraft. See the Coverage and Contact Analysis guide for more information. You can assign GroundStation objects using the = operator. This will equalize the GroundStations' properties, but not the properties of the attached GroundAntenna objects.

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GroundStationObservation

The GroundStationObservation object holds Measurements associated with a GroundStation's observation of a Spacecraft at an instant in time.  The Measurements for a GroundStationObservation include Azimuth, Elevation, Range, and Range Rate by default.

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GroundStationODProperties

The GroundStationODProperties object allows the user to access the list of EstimableProperties that are associated with a GroundStation. This object is not creatable in script, but is always created as a child object of the GroundStation object as seen in the example below:

GroundStation1.OD.HeightBias.Sigma = 1e-006;

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GroundVehicle

The GroundVehicle object represents a moving object on the ground, with capabilities for modeling position, velocity, orientation, and sensors. GroundVehicles can be associated with a reference Terrain object so that the height of the GroundVehicle will stay constant with respect to the Terrain. Otherwise, GroundVehicles maintain a constant height with respect to the central body ellipsoid. See the GroundVehicles section of the Coverage and Contact Analysis Guide for more information.

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GroundWaypoints

The GroundWaypoints propagator is a GroundVehicle propagator. This motion model updates the GroundVehicle's position to follow a series of waypoints when the GroundVehicle is stepped. Waypoints are specified using epoch, latitude, and longitude. The waypoints can be interpolated using three different modes: step function, rhumb line, or geodesic path. See the GroundVehicles section of the Coverage and Contact Analysis Guide for more information.

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Hardware

The Hardware object is a base type for "subsystem" objects used in Coverage and Contact Analysis, Maneuvering, and Orbit Determination.

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HCW

The HCW propagator is a propagator that uses the HCW equations of motion to propagate a Spacecraft object forward in time. HCW propagation is always referenced against a specified Cartesian or curvilinear coordinate set and additionally requires an initial orbit reference from which to begin the HCW formulation.

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IAUIAGAttitudeAdvancer

The IAUIAGAttitudeAdvancer is used to specify the attitude model of a CelestialObject. See Celestial Objects for more information.

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ImpulsiveBurn

The ImpulsiveBurn is used to provide an instantaneous velocity change to a Spacecraft. See Impulsive Burns for more information.

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ImpulsiveBurnODProperties

The ImpulsiveBurnODProperties object allows the user to access all the properties of the ImpulsiveBurn object that relate to Orbit Determination processing. This includes all Estimable Properties for the ImpulsiveBurn object. This object is not creatable in script, but is always created as a child object of the ImpulsiveBurn object as seen in the example below:

ImpulsiveBurn1.OD.DeltaVOffsetDeltaX.Sigma = 0.05;

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Integrator

The Integrator object is a base type that provides tolerance, max tries, force model, and fixed step properties to the objects that derive from it. See the Stepping the Spacecraft Guide for more information.

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InterpolatedTank

The InterpolatedTank, also known as “Chemical Non-Spherical”, models a hardware component that can be configured on a Spacecraft along with chemical-powered thrusters to model a propulsion system. See Tanks for more information.

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IonosphereOptions

The IonosphereOptions object is an internal object used to hold the different configurable properties of the ionosphere model that is used when processing observations in an Orbit Determination / State Estimation process.

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IpoptOptions

The IpoptOptions object provides access to configuration parameters that are specific to the third party Ipopt optimization system.

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J2Mean

The J2 Mean propagator is a first-order propagator that accounts only for the Earth's J2 geopotential model (Earth oblateness). No other effects, such as the Sun, Moon, or atmospheric drag, are modeled. The J2Mean propagator only takes Right Ascension of the Ascending Node and Argument of Perigee rates into account. A comparison between a J2Mean propagation and a numeric integration using, for example, an RK89, depends largely on whether the initial integration state is close to the mean orbit.

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JsonInterface

The JsonInterface object allows FreeFlyer users to easily import and export JSON-formatted data. JSON, or JavaScript Object Notation, is a data file format that contains attribute-value pairs. The JsonInterface object is always used with a Struct that will contain the data to serialize to JSON format (or the data that has been deserialized from JSON format).

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KalmanFilterOD

The KalmanFilterOD object provides algorithms for performing Orbit Determination and State Estimation using a Kalman filter technique.  This allows observations to be processed sequentially, and potentially in real-time.  The sequential nature of the Kalman filter provides significant power and flexibility by allowing the user to manipulate settings interactively inside the estimation process. See the Orbit Determination Guide for more information.

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KalmanSmoother

The KalmanSmoother object provides smoothing capabilities to the KalmanFilterOD and UnscentedKalmanFilterOD object. The smoother techniques available are Fixed-Point and Fixed-Interval. See the Orbit Determination Guide for more information.

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LinearTangentSteering

The LinearTangentSteering object provides a collection of properties and methods associated with the linear tangent thrust steering method. This object is always created as a child object of the FiniteBurn object, as seen in the example below:

FiniteBurn1.LinearTangentSteering.LamdaDot = {0, 0, 0};

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List<Object>

The List object is an array of other FreeFlyer objects. The List is also a base type that provides a count property to the objects that derive from it.  See the Lists reference for more information.

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LookAngleFrame

The LookAngleFrame object defines a 2D field-of-view with look angle coordinates. It contains an orientation, a boresight axis, look angle ranges, and definition for what each look angle axis represents.

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MapViewpointOptions

The MapViewpointOptions object allows the user to configure a 2D map type Viewpoint object. This object is not creatable in script, but is always created as a child object of the Viewpoint object as seen in the example below:

Viewpoint1.MapView.CenterLatitude = 0;

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MatlabInterface

The MatlabInterface is used to establish communications between MATLAB and FreeFlyer. See the Matlab Guide for more information.

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Matrix

The Matrix object provides numerous properties and methods for calculating various matrix statistics and decompositions. FreeFlyer also supports a variety of matrix operations. These features enable users to perform many analyses in FreeFlyer, without needing to interface with external programs to execute complex calculations. You can assign Matrix objects using the = operator. See the Matrix, Array, and Variable Math Script Reference for more information.

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Measurement

The Measurement object is a container for details on a given measurement in an Observation.  The Measurement object holds the initial observed value plus statistics computed from processing the measurement in an Orbit Determination / State Estimation process.

