Configuring the Mission Control Sequence
- Inserting and removing segments
- Copying and moving segments
- Segment parameters
- Segment properties
- Nested segments
- MCS options
- Configuring MCS propagators
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 and select Insert After from the shortcut menu. To insert a new segment before a given MCS segment, highlight the latter, right-click, and select Insert Before from the shortcut menu. In either case, a Segment Selection window appears, 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 inserts the new segment before the final Return.
To remove a segment from the MCS tree, select it and click Delete Segment (
) or press Delete. You can also right-click the segment and select Delete from the shortcut menu. A dialog box appears, 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, which has been cut or copied, after a given MCS segment, highlight the latter and click Paste (
) on the MCS toolbar. To paste a segment before a given MCS segment, highlight the latter, right-click the mouse, and select Paste Before from the shortcut 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 into the current MCS or into the MCS of any other Astrogator satellite object in the scenario.
Drag
You can move a segment by dragging 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 it. You can press or release the key at any point while dragging and the action will change from a move to a copy, as indicated by a plus sign below the icon. To drag a segment into an unexpanded sequence, hold the cursor over the sequence briefly, and it will expand. To cancel a drag action, press the Escape key.
Segment parameters
A segment's parameters appear to the right of the MCS when the segment is selected. Use the parameters to define the specific characteristics or performance of the segment when running the MCS 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
You can access a segment's properties by:
- Clicking Segment Properties (
) in the MCS toolbar - Right-clicking the segment and selecting Properties from the shortcut menu
- Double-clicking the segment
The properties of a segment primarily affect how it appears in STK's graphics windows and how its data is expressed in reports. Some informational fields do not appear in the graphics windows but exist simply to enable you to identify segments and make notes about its purpose or configuration.
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 should be relatively short. Internal spaces are permitted. |
| User Comment | Enter a text string to remind you later of the purpose and any special features of the segment. |
| Coord. 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 sets 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 Astrogator will apply the epoch, position, and velocity of the segment's final state, according to the b-plane's definition. |
| Apply Final State To B-Planes Now | Click this button to immediately apply the last calculated final state of the segment to all selected b-planes. |
After you finish editing the segment's properties, click to return to the Mission Control Sequence window.
Renaming segments in the MCS
Besides 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
- Right-clicking the segment and selecting Rename from the shortcut menu
- Clicking it a second time shortly after selecting it
Nested segments
Sequence and Target Sequence segments by default have nested subsequences of MCS segments. The example here shows nested Impulsive Maneuver and Propagate segments inside of a Target Sequence.
Like the MCS itself, a nested subsequence will end in a Return segment that you cannot delete. When working with nested segments it is important to use particular care when selecting a destination for new or moved segments, to ensure that the segment occurs inside or outside the subsequences as desired. In the MCS example above, if you want to insert a new segment within 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 ends up outside the nested subsequence.
MCS options
The MCS Options window contains controls that affect the manner in which the MCS runs. To open the MCS Options window, click MCS Options (
) in the MCS toolbar or right-click any segment and select MCS Options from the shortcut 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 this check box to draw the trajectory in the 2D/3D Graphics window as the ephemeris calculates during the current run. If selected, this process runs regardless of if there are any open graphics windows, which may result in a delay before the new run begins. |
| Draw Trajectory in 3D | |
| Update Animation Time for all Objects | If you selected either of the Draw Trajectory options, you can select this check box to have all other objects animated so that they appear at the proper position for the time being computed as Astrogator calculates the trajectory. |
| Clear DWC Graphics Before Each Run | Select this check box 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 runs regardless of if there are any open graphics windows, which may result in a delay before the new run begins. |
| Graphics Update Rate | Adjust the slider between "Lowest" and "Highest" to set the rate at which STK applies all the selected "as Trajectory is Calculated" options. The higher the rate, the smoother the updating appears in the 3D Graphics window. A higher rate creates 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 this check box to clear all additional b-plane points from any previous run, in all graphics windows, before the current run. |
| Propagate on Apply | Select this check box to propagate trajectories whenever you click or on the Orbit page. If you want to close the Properties Browser for the satellite without running the MCS, make certain you clear this check box. |
| Use Trajectory Segment Colors | The default is selected, meaning the trajectory segments appear in the 2D Graphics window in the colors selected for the respective segments. The 2D Graphics Attributes page is configured for Custom Intervals and each segment is assigned an interval. If you clear this check box, then the color of the trajectory is defined by the 2D Graphics Attributes page. |
| Save numbers in raw format for increased precision. | Select this check box to store satellite information in binary format, to preserve the maximum amount of precision. |
| Warn when AWB MCSEphemerisSegments are updated | The Analysis Workbench time interval set MCS EphemerisSegments is tied to an associated Astrogator MCS and STK may update it upon running the MCS if STK detects a significant change. This option enables message viewer warnings when STK updates the interval set. |
| Stopping Condition Time Tolerance | Define a time tolerance, which Astrogator applies to the 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 more than the trip value tolerance.
