Configuring the Mission Control Sequence

The Mission Control Sequence is defined by selecting and organizing segments in a manner that will produce your desired trajectory. By default, an Astrogator satellite's MCS contains Initial State and Propagate segments, each with default parameter values that produce a typical low earth orbit trajectory. Using the operations described in this section of the help, you can configure the MCS to perform the mission that you need.

Inserting and Removing Segments

To insert a new segment after a given MCS segment, highlight the latter and click Insert Segment () on the MCS toolbar or right-click the mouse and select Insert After from the popup menu. To insert a new segment before a given MCS segment, highlight the latter, right-click the mouse, and select Insert Before from the pop-up menu. In either case a Segment Selection window will appear, listing all available MCS segments, including any you have created in the Component Browser. If you highlight the final Return segment of the MCS, the Insert After option is not available, and clicking the toolbar button will insert the new segment before the final Return.

To remove a segment from the MCS tree, select it and click Delete Segment () or press Delete, or right-click it and select Delete from the popup menu. A dialog will appear giving you the option of confirming or canceling your action.

Copying and Moving Segments

To copy a segment in the MCS tree, highlight it and click Copy () on the MCS toolbar. To cut a segment from the MCS tree, click Cut (). To paste a segment that has been cut or copied after a given MCS segment, highlight the latter and click Paste () on the MCS toolbar. To paste a new segment before a given MCS segment, highlight the latter, right-click the mouse and select Paste Before from the menu.

If you highlight the final Return segment of the MCS, the Paste After option is not available, and clicking the toolbar button will paste the new segment before the final Return.

After cutting or copying a segment you can paste it as many times as you like in to the current MCS or into the MCS of any other Astrogator satellite object in the scenario.

Drag-and-Drop

You can move a segment by dragging and dropping it; select the desired segment and then click and drag it within the MCS. You can also create a copy of a segment rather than moving it by holding down the Control key while dragging and dropping it; you can press or release the key at any point while dragging and the action will change from a move to a copy (indicated by a plus sign below the icon) accordingly. To drag and drop a segment into an unexpanded sequence, hold the cursor over the sequence briefly, and it will expand. To cancel a drag-and-drop action, press the Escape key.

Segment Parameters

A segment's parameters are displayed to the right of the MCS when the segment is selected. The parameters are used to define the specific characteristics or performance of the segment when the MCS is run to calculate the satellite's trajectory. For help with configuring a segment's parameters, refer to the help page for the specific segment type.

Segment Properties

A segment's properties can be accessed by clicking Segment Properties () in the MCS toolbar or right-clicking the segment and selecting Properties from the menu that appears or, simply double-clicking the segment. The properties of a segment primarily affect how it will be displayed in STK's graphics windows and how its data will be expressed in reports; some informational fields are not displayed in the graphics windows, but exist simply to allow you to identify segments and make notes about its purpose or configuration that you may wish to reference at a later time.

The segment properties fields are defined in the following table; some properties are not applicable to all segments.

Field	Description
Name	Enter a text string to identify the segment. This string will appear in the MCS tree and, consequently, should be relatively short. Internal spaces are permitted.
User Comment	Enter a text string to remind you later of the purpose and/or any special features of the segment.
Coordinate System	Click and select a coordinate system for use in a Summary report.
Color	Select a color that will show up clearly on the selected background. This option is not available for segments that represent points in time or instantaneous actions - such as the Initial State segment - and do not result in any drawing in the 2D Graphics window.
Update animation time after running this segment	When selected, Astrogator will set the animation time to the final epoch of the segment when the segment finishes running.
Apply the final state of this segment to these B-Planes	Select a B-Plane or B-Planes to which the epoch, position, and velocity of the segment's final state will be applied, according to the B-Plane's definition.
Apply Final State To B-Planes Now	Click to immediately apply the last calculated final state of the segment to all selected B-Planes.

When you are finished editing the segment's properties, click OK to return to the Mission Control Sequence window.

Renaming Segments in the MCS

In addition to editing the Name field in the segment's properties window, you can rename any segment in the MCS by selecting it and pressing the F2 key, or clicking it a second time shortly after selecting it.

Nested Segments

The Sequence and Target Sequence segments produce nested subsequences of MCS segments, such as the nested Impulsive Maneuver and Propagate segments shown here:

Like the MCS itself, a nested subsequence will end in a Return segment that cannot be deleted. When working with nested segments it is important to use particular care when selecting a destination for new or moved segments, so that you ensure that the segment occurs inside or outside the subsequences as desired. In the MCS illustrated above, for example, if you want to insert a new segment in the target sequence after the nested Propagate segment ('Propagate 1 Hour'), you should highlight that segment and perform an Insert After, or highlight the nested Return segment (as shown above) and perform an Insert Before. If, instead, you highlight the unnested Finite Maneuver ('Plane Change'), the inserted segment will end up outside the nested subsequence.