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MeasurementAzimuth

The MeasurementAzimuth object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains azimuth data as seen in the example below:

Spacecraft1.Sensors[0].OD.SpacecraftObservation.Azimuth.Noise = 0.001;

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MeasurementCustom

The MeasurementCustom object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object as seen in the example below:

Spacecraft1.OD.CustomObservations[0].Measurements[0].Noise = 0.001;

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MeasurementDeclination

The MeasurementDeclination object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains declination data as seen in the example below:

Spacecraft1.Sensors[0].OD.SpacecraftObservation.Declination.Noise = 0.001;

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MeasurementElevation

The MeasurementElevation object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains elevation data as seen in the example below:

Spacecraft1.Sensors[0].OD.SpacecraftObservation.Elevation.Noise = 0.001;

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MeasurementGNSSPseudorange

The MeasurementGNSSPseudorange object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains GNSS pseudorange data as seen in the example below:

GNSSReceiver1.OD.GNSSObservation.GPS.Pseudoranges[0].Noise = 0.005;

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MeasurementOneWayDoppler

The MeasurementOneWayDoppler object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains one way Doppler data as seen in the example below:

GroundStation1.Antenna.OD.TDRSObservation.OneWayDoppler.Noise = 0.001;

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MeasurementPointSolutionPosition

The MeasurementPointSolutionPosition object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains point solution position data as seen in the example below:

GNSSReceiver1.OD.PointSolutionObservation.X.Bias.ProcessAction = 1;

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MeasurementPointSolutionVelocity

The MeasurementPointSolutionVelocity object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains point solution velocity data as seen in the example below:

GNSSReceiver1.OD.PointSolutionObservation.VX.Bias.ProcessAction = 1;

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MeasurementPseudorange

The MeasurementPseudorange object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains GNSS Pseudorange data as seen in the example below:

GNSSReceiver1.OD.GNSSObservation.GPS.Pseudoranges[0].Noise = 0.005;

This object has been Deprecated. Please use MeasurementGNSSPseudorange instead.

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MeasurementRange

The MeasurementRange object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains range data as seen in the example below:

Spacecraft1.Sensors[0].OD.SpacecraftObservation.Range.Noise = 0.001;

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MeasurementRangeRate

The MeasurementRangeRate object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains range rate data as seen in the example below:

Spacecraft1.Sensors[0].OD.SpacecraftObservation.RangeRate.Noise = 0.001;

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MeasurementRightAscension

The MeasurementRightAscension object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains right ascension data as seen in the example below:

Spacecraft1.Sensors[0].OD.SpacecraftObservation.RightAscension.Noise = 0.001;

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MeasurementTwoWayDoppler

The MeasurementTwoWayDoppler object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains two way Doppler data as seen in the example below:

GroundStation1.Antenna.OD.TDRSObservation.TwoWayDoppler.Noise = 0.001;

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MeasurementTwoWayRange

The MeasurementTwoWayRange object is a container for measurement noise, minimum and maximum values, and an Estimable Bias for this measurement. This object is not creatable in script, but is always created as a child object of any measurement object that contains two way range data as seen in the example below:

GroundStation1.Antenna.OD.TDRSObservation.TwoWayRange.Noise = 0.001;

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NloptOptions

The NloptOptions object provides access to configuration parameters that are specific to the third party Nlopt optimization system.

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Norad

The Norad Propagator implemented in FreeFlyer utilizes the SGP4 and SDP4 discussed in the "Methods for Propagation of NORAD Element Sets" by Felix R. Hoots and Ronald L. Roehrich, December 1980, compiled by TS Kelso December 31, 1988. See expanded description.

This object has been Deprecated. Please use SGP4 instead.

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NoradOrbitStateEstimablePropertyContainer

The NoradOrbitStateEstimablePropertyContainer object provides a collection of the Norad estimable properties for use when estimating the Spacecraft state in the Norad element set. This object is not creatable in script, but is always created as a child object of the SpacecraftODProperties object, as seen below:

Spacecraft1.OD.Norad.MeanMotion.Sigma = 0.001;

This object has been Deprecated. Please use Sgp4OrbitStateEstimablePropertyContainer instead.

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NoradStateEstimator

The NoradStateEstimator object allows the user to generate a Norad state by using a BatchLeastSquaresOD object which computes incremental state updates to converge on a solution

This object has been Deprecated. Please use SGP4StateEstimator instead.

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Object

A base type from which all other objects inherit the “Name” property. See the Working with Objects guide for more information on type casting.

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Observation

The Observation object is a base type that provides object-being-observed, observer, and observed epoch properties to the objects that derive from it.  See the Orbit Determination Guide for more information.

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ODEstimationProcess

The ODEstimationProcess object is a base type that provides covariance, maximum allowable sigma, objects to process, and step size properties to the objects that derive from it.  See the Orbit Determination Guide for more information.

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ODProperties

The ODProperties object is a base type that provides an array of estimable OD properties to the objects that derive from it.  See the Orbit Determination Guide for more information.

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ODThrustEventModelingData

The ODThrustEventModelingData object is a support object that FreeFlyer creates internally when users model a ThrustEvent as part of Orbit Determination processing, using the AddThrustEventToSequence method. This object is not creatable in script. See the Orbit Determination Guide for more information.

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OptimizationConstraint

The OptimizationConstraint object allows the user to access properties of any constraint being used in an optimization process. This object is not creatable in script, but can be added to an Optimizer object as seen in the example below. OptimizationConstraints that have been added to an Optimizer object can be accessed through properties and methods on the Optimizer object. See the Optimization Guide for more information.

Optimizer1.AddConstraint("con");

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OptimizationStateVariable

The OptimizationStateVariable object allows the user to access properties of any state variable being used in an optimization process. This object is not creatable in script, but can be added to an Optimizer object as seen in the example below. OptimizationStateVariables that have been added to an Optimizer object can be accessed through properties and methods on the Optimizer object. See the Optimization Guide for more information.

Optimizer1.AddStateVariable("var");

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Optimizer

The Optimizer object provides interfaces for defining and optimizing multi-variable user-defined objective functions. This object allows for the configuration of any number of state variables or constraints, and contains support for minimizing or maximizing an objective as well as solving the constraints for a feasible solution without an objective. The Optimizer object can be loaded with any of the supported third party optimization systems. See the Optimization Guide for more information.

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OptimizerOptions

The OptimizerOptions object is a base type that provides access to customization options for third party optimization libraries to the objects that derive from it. This object is not creatable in script. See the Optimization Guide for more information.

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OrbitStateObservation

The OrbitStateObservation type is a base type which contains observation (or measurement) data.

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OrbitStateObservationGenerator

The OrbitStateObservationGenerator object creates observations to use in the fit of a trajectory. The typical use case is for when generating a Norad state as part of the SGP4StateEstimator object.

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OutgassingEvent

The OutgassingEvent object models the unintentional release of propellant from a Spacecraft. The acceleration due to the release is modeled as an exponential decay. OutgassingEvents do not deplete mass from the Spacecraft. See Outgassing Events for more information.

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OutgassingEventODProperties

The OutgassingEventODProperties object allows the user to access all the properties of the OutgassingEvent object that relate to Orbit Determination processing. This includes all Estimable Properties for the OutgassingEvent object. This object is not creatable in script, but is always created as a child object of the OutgassingEvent object as seen in the example below:

OutgassingEvent1.OD.AccelerationOffsetDeltaX.Sigma = 0.05;

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OutputLayoutManager

The output layout of the workspace can be controlled by the OutputLayoutManager Object.  A default global instance of the OutputLayoutManager exists in every Mission Plan.  FreeFlyer allows users to manage the output layout by setting the size and location of output windows through FreeForm Script.  See the OutputLayout reference for more information about configuring the workspace.

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OutputWindow

The OutputWindow object is a base type that provides title and target display mode properties to the objects that derive from it.  See the Generating Output Guide for more information.

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PhaseCollocationOptions

The PhaseCollocationOptions object allows users to tune the collocation dynamical solver used with the TrajectoryPhase object.

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PhaseControlModel

The PhaseControlModel object allows users access to setting the ControlType used by the TrajectoryPhase. FreeFlyer currently supports three control models: ballistic (no control), simple thruster, and ideal solar sail. All control models and their associated variables are formulated in ICRF.

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PhaseIdealSolarSailOptions

The PhaseIdealSolarSailOptions object allows users to edit sail parameters such as Area and EfficiencyFactor for use with a TrajectoryPhase configured with an 'Ideal Sail' control type.

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PhaseSimpleThrusterOptions

The PhaseSimpleThrusterOptions object allows users to edit thruster parameters such as DutyCylce, Isp, and Thrust for use with a TrajectoryPhase configured with an 'Simple Thruster' control type.

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Plate

The Plate object can be used to create a model that represents the geometry of a Spacecraft to be used for higher fidelity Solar Radiation Pressure (SRP) modeling. Users can define the size and orientation of plates with respect to the Spacecraft Body Coordinate System, configure plates to track the Sun in either single-axis or two-axis rotation, and query the SRP force and torque generated by the PlateModel. See the Flat Plate Model guide for more information.

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PlateModel

The PlateModel object holds all the settings for the plate model and contains a list of Plates called Spacecraft.PlateModel.Plates[].Users have the ability to add Plates or a box of Plates to a PlateModel to easily model a Spacecraft's geometry. Users can query values such as a PlateModel's SRP force, torque, or incident area throughout the duration of the Spacecraft's propagation. Once the PlateModel is defined, users can visualize their flat plate model in Mission Views to visually confirm the plate configuration, including the plates' size, location, and normal direction. See the Flat Plate Model guide for more information.

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PlotAxis

The PlotAxis object is used to configure the axes of a PlotWindow object. This object is not creatable in script, but an instance is automatically created for the X, Y, R, and Theta axes of the PlotWindow object, as seen in the examples below:

PlotWindow1.XAxis.GridVisible = 0;

PlotWindow1.YAxis.GridVisible = 0;

PlotWindow1.RAxis.GridVisible = 0;

PlotWindow1.ThetaAxis.GridVisible = 0;

You can assign PlotAxis objects using the = operator.

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PlotBaseObject

The PlotBaseObject object is a base type for the objects used when plotting data.  See the Plotting Data Guide for more information.

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PlotFont

The PlotFont object is used to configure the fonts associated with a PlotWindow object. This object is not creatable in script, but an instance is always created as a child object of the PlotAxis, PlotLegend, and PlotTitle objects, as seen in the examples below:

PlotWindow1.XAxis.LabelsFont.Bold = 1;

PlotWindow1.Legend.Font.Bold = 1;

PlotWindow1.PlotTitle.Font.Bold = 1;

You can assign PlotFont objects using the = operator.

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PlotLegend

The PlotLegend object is used to configure the legend associated with a PlotWindow object. This object is not creatable in script, but an instance is always created as a child object of the PlotWindow object, as seen in the example below:

PlotWindow1.Legend.Location = 1;

You can assign PlotLegend objects using the = operator.

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PlotPolynomialSeries

The PlotPolynomialSeries object is used to configure the polynomial coefficients and display of a polynomial series on a plot. The polynomial is displayed as a smooth curve and has no associated data points. A PlotPolynomialSeries object can be created in FreeForm script and added or removed from a PlotWindow object, or created through the PlotWindow constructor.

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PlotScatterSeries

The PlotScatterSeries object is used to configure the data points and display of a scatter series on a plot. The data points can be displayed as lines and/or points. A PlotScatterSeries object can be created in FreeForm script and added or removed from a PlotWindow object, or created through the PlotWindow constructor.

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PlotSeries

The PlotSeries object is a base type that provides properties for configuring data labels, lines, and markers to the objects that derive from it. You can assign PlotSeries objects using the = operator. See the Plotting Data Guide for more information.

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PlotTemplate

A PlotTemplate provides a way to customize titles, subtitles or axis labels of a plot in conjunction with the Plot command. In addition, more general plot preferences can be changed and then used for several plots.

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PlotTitle

The PlotTitle object is used to configure the title associated with a PlotWindow object. This object is not creatable in script, but an instance is automatically created for the title and subtitle of the PlotWindow object, as seen in the examples below:

PlotWindow1.PlotTitle.Text = "Title";

PlotWindow1.PlotSubTitle.Text = "Subtitle";

You can assign PlotTitle objects using the = operator.

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PlotWindow

A PlotWindow displays graphical data in either a Cartesian or Polar coordinate system, with Monitor mode turned on or off.

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PointGroup

A PointGroup is a collection of points located on or near the central body's surface. Points are located by latitude, longitude and height. PointGroups are designed to support sensor coverage analysis, where sensor contact with each point is computed. See the PointGroups Guide for more information.

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PointGroupPoint

The PointGroupPoint object represents one point of a PointGroup, and its properties should be accessed using PointGroup indices: PointGroup1[0].Longitude = 10.

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PointSolutionFile

The PointSolutionFile object is a base type that provides object-being-observed, measuring receiver, and measurement type usage flag properties to the objects that derive from it.  See the Orbit Determination Guide for more information.

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PointSolutionObservation

The PointSolutionObservation objects holds Measurements associated with a GPSReceiver's observation of a Spacecraft at an instant in time.  The Measurements for a PointSolutionObservation includes spacecraft position and velocity.

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PointSolutionObservationMeasurements

The PointSolutionObservationMeasurements object is a container for all measurement noise and bias information related to the PointSolutionObservation. The PointSolutionObservationMeasurements object holds the data associated with the TimeTagBias Estimable Bias and the noise and bias data for the X, Y, Z, VX, VY, and VZ Measurement objects. This object is not creatable in script, but is always created as a child object of the ReceiverODProperties object as seen in the example below:

(Spacecraft1.Receivers[0] AsType GPSReceiver).OD.PointSolutionObservation.X.Noise = 0.03;

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Preferences

The Preferences object allows access to FreeFlyer options relating to file and path information and UserInterface options. The FF_Preferences object is a global instance of this base type.

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Propagator

The Propagator object is a base type that provides a step size property to the objects that derive from it.  See the Stepping the Spacecraft Guide for more information.

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ProximityZone

A ProximityZone is a volume attached to a Spacecraft for the purpose of determining or visualizing the proximity of other Spacecraft or points.

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PseudorangeObservation

The PseudorangeObservation objects holds pseudo-range (one-way range) Measurements associated with a GPS constellation satellite's signal being processed by a GPSReceiver on a Spacecraft at an instant in time.  The Measurements for a PseudorangeObservation can include C1, C2, P1, P2, and IonoFree.

This object has been Deprecated. Please use GNSSObservationBase instead.

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PseudorangeObservationMeasurements

The PseudorangeObservationMeasurements object is a container for all measurement noise and bias information related to the PseudorangeObservation. The PseudorangeObservationMeasurements object holds the data associated with the ClockBias and ClockDrift Estimable Bias and the noise and bias data for the C1, C2, P1, and P2 Measurement objects. This object is not creatable in script, but is always created as a child object of the ReceiverODProperties object as seen in the example below:

(Spacecraft1.Receivers[0] AsType GPSReceiver).OD.PseudorangeObservation.C1.Noise = 0.001;

This object has been Deprecated. Please use GNSSObservationMeasurements instead.

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RampTableEntry

The RampTableEntry object allows the user to configure the entries that make up the ramping schedule for a GroundAntenna.FrequencyRampingSchedule, which is used for processing DSN data. This object is not creatable in script, but an array of RampTableEntry objects is always created as a child object of the GroundAntenna.FrequencyRampingSchedule object as seen in the example below:

GroundStation1.Antenna.FrequencyRampingSchedule.Entries[0].FrequencyRate = 0.0; // Hz/second

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RandomNumberGenerator

The RandomNumberGenerator object allows the user the flexibility to specify any of the included algorithms to generate a random number. The user can set the seed for each RandomNumberGenerator object individually, which allows the pseudo-random number generators to generate consistent number sequences between multiple runs.

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Receiver

The Receiver object is a base type that provides a numeric ID property to the objects that derive from it.  See the Orbit Determination Guide for more information.

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ReceiverODProperties

The ReceiverODProperties object allows the user to access the list of EstimableProperties that are associated with a Receiver. This object is not creatable in script, but is always created as a child object of the Receiver object as seen in the example below:

(Spacecraft1.Receivers[0] AsType GPSReceiver).OD.PointSolutionObservation.X.Noise = 0.03;

This object has been Deprecated. Please use GNSSReceiverODProperties instead.

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ReferenceFrameIDs

This object type contains unique identifiers for CelestialObject-specific frames for use with the PositionConvert, VelocityConvert, and PositionVelocityConvert functions, as well as methods like Spacecraft.SetKeplerianState() and CelestialObject.GetCartesianStateAtEpoch().

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Region

A Region is a closed contour region on any CelestialObject's surface defined by a series of vertices. At a minimum, a Region must include at least 4 points. The first and last points must have the same value in order to close the shape. See the Regions Guide for more information.

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RelativeMotionUtilities

The RelativeMotionUtilities object type has a number of static properties and methods on it that enable a user to work with relative Spacecraft states in common rendezvous or proximity operations analyses. This object is not creatable in script.

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ReportInterface

The ReportInterface object provides the mechanism to collect data and text to be written to an ASCII file. Hint: use the FileInterface to convert a binary file to an ASCII file or an ASCII file to a binary file in the desired format.

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RFLink

The RFLink object can be attached to a Spacecraft for use in radio frequency (RF) analysis between GroundStation objects or other Spacecraft objects. The RFLink object can be used to determine a transmitter or receiver's effective gain, effective isotropically radiated power (EIRP), power, noise, signal to noise ratio (SNR), link margin, and free space path loss (FSPL). You can assign RFLink objects using the = operator. See the Coverage and Contact Analysis Guide for more information.

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RFLinkComponent

The RFLinkComponent object holds information about how the transmitter and receiver are modeled in an RFLink object. This object is not creatable in script, but RFLinkComponents are always created as child objects of the RFLink object as seen in the example below:

RFLink1.Transmitter.Power = 200;

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RinexNavFile

The RinexNavFile object provides functionalities for reading and writing Broadcast Ephemeris data to and from a Rinex Navigation file.  This is an ASCII file of GPS Broadcast Ephemeris data conforming to the RINEX standard.

RinexNavFiles (also known as GPS Broadcast Ephemerides) contain position, velocity, and clock information for all the satellites of the GPS constellation.  FreeFlyer has the ability to read and write RinexNavFiles, but does not generate Broadcast Ephemeris data when propagating spacecraft.  The time system is GPS Time, and positions and velocities are in the ECEF reference frame, which FreeFlyer converts into the ICRF frame.

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RinexObsFile

The RinexObsFile object provides functionalities for reading and writing PseudorangeObservation data (C1, C2, P1, P2) to and from a Rinex Observation file.  This is an ASCII file of Pseudorange data conforming to the RINEX standard.  The time system is GPS Time, and the scalar pseudorange data is given in meters and is reference frame independent.

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RK45

The Runge Kutta 4(5) propagator uses 4th order Runge-Kutta propagation with 5th order error control to propagate the Spacecraft orbit. See expanded description.

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RK78

The Runge Kutta 7(8) propagator uses 7th order Runge-Kutta propagation with 8th order error control to propagate the Spacecraft orbit. See expanded description.

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RK78VOP

The Runge Kutta 7(8) VOP propagator is a method for propagating a Spacecraft's orbit that is based on a Variation of Parameters (VOP) formulation of the equations of motion. See expanded description.

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RK89

The Runge Kutta 8(9) propagator uses 8th order Runge-Kutta propagation with 9th order error control to propagate the spacecraft orbit. See expanded description.

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RotatingLibrationPoint

The RotatingLibrationPoint allows the user to set up a Rotating Libration Point coordinate system using either CelestialObject or CelestialSystem objects as the gravitational centers of the system for both usage and visualization. The states of spacecraft centered on L1-L5 points can be retrieved relative to the two centers.

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RotatingPulsatingSystem

The RotatingPulsatingSystem allows the user to set up a rotating-pulsating coordinate system using either CelestialObject or Spacecraft objects as the primary and secondary bodies of the system. You can compute and assign Spacecraft object states in the rotating-pulsating frame.

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RotatingPulsatingViewpointOptions

The RotatingPulsatingViewpointOptions object allows the user to configure a rotating-pulsating Viewpoint. This object is not creatable in script, but is always created as a child object of the Viewpoint object as seen in the example below:

Viewpoint1.RotatingPulsatingView.PrimaryObject = Earth.ObjectId;

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Sensor

The Sensor object can model unobstructed conical FOV sensors, rectangular (such as slit) sensors, irregularly shaped FOV sensors, and sensor obscurations. See the Sensors Guide for more information.

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SensorODProperties

The SensorODProperties object allows the user to access all the properties of the Sensor object that relate to OrbitDetermination processing. This includes all Estimable Properties for the Sensor object as well as measurement noise and bias properties associated with SpacecraftObservations. This object is not creatable in script, but is always created as a child object of the Sensor object as seen in the example below:

Spacecraft1.Sensors[0].OD.SpacecraftObservation.RangeRate.Noise = 0.1;

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SensorViewpointOptions

The SensorViewpointOptions object allows the user to configure a sensor view type Viewpoint object. This object is not creatable in script, but is always created as a child object of the Viewpoint object as seen in the example below:

Viewpoint1.SensorView.FieldOfView = 45;

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SequentialFilter

The SequentialFilter object is a base type that provides many common properties to the objects that derive from it: the KalmanFilterOD, UnscentedKalmanFilterOD, and SquareRootInformationFilterOD objects.  See the Orbit Determination Guide for more information.

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SGP4

The SGP4 object provides access to the United States Space Force SGP4 propagation algorithm, included in FreeFlyer's installation package through the AstroStds library. The included DLL files are stored in the FreeFlyer installation directory under "Support Files\Engine\Third Party\64_Bit\AstroStdsSgp4Prop". This directory also includes a license file to enable users to access the open source SGP4 implementation. This library also supports the SGP4-XP algorithm, which is used with TLE data in ephemeris type 4 format and includes Solar Radiation Pressure modeling. See the Two-Line Element Set File page for more information.

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Sgp4OrbitStateEstimablePropertyContainer

The Sgp4OrbitStateEstimablePropertyContainer object provides a collection of the SGP4 estimable properties for use when estimating the Spacecraft state in the SGP4 element set. This object is not creatable in script, but is always created as a child object of the SpacecraftODProperties object, as seen below:

Spacecraft1.OD.SGP4.MeanMotion.Sigma = 0.001;

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SGP4Properties

The SGP4Properties object provides a collection of properties associated with the SGP4/SGP4-XP propagator. This object is not creatable in script, but is always created as a child object of the Spacecraft object, as seen in the example below:

Spacecraft1.SGP4Properties.AGOM = 0.001;

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SGP4StateEstimator

The SGP4StateEstimator object allows the user to generate a SGP4 state by using a BatchLeastSquaresOD object which computes incremental state updates to converge on a solution.

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Smoother

The Smoother object is a base type that provides the CalculateSmoothedState method to the objects that derive from it. See the Orbit Determination Guide for more information.

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SnoptOptions

The SnoptOptions object provides access to configuration parameters that are specific to the third party Snopt optimization system.

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Socket

The Socket object allows you to send and receive data to and from a remote program via TCP/IP. See the Sockets Guide for more information.

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SolarSystem

The SolarSystem object allows access to FreeFlyer options relating to planetary constants and default files. The FF_SolarSystem object is a global instance of this base type.

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SP3EphemerisFile

The SP3Ephemeris file, also known as “Precise Ephemeris,” contains data records for the orbit and clock states for the entire GPS constellation. There are two versions of the format, Version A and Version C; FreeFlyer supports the reading and writing of both versions. The data records are nominally provided at 15 minute intervals, the time system of the file is GPS time, and the reference frame for the orbit data is Earth-Centered-Earth-Fixed (ECEF). FreeFlyer automatically converts between ECEF and ICRF when reading and writing SP3EphemerisFiles.

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Spacecraft

The Spacecraft object is the heart of FreeFlyer. You can define the orbit and attitude states of a Spacecraft in a variety of element sets and reference frames, define physical attributes such as mass and drag area, add various subsystems, and control the motion model. See The Spacecraft Object Guide for more information. You can assign Spacecraft objects using the = operator. This will equalize the Spacecrafts' properties, but not the properties of any attached objects (such as Propagators, ForceModels, Tanks, Sensors, and Thrusters).

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SpacecraftCovariance

The SpacecraftCovariance object represents the covariance associated with a Spacecraft.  The size of the covariance matrix itself is equivalent to the total number of Spacecraft state elements being estimated or considered.  Note that the Spacecraft covariance can be propagated without being included in an Orbit Determination process.

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SpacecraftObservation

The SpacecraftObservation object holds Measurements associated with a Sensor attached to one Spacecraft observing another Spacecraft at an instant in time. The Measurements for a SpacecraftObservation can include Range, RangeRate, Azimuth, and Elevation. The Azimuth and Elevation measurements are computed relative to the reference frame of the observing Sensor.