If you set this value to zero, Astrogator does not apply time tolerance. |
| 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:
|
| Enable Logging |
If you select this check box, you open the option to have target sequences 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 | The default is that the check box is selected, meaning that a target sequence can affect controls within a nested target sequence besides its own. If you clear this check box, nested controls are unavailable to the parent target sequence, except for 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 you select this check box, Astrogator restores components or segments modified by a target sequence to their nominal values as soon as the target sequence completes its run. Otherwise, Astrogator does not restore modified items to nominal values until the entire MCS completes its run. |
| Active Profiles | Click to apply target sequence profile changes for all active profiles in the Mission Control Sequence (MCS). Click to clear all active target sequence profiles in the Mission Control Sequence (MCS) including auto-sequences. |
User Variables
Use the User Variables tab 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 enables you to select them for display during the calculation of the MCS. Click each graph that you want to display. To stop a selected graph from displaying, click it again to clear it. Select the Use Segment Colors check box 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 updates to reflect only the final satellite trajectory. Graph lines about intermediate targeter iterations are lost. If the graph had been using segment colors, this setting is lost and the graph line appears in a default color.
Configuring MCS segment propagators
In the MCS toolbar, you can click the Configure MCS Segment Propagators icon (
) to view and adjust the propagator and integrator settings for each segment. When you click the icon, the Configure MCS Propagators dialog box appears, enabling you to set parameters as described in the following sections.
Selecting segments for propagator and integrator change
Your first step in the dialog box will be to select the segment(s) for which you want to change the propagator and integrator. You can click to designate possible changes for all the MCS segments. Otherwise, click the Select check box next to individual segments listed in the Segment Properties section of the dialog box. You can clear all of your selections at any time by clicking .
Replacement specification
Next, specify the propagator and integrator to apply to the selected segments. You can do this individually for each selected segment in the list in the Segment Properties section of the dialog box. For a given selected segment, click the Propagator Name field and use the drop-down arrow to select a different propagator from the available list. You can also click the Integrator Name field and use its drop-down arrow to view integrator choices for the selected propagator.
To designate propagator and integrator selections for some or all of the selected segments, use the Replace with this propagator and the and integrator options.
When you use the available buttons to apply changes, Astrogator will apply the propagator named in the Replace with this propagator text field. To change this selection, click next to the text field and choose a different propagator from the list, which reflects the current propagator list in the Component Browser.
If you choose to change the integrator also, Astrogator will apply the integrator named in the and integrator text field. To change this selection, click next to the text field and choose a different integrator from the list. This list reflects the current integrators for the selected propagator, as designated in the Component Browser. If the ellipsis is unavailable, that means there is only one integrator choice for the selected propagator.
Applying the changes
To apply the propagator in the Replace with this propagator text field, you must choose one of the following radio buttons at the top of the dialog box:
- Replace All Propagators (default) - Astrogator will apply the propagator from the Replace with this propagator text field and the integrator from the and integrator text field to all the segments you selected.
- Replace Only Propagators that are Currently Set to - This is essentially a "find and replace" option. Astrogator will apply the propagator from the Replace with this propagator text field and the integrator from the and integrator text field to the segments you selected that are using the propagator named in the text field next to this option. To change this selection, click next to the text field and choose a different propagator from the list, which reflects the current propagator list in the Component Browser. You can see which segments are currently using this propagator by looking at the Propagator Name in the list of segments in the Segment Properties section of the dialog box.
Apply your specific propagator and integrator changes by clicking . This Apply button only affects the dialog box settings of the selected segments. You need to click to make the changes effective for the actual MCS segments.