MCS Options

The MCS Options window contains a number of controls that affect the manner in which the MCS is executed. To open the MCS Options window, click MCS Options () in the MCS toolbar or right-click any segment and select MCS Options from the pop-up menu. The window is comprised of four tabs - General, Targeting, User Variables, and Calculation Graphs.

General

The General tab contains controls for graphics display and other aspects of Astrogator's performance.

Option	Description
Draw Trajectory in 2D	Select to draw the trajectory in the 2D and/or 3D Graphics windows as the ephemeris is calculated during the current run. If selected, this process will be performed whether or not there are any open graphics windows, which may result in a delay before the new run is begun that has no apparent cause.
Draw Trajectory in 3D
Update Animation Time for all Objects	If either of the Draw Trajectory options is selected, you can select this option to have all other objects animated so that they appear at the proper position for the time being computed as the trajectory is calculated.
Clear DWC Graphics Before Each Run	Select to automatically clear all target iteration graphics of the previous run - in all graphics windows - before the current run draws new calculations. If selected, this process will be performed whether or not there are any open graphics windows, which may result in a delay before the new run is begun that has no apparent cause.
Graphics Update Rate	Adjust the slider between "Lowest" and "Highest" to set the rate at which all of the selected "as Trajectory is Calculated" options will be applied. The higher the rate, the smoother the updating will appear in the 3D Graphics window. A higher rate will create a greater processor demand, however, and may slow down the run of the MCS - depending on the computer you are using.
Clear Additional B-Plane Points Before Each Run	Select to clear all additional B-Plane points from any previous run - in all graphics windows - before the current run.
Propagate on Apply	Select to propagate trajectories whenever you click OK or Apply on the Orbit page. If you want to close the Properties Browser for the satellite without running the MCS, make certain this option is disabled.
Use Trajectory Segment Colors	If selected, trajectory segments are displayed in the 2D Graphics window in the colors selected for the respective segments; the 2D Graphics Attributes page will be configured for Custom Intervals and each segment will be assigned an interval. If this option is not selected, then the color of the trajectory is defined by the 2D Graphics Attributes page.
Save numbers in raw format for increased precision.	Select to store satellite information in binary format - to preserve the maximum amount of precision.
Stopping Condition Time Tolerance	Define a time tolerance, which will be applied with respect to desired trip values throughout the MCS. Astrogator will not refine its search for a desired trip value to a time step smaller than the time tolerance - even if the value range over the time step is in excess of the trip value tolerance. If this value is set to zero, time tolerance will not be applied.
Minimum Ephemeris Step	Define the minimum step size for saving ephemeris.

Targeting

The Targeting tab contains controls for Target Sequence performance.

Option	Description
Automatically Add As Active In All Differential Correctors	Select either or both: Segment Controls Segment Results
Enable Logging	If selected, target sequences can be set to produce 'run history' log files for differential corrector profiles. By default, a target sequence does not produce a log file.
Allow target sequences to use nested target sequence controls	If selected, a target sequence will be able to affect controls within a nested target sequence in addition to its own; otherwise, nested controls will be unavailable to the parent target sequence - with the exception of parameters defined for a Scripting Tool profile (which exist at the same logical level as the target sequence itself).
Restore nominal values as soon as target sequence completes	If selected, components or segments that are modified by a target sequence will be restored to their nominal values as soon as the target sequence completes its run; otherwise, modified items will not be restored to nominal values until the entire MCS completes its run.
Active Profiles	Click Apply All Changes to apply target sequence profile changes for all active profiles in the Mission Control Sequence (MCS); click Reset All to clear all active target sequence profiles in the Mission Control Sequence (MCS).

User Variables

The User Variables tab is used to define user variables for the mission. Enter the name and unit dimension of the variable.

Calculation Graphs

The Calculation Graphs tab provides a list of all XY and Time XY graphs that are available for the satellite in the Report and Graph manager and allows you to select them for display during the calculation of the MCS. Click on each graph that you want to display to select it. To stop a selected graph from displaying, click it again to deselect it. Select Use Segment Colors to display the graph lines in the segment colors used in the 2D and 3D Graphics windows.

If you click Refresh () on a calculation graph, the graph will be updated to reflect only the final satellite trajectory; graph lines pertaining to intermediate targeter iterations will be lost. If the graph had been using segment colors, this setting will be lost and the graph line will be displayed in a default color.