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SpacecraftObservationFile

The SpacecraftObservationFile object provides functionality for reading and writing SpacecraftObservation data (azimuth/right ascension, elevation/declination, range, and range-rate) to or from FreeFlyer's ASCII file format. The time system for data contained in the SpacecraftObservationFile is TAI in Modified Julian format and range and range-rate data are given in km and km/s, respectively. Azimuth, elevation, right ascension, and declination data are given in radians in the reference frame of the observing Sensor. Lastly, the spacecraft observer position is given in km, in the ICRF inertial reference frame.

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SpacecraftObservationMeasurements

The SpacecraftObservationMeasurements object is a container for all measurement noise and bias information related to the SpacecraftObservation. The SpacecraftObservationMeasurements object holds the noise and bias data for the Azimuth, Elevation, Range, and RangeRate Measurement objects. This object is not creatable in script, but is always created as a child object of the SensorODProperties object as seen in the example below:

Spacecraft1.Sensors[0].OD.SpacecraftObservation.Azimuth.Noise = 0.1;

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SpacecraftODProperties

The SpacecraftODProperties object allows the user to access the list of EstimableProperties that are associated with a Spacecraft, and defines other properties which dictate how the Spacecraft Covariance is handled. This object is not creatable in script, but is always created as a child object of the Spacecraft object as seen in the example below:

Spacecraft1.OD.Cartesian.X.Sigma = 0.05;

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SpacecraftProcessNoise

The SpacecraftProcessNoise object allows the user to access the Process Noise rate matrix, as well as relevant configuration properties and methods. This object is always created as a child object of the SpacecraftODProperties object as seen in the example below:

Spacecraft1.OD.ProcessNoise.ReferenceFrame = "RIC";

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SphericalTank

The SphericalTank object models a hardware component that can be configured on a Spacecraft along with chemical-powered thrusters to model a propulsion system. See Tanks for more information.

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SpiceEphemeris

SPICE Files are ephemerides created and maintained by the Navigation and Ancillary Information Facility (NAIF) Node of the Planetary Data System. A CelestialObject’s movement can be specified using SPICE Files. See the Celestial Objects Guide for more information.

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SpiceFileReader

The SpiceFileReader object is used to gather data from a SpiceEphemeris object.

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SPKProperties

The SPKProperties object provides a collection of properties associated with writing SPICE SPK ephemeris files. This object is not creatable in script, but is always created as a child object of the Ephemeris object, as seen in the example below:

Ephemeris1.SPKProperties.SPKType = 13;

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SquareRootInformationFilterOD

The SquareRootInformationFilterOD object provides algorithms for performing Orbit Determination and State Estimation using a Square Root Information Filter technique. The Square Root Information Filter is a different formulation of the standard Extended Kalman Filter, where the square root of the information matrix (the inverse of the covariance) is propagated instead of the covariance. This formulation of the filter improves the stability and robustness of the filter in cases of poor observability or poor conditioning of the covariance. See the Orbit Determination Guide for more information.

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SquareRootInformationSmoother

The SquareRootInformationSmoother object provides smoothing capabilities to the SquareRootInformationFilterOD object. See the Orbit Determination Guide for more information.

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Star

The Star object stores the location of a star as a unit vector in the Mean of J2000 coordinate system.

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StarField

The StarField object stores an ordered list of records containing star data and makes available the stars’ geocentric inertial (GCI) positions and magnitudes. The star data stored in a StarField object can either be specified directly or read from a formatted star catalog. See also Stars in the Interplanetary Analysis Guide.

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StarMapViewpointOptions

The StarMapViewpointOptions object allows the user to configure a Star Map view type Viewpoint object. This object is not creatable in script, but is always created as a child object of the Viewpoint object as seen in the example below:

Viewpoint1.StarMapView.CenterDeclination = 20;

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String

A String object represents a set of characters. Strings can be used to contain text or descriptive information, calendar-based epochs, file names, and more. See Parsing Arbitrary String Data for more information. You can assign String objects using the = operator.

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StringArray

A StringArray is used to hold and manipulate a set of strings. The StringArray has N elements, indexed by n = 0,1,2...N-1. The number of elements in a StringArray can be set when the StringArray is created using square brackets.  If the number of elements is not specified, the StringArray will have ten elements. StringArray indices are accessed using square brackets. This example shows how to create a StringArray with three elements and assign a value to the first element:

StringArray StringArray1[3];

StringArray1[0] = "Test";

You can assign StringArray objects using the = operator.

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StringTokenizer

Parsing string data is accomplished via the StringTokenizer object. The StringTokenizer object breaks the string into tokens (relevant data) which are separated by delimiters (a character or sequence of characters marking the beginning or end of a unit of data).

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Structure

FreeFlyer script allows users to define Structs, which are collections of related FreeFlyer objects. Unlike Lists, Structs can contain many objects of different types. Structs can be passed as arguments into Procedures, effectively passing several related objects into the Procedure as a single argument. FreeFlyer Structs are also designed to allow users to easily import and export JSON data.

See the Structs page for more information on working with Structs.

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Tank

The Tank object is a base type that provides center of gravity, moment of inertia, orientation, and reference point properties to the objects that derive from it.  See the Maneuvering Guide for more information.

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TDRSObservation

The TDRSObservation object holds Measurements associated with a GroundStation's observation of a user spacecraft via a TDRS relay spacecraft at an instant in time.  The Measurements for a TDRSObservation can include one-way doppler, two-way doppler, and two-way range.

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TDRSObservationMeasurements

The TDRSObservationMeasurements object is a container for all measurement noise and bias information related to the TDRSObservation. The TDRSObservationMeasurements object holds the noise and bias data for the OneWayDoppler, TwoWayDoppler, and TwoWayRange Measurement objects. This object is not creatable in script, but is always created as a child object of the GroundAntennaODProperties object as seen in the example below:

GroundStation1.Antenna.OD.TDRSObservation.OneWayDoppler.Noise = 2;

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TDRSRelayObserverLink

The TDRSRelayObserverLink object is an internal object used to map TDRS spacecraft to specific ground stations, for use in processing TDRSObservation data. This object is not creatable in script, but an Array of TDRSRelayObserverLink objects is always available as a property of the TDRSUTDFFile object, as seen in the example below:

Report TDRSUTDFFile1.ObserverRelayLinks[0].Observer;

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TDRSTransponder

The TDRSTransponder object models the properties of a TDRS relay which connects an observed user spacecraft to a ground station.  These properties include frequency bands, time delays, etc.

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TDRSUTDFFile

The TDRSUTDFFile object provides functionalities for reading Tracking Data Relay System (TDRS) Observation data (one-way Doppler, two-way Doppler, two-way range) from binary files written in the 75-byte binary Universal Tracking Data Format (UTDF). The time system is UTC, and the scalar range and doppler data is given in km and Hz and is reference frame independent.

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Terrain

The Terrain object is used to model terrain features in FreeFlyer. Terrain can be considered when computing the height of a location on the Earth and when computing line-of-sight visibility between two objects, whether they are orbiting in space, or stationary or moving objects on the ground. See the Terrain Modeling Guide for more information.

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ThreeDModel

The ThreeDModel object allows for high fidelity control of an imported 3D model file. The 3D model can be displayed on a Spacecraft in a 3D view. Use the Spacecraft.SetThreeDModel(ThreeDModel) method to assign the ThreeDModel object to the calling Spacecraft.

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ThreeDViewpointOptions

The ThreeDViewpointOptions object allows the user to configure a 3D view type Viewpoint object. This object is not creatable in script, but is always created as a child object of the Viewpoint object as seen in the example below:

Viewpoint1.ThreeDView.Declination = 20;

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Thruster

The Thruster is a hardware component attached to a Spacecraft and associated with a fuel Tank. The Thruster object contains all the information generally associated with thruster hardware, including location, pointing, and performance information. See the Thrusters Guide for more information.

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ThrustEvent

The ThrustEvent object is a base type that provides attitude system and burn component properties to the objects that derive from it. See the Maneuvering Guide for more information.

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TimeUtilities

The TimeUtilities Object allows a user to convert an epoch, specified by a variable or calendar-formatted string, to a different time system.  See  the Parsing Dates and Times reference for more information about using the TimeUtilites Object.

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TLECatalog

The TLECatalog object is an extended List<TwoLineElement> which provides the capability to read and write a group of SGP4 states.

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TrackingDataEditor

The TrackingDataEditor object provides a means to visualize tracking data and manually mark individual measurements in an observation as valid or invalid. Filtered results are wrriten to a new file once the user has completed the editing process.

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TrackingDataFile

The TrackingDataFile object is a base type that provides data span start and end epochs, filename, and first and last observation properties to the objects that derive from it.  See the Orbit Determination Guide for more information.

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TrajectoryNode

The TrajectoryNode object represents an individual node within a TrajectoryPhase object. Nodes represent the discretized path of the TrajectoryPhase. Nodes are added to the underlying TrajectoryNodes of the TrajectoryPhase object through the TrajectoryPhase.AddNode() and TrajectoryPhase.AddNodes() methods.

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TrajectoryPhase

The TrajectoryPhase object represents a user configurable trajectory arc for solving generic optimal control problems in FreeFlyer. Users can configure and link multiple trajectory phases with varying control models including: ballistic, simple thruster, and ideal solar sail control models. Using the TrajectoryPhase object, users can add bounds and constraints to the optimization problem to reflect real world limits when optimizing the objective function.

The TrajectoryPhase object is added to the Optimizer using the Optimizer.AddTrajectoryPhase() method. When the Optimizer.LoadEngine() method is called, all variables and constraints associated with the added TrajectoryPhases will automatically be added to the optimization problem. No further action inside of the Optimizer evaluation loop is needed from the user in order to solve the constraints originating from TrajectoryPhases.

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Transponder

The Transponder object is a base type that provides receive frequency, transmit frequency, and delay properties to the objects that derive from it.  See the Orbit Determination Guide for more information.

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TransponderODProperties

The TransponderODProperties object allows the user to access the list of EstimableProperties that are associated with a Transponder. This object is not creatable in script, but is always created as a child object of the Transponder object as seen in the example below:

Spacecraft1.Transponders[0].OD.TransponderDelay.Sigma = 0.0001;

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Trk234File

The Trk234File object provides functionality for reading DSN data from binary files written in the TRK-2-34 format. FreeFlyer extracts sequential range data (SRA), Total Count Phase (TCP) data, and frequency ramping data. FreeFlyer internally converts the ambiguous sequential range data (in Range Units) to DSNObservation.Range measurements (in km) and Total Count Phase (in counts) to DSNObservation.RangeRate measurements (in km/s) using the frequency ramp tables.

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TwoBody

The Two Body propagator is a simple orbit propagator which assumes unperturbed central force motion. See expanded description.

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TwoLineElement

The TwoLineElement object gives access to a suite of tools used for TLE reading and writing.

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UnscentedKalmanFilterOD

The UnscentedKalmanFilterOD object provides algorithms for performing Orbit Determination and State Estimation using the Scaled Unscented Transformation and non-linear filtering techniques. Like the traditional Kalman Filter, the UnscentedKalmanFilterOD object allows observations to be processed sequentially, and potentially in real-time. The advantage of an Unscented Kalman Filter is that it propagates the covariance of the state using the full non-linear motion model. A group of representative “sigma points” are selected to approximate the covariance at a given epoch; these sigma points are then propagated through the non-linear force model to the subsequent epoch and the covariance is reconstructed. Furthermore, measurement partial derivatives are not required; the measurement sensitivities are computed based on the predicted measurements for each of the sigma points. This creates a filter that provides more realistic covariance propagation and more robust convergence.  See the Orbit Determination Guide for more information.

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UserInterface

A UserInterface object is a container for displaying a custom input dialog using the Show command. See the User Interfaces Guide for more information.

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UTDFFile

The UTDFFile object provides functionalities for reading GroundStation Observation data (azimuth, elevation, range, range rate) from 75-byte binary files written in the Universal Tracking Data Format (UTDF).  The time system is UTC, and the angle data is given as azimuth and elevation in GS Local coordinates.

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Valve

The Valve object provides the capability to model thrusters that utilize multiple tanks. The tanks could be bi-propellant, redundant supplies, or both. See the Valves Guide for more information.

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Variable

A Variable object represents a number. Variables can be used as counters in For loops, indices in Arrays, flags for conditional control, mathematical operations, and more. See the Matrix, Array, and Variable Math Script Reference for more information. You can assign Variable objects using the = operator.

