STK OBJECT MODEL TUTORIAL

Follow the instructions in the accompanying tutorial (a PDF file) to enter the following code into your Visual Studio project.

NOTE: Code fragments are tabbed in such a way that the indentation should be correct when you copy them into your project. When copying a line, be sure to select the entire line, starting from the left margin of the page.

* ------------------------------------------------------------- *
* SECTION: Add the Core of the STK Object Model to your Project *
* ------------------------------------------------------------- *

1) Add the following using statements to the beginning of Form1.cs:

using AGI.STKObjects;
using AGI.STKUtil;
using AGI.STKObjects.Astrogator;


2) Add these declarations to the beginning of the Form1 class definition:

		private AGI.STKObjects.AgStkObjectRoot root;
		private AGI.STKObjects.Astrogator.IAgVADriverMCS driver;


3) In the Form1 class constructor, after the InitializeComponent() method, add:

			root = new AGI.STKObjects.AgStkObjectRoot();
			

4) In the Form1 dispose method, immediately before the call to base.Dispose(), add:

				System.Runtime.InteropServices.Marshal.ReleaseComObject(root);
				root = null;

* ------------------------------ *
* SECTION: Create a New Scenario *
* ------------------------------ *

1) Create a scenario named "AstrogatorTutorial"

		public void NewScenario()
		{
			try
			{
				button1.Enabled = false;
				// first close any existing scenario
				root.CloseScenario();
				root.NewScenario("AstrogatorTutorial");
				
				// Reset the units to the STK defaults
				IAgUnitPrefsDimCollection dimensions = root.UnitPreferences;
				dimensions.ResetUnits();

				// Set the date unit, acquire an interface to the scenario and use
				// it to set the time period and epoch
				dimensions.SetCurrentUnit("DateFormat", "UTCG");
				IAgScenario scene= (IAgScenario)root.CurrentScenario;			
				scene.StartTime = "1 Jul 2009 00:00:00.00";
				scene.StopTime = "1 Jul 2009 04:00:00.00";
				
				scene.Epoch = "1 Jul 2009 00:00:00.00";
				button2.Enabled = true;
			}
			catch(Exception e)
			{
				MessageBox.Show(e.Message);
			}
		}

2) Add to Click event procedure for New Scenario button:

			NewScenario();
			
* ------------------------------------------- *
* SECTION: Create an Astrogator Satellite     *
* ------------------------------------------- *			
            
1) Create a satellite named "Satellite1" and get an interface to the Astrogator propagator 

        public void NewSatellite()
        {
            try
            {
                button2.Enabled = false;
                //Create a new satellite object
                IAgSatellite sat1 = root.CurrentScenario.Children.New(AgESTKObjectType.eSatellite,
                    "Satellite1") as IAgSatellite;

                //Set the propagator to Astrogator
                sat1.SetPropagatorType(AgEVePropagatorType.ePropagatorAstrogator);

                //get the Driver for the Propagator
                driver = sat1.Propagator as IAgVADriverMCS;

                //Clear all segments from the MCS
                driver.MainSequence.RemoveAll();

                button3.Enabled = true;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }
        }

2) Add to Click event procedure for New Satellite button:

            NewSatellite();

	
* ------------------------------------------- *
* SECTION: Configure the Initial State        *
* ------------------------------------------- *

1) Create an initial state segment and configure it
        
        public void InitialState()
        {
            try
            {
                //disable the Initial State Button
                button3.Enabled = false;

                IAgVAMCSInitialState initState = driver.MainSequence.Insert(
                    AgEVASegmentType.eVASegmentTypeInitialState, "Inner Orbit", "-") as IAgVAMCSInitialState;

				initState.SetElementType(AgEVAElementType.eVAElementTypeKeplerian);
				IAgVAElementKeplerian kep = initState.Element as IAgVAElementKeplerian;
				kep.PeriapsisRadiusSize = 6700;
				kep.ArgOfPeriapsis = 0;
				kep.Eccentricity = 0;
				kep.Inclination = 0;
				kep.RAAN = 0;
				kep.TrueAnomaly = 0;

                //Enable the Parking Orbit button
                button4.Enabled = true;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }
        }

2) Add to Click event procedure for Initial State button:

            InitialState();


* ------------------------------------------- *
* SECTION: Configure the Parking Orbit        *
* ------------------------------------------- *

1) Add a propagate segment to the MCS for the parking orbit.       

        public void ParkingOrbit()
        {
            try
            {
                button4.Enabled = false;

