Put

•"myVariable.FFObjectFile" is any text specifying a valid path and filename, including extension, of an XML formatted output file

•The FFephem, CCSDSOEM, STKephem, SPKephem, ephem, or PCephem keywords cause FreeFlyer to output specifically formatted ephemeris text files

•"SCephem.FFephem" is a FreeFlyer-formatted external ephemeris

•"SCephem.txt" is a CCSDS OEM-formatted external ephemeris

•"SCephem.e" is a STK-formatted external ephemeris

•"SCephem.bsp" is a SPICE-formatted external ephemeris

•"SCephem.ephem" is an HP (big endian) binary external ephemeris (Requires NASA Pack)

•"SCephem.PCephem" is a PC (little endian) binary external ephemeris (Requires NASA Pack)

•The Put command provides a mechanism to collect Spacecraft state data into an Ephemeris object.

oWhenever you want to add the Spacecraft's current state into the Ephemeris object, use the Put command.

oThis is often in a While loop, usually following Step and/or Maneuver commands.

oYou can also use the Ephemeris.AddVectorData() method instead of the Put command.

oSee the Creating an Ephemeris File page for more information and examples.

•If you want to automatically add all the states a Spacecraft will have over the entire Mission Plan simulation, you may want to Put the Spacecraft to the Ephemeris using the "as Global" option, as shown above.

oNote that the "as Global" option is scoped to the control statement it was called in. That is to say, when the "as Global" option is used inside of an If block, While loop, or For loop, all steps inside of the control statement will automatically be added; any steps taken outside of the control statement will NOT be added.

oYou can also employ the "Global" option using the checkbox shown on the Ephemeris Object editor.

oWhen the Ephemeris object has been initialized with the Global checkbox turned on, the associated Spacecraft's state will be added to the Ephemeris object automatically whenever the Spacecraft is stepped or maneuvered; therefore, no Put command from Spacecraft object to Ephemeris object is required.

oThis is particularly useful if the Mission Sequence is complex (multiple loops, maneuvers, etc.) or if the "Step To" syntax is used.

•Once all of the Spacecraft states have been collected into the Ephemeris object, the Put command can be used to generate an external ephemeris file.

oThis is usually at the end of the Mission Sequence.

oSeveral formats are available for the creation of external ephemeris files, including FreeFlyer ephemerides (*.FFephem), STK ephemerides (*.e), SPICE ephemerides (*.bsp), CCSDS ephemerides, and Goddard Space Flight Center Code 500 ephemerides (requires NASA pack).

oYou can also use the Ephemeris.GenerateEphemeris() method instead of the Put command.

oSee Ephemerides and AHF for more information.

•With the FreeFlyer ephemeris format in version 2 or higher, FreeFlyer has the ability to add custom columns.

oWhen adding custom columns, you can specify whether the value for the column will be automatically retrieved from a mapped Spacecraft property when the Put command is called, or if the value for the column will be explicitly provided to the Put command.

oIf a custom column is not mapped to a Spacecraft property, the value for this column must be explicitly provided to the Put command, as shown in the example above.

•The Assignment command can be used to set all the properties of one object equal to those of another object.

oThe Assignment command only supports certain object types: Variables, Arrays, Strings, StringArrays, Spacecraft, and GroundStations.

oThe Assignment command does not equalize the properties of any attached objects or subsystems (such as Propagators, ForceModels, Tanks, Thrusters, Sensors, and Antennas).

•One way to copy objects or subsystems that are not supported by the Assignment command is to use the Put and Get commands to put the first object out to a file and then load all the properties back in to a second object.

oThe example below shows how to equalize all the properties of two Spacecraft's Propagators and ForceModels:

•Any FreeFlyer Object type

•Default:

oFreeFlyer Object File

•For Spacecraft Objects:

oFreeFlyer Object File

oEphemeris Object - Adds the current Spacecraft state into the Ephemeris object

•For Ephemeris Objects:

oFreeFlyer Object File

oFreeFlyer Ephem - Writes the Ephemeris object stored states out to a FreeFlyer-formatted ephemeris file

oSTK Ephem - Writes the Ephemeris object stored states out to an STK-formatted ephemeris file

oSPICE Ephem - Writes the Ephemeris object stored states out to a SPICE-formatted ephemeris file

oCCSDS OEM - Writes the Ephemeris object stored states out to a CCSDS OEM-formatted ephemeris file

oGSFC Ephem (UNIX) (Requires NASA Pack)

oGSFC Ephem (PC) (Requires NASA Pack)

•Output file path and file name for object file or ephemeris

•Displays the FreeFlyer Script that is generated by the editor

•Displays descriptions of the editor and its fields

•Description text changes as the mouse pointer moves over the different fields within the editor