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Vector

Vectors can be displayed in 2D and 3D visualizations, easily determine the magnitude and direction to a specified target, and calculate intersections with Proximity Zones or define custom coordinate systems. See the Vectors and Coordinate Systems Guide for more information.

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Vehicle

The Vehicle object is a base type that provides epoch, position, velocity, orientation, propagator, and visualization properties to the objects that derive from it, as well as methods for computing various geometry, and the ability to add Sensors.

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ViewFont

The ViewFont object allows users to configure a set of Font options and apply them to any ViewWindow. You can assign ViewFont objects using the = operator.

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Viewpoint

A viewpoint specifies the camera position and orientation in 3D space, the field of view angle, and view mode. You can assign Viewpoint objects using the = operator.

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ViewWindow

A ViewWindow displays the specified objects in either a 3D View, 2D Map, Celestial Sphere, or Sensor View.

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ViewWindowConfiguration

The ViewWindowConfiguration object allows you to import and export the configuration of a ViewWindow, including the display settings for every object in the ViewWindow, and all of the viewpoints in the ViewWindow. See the ViewWindows page for more information.

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ViewWindowOutputProperties

The ViewWindowOutputProperties object allows you to control settings for the View Output Properties menu. This object is not creatable in script, but is always created as a child object of the ViewWindow object as seen in the example below:

ViewWindow1.OutputProperties.SetPageVisibility(0, 0);

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VirtualArray

The VirtualArray object provides properties and methods for expressions that evaluate to an Array. One example of an expression that evaluates to an Array is Array.Reverse().

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VirtualMatrix

The VirtualMatrix object provides properties and methods for expressions that evaluate to a Matrix. One example of an expression that evaluates to a Matrix is Matrix.Inverse().

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VirtualMatrixColumnWise

The VirtualMatrixColumnWise object provides an interface for calculating column-wise statistics of a Matrix. Column-wise statistics are accessed using the Matrix.ColumnWise syntax. For example, to calculate the sum of each column of a Matrix, the syntax Matrix1.ColumnWise.Sum is used.

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VirtualMatrixRowWise

The VirtualMatrixRowWise object provides an interface for calculating row-wise statistics of a Matrix. Row-wise statistics are accessed using the Matrix.RowWise syntax. For example, to calculate the sum of each row of a Matrix, the syntax Matrix1.RowWise.Sum is used.

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VirtualObjectArray

The VirtualObjectArray object provides properties and methods for expressions that evaluate to an Array of Objects. One example of an expression that evaluates to an Array of Objects is Spacecraft.Sensors.

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VirtualString

The VirtualString object provides properties and methods for expressions that evaluate to a String. One example of an expression that evaluates to a String is String.ToLower.

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VirtualStringArray

The VirtualStringArray object provides properties and methods for expressions that evaluate to a StringArray. One example of an expression that evaluates to a StringArray is StringArray.Reverse().

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VirtualVariable

The VirtualVariable object provides properties and methods for expressions that evaluate to a Variable. One example of an expression that evaluates to a Variable is Spacecraft.A.

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VisibilityCalculator

The VisibilityCalculator object allows users to work with multiple VisibilitySegments at once in order to determine whether any or all of the segments are simultaneously true.

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VisibilitySegment

The VisibilitySegment object allows users to determine whether an observer can see a target, based on the user-specified configuration for occulting bodies, celestial object shape models, and refraction.  

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WatchWindow

A WatchWindow creates an output window that displays a list of expressions and their current values in a color-coded tabular format.

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WindowOverlay

The WindowOverlay object is a collection of shapes that can be drawn over any ViewWindow. The position of each shape can be defined with respect to the viewable area of the ViewWindow or an object displayed within the ViewWindow.

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WindowOverlayEllipseOptions

The WindowOverlayEllipseOptions object allows the user to configure an Ellipse shape in a WindowOverlay object. This object is not creatable in script, but is always created as a child object of the WindowOverlayShape object, as seen below:

WindowOverlay1.Shapes[0].EllipseOptions.BorderWidth = 2;

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WindowOverlayImageOptions

The WindowOverlayImageOptions object allows the user to configure an Image shape in a WindowOverlay object. This object is not creatable in script, but is always created as a child object of the WindowOverlayShape object, as seen below:

WindowOverlay1.Shapes[0].ImageOptions.AspectRatio = 0;

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WindowOverlayLinesOptions

The WindowOverlayLinesOptions object allows the user to configure a set of lines as a Lines shape in a WindowOverlay object. This object is not creatable in script, but is always created as a child object of the WindowOverlayShape object, as seen below:

WindowOverlay1.Shapes[0].LinesOptions.Count = 5;

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WindowOverlayPointsOptions

The WindowOverlayPointsOptions object allows the user to configure a set of points as a Points shape in a WindowOverlay object. This object is not creatable in script, but is always created as a child object of the WindowOverlayShape object, as seen below:

WindowOverlay1.Shapes[0].PointsOptions.Count = 5;

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WindowOverlayRectangleOptions

The WindowOverlayRectangleOptions object allows the user to configure a Rectangle shape in a WindowOverlay object. This object is not creatable in script, but is always created as a child object of the WindowOverlayShape object, as seen below:

WindowOverlay1.Shapes[0].RectangleOptions.BorderWidth = 2;

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WindowOverlayShape

The WindowOverlayShape object is an element in an array of shapes accessed via the WindowOverlay Shapes array property. Each WindowOverlayShape can be used to add an ellipse, image, rectangle, text box, or groups of lines, points, and triangles to its parent WindowOverlay. This object is not creatable in script, but an Array of WindowOverlayShape objects is always created as a child object of the WindowOverlay object, as seen below:

WindowOverlay1.Shapes[0].Visible = 1;

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WindowOverlayTextOptions

The WindowOverlayTextOptions object allows the user to configure a Text shape in a WindowOverlay object. This object is not creatable in script, but is always created as a child object of the WindowOverlayShape object, as seen below:

WindowOverlay1.Shapes[0].TextOptions.BackdropBorderWidth = 2;

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WindowOverlayTrianglesOptions

The WindowOverlayTrianglesOptions object allows the user to configure a set of triangles as a Triangles shape in a WindowOverlay object. This object is not creatable in script, but is always created as a child object of the WindowOverlayShape object, as seen below:

WindowOverlay1.Shapes[0].TrianglesOptions.Count = 5;

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