                IAgVAMCSPropagate propagate = driver.MainSequence.Insert(
                    AgEVASegmentType.eVASegmentTypePropagate, "Propagate", "-") as IAgVAMCSPropagate;

                propagate.PropagatorName = "Earth Point Mass";
                ((IAgVAMCSSegment)propagate).Properties.Color = Color.Blue;
                ((IAgVAStoppingCondition)propagate.StoppingConditions["Duration"].Properties).Trip = 7200;

                button5.Enabled = true;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }        
        }


2) Add to Click event procedure for Parking Orbit button:

            ParkingOrbit();


* ------------------------------------------- *
* SECTION: Configure the Target Sequence      *
*          for the First Maneuver             *
* ------------------------------------------- *


1) Create a target sequence that will find the magnitude of the first maneuver in the transfer

        public void FirstTargetSequence()
        {
            try
            {
                button5.Enabled = false;

                IAgVAMCSTargetSequence ts = driver.MainSequence.Insert(
                    AgEVASegmentType.eVASegmentTypeTargetSequence, "Start Transfer", "-") as
                    IAgVAMCSTargetSequence;

                IAgVAMCSManeuver dv1 = ts.Segments.Insert(
                    AgEVASegmentType.eVASegmentTypeManeuver, "DV1", "-") as IAgVAMCSManeuver;

                dv1.SetManeuverType(AgEVAManeuverType.eVAManeuverTypeImpulsive);
                IAgVAManeuverImpulsive impulsive = dv1.Maneuver as IAgVAManeuverImpulsive;
                impulsive.SetAttitudeControlType(AgEVAAttitudeControl.eVAAttitudeControlThrustVector);
                IAgVAAttitudeControlImpulsiveThrustVector thrustVector = impulsive.AttitudeControl as
                    IAgVAAttitudeControlImpulsiveThrustVector;
                thrustVector.ThrustAxesName = "Satellite/Satellite1 VNC(Earth)";
                dv1.EnableControlParameter(AgEVAControlManeuver.eVAControlManeuverImpulsiveCartesianX);
                ((IAgVAMCSSegment)dv1).Results.Add("Keplerian Elems/Radius of Apoapsis");

                IAgVAProfileDifferentialCorrector dc = ts.Profiles["Differential Corrector"] as
                    IAgVAProfileDifferentialCorrector;

                IAgVADCControl xControlParam = dc.ControlParameters.GetControlByPaths("DV1",
                    "ImpulsiveMnvr.Cartesian.X");
                xControlParam.Enable = true;
                xControlParam.MaxStep = 0.3;

                IAgVADCResult roaResult = dc.Results.GetResultByPaths("DV1", "Radius Of Apoapsis");
                roaResult.Enable = true;
                roaResult.DesiredValue = 42238;
                roaResult.Tolerance = 0.1;

                dc.MaxIterations = 50;
                ts.Action = AgEVATargetSeqAction.eVATargetSeqActionRunActiveProfiles;

                button6.Enabled = true;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }
        }

2) Add to Click event procedure for First Target Sequence button:

            FirstTargetSequence();

* ------------------------------------------- *
* SECTION: Configure the Transfer Orbit       *
* ------------------------------------------- *


1) Insert a propagate segment for the half ellipse from perigee to apogee in the transfer.

        public void TransferOrbit()
        {
            try
            {
                button6.Enabled = false;

                IAgVAMCSPropagate transferEllipse = driver.MainSequence.Insert(
                    AgEVASegmentType.eVASegmentTypePropagate, "Transfer Ellipse", "-") as IAgVAMCSPropagate;

                ((IAgVAMCSSegment)transferEllipse).Properties.Color = Color.Red;
                transferEllipse.PropagatorName = "Earth Point Mass";
                transferEllipse.StoppingConditions.Add("Apoapsis");
                transferEllipse.StoppingConditions.Remove("Duration");

                button7.Enabled = true;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }
        }

2) Add to Click event procedure for Transfer Orbit button:

            TransferOrbit();

* ------------------------------------------- *
* SECTION: Configure the Target Sequence      *
*          for the Second Maneuver            *
* ------------------------------------------- *

1) Insert the target sequence that will solve for the maneuver to circularize the final orbit
 
       public void SecondTargetSequence()
        {
            try
            {
                button7.Enabled = false;

                IAgVAMCSTargetSequence ts = driver.MainSequence.Insert(
                    AgEVASegmentType.eVASegmentTypeTargetSequence, "Finish Transfer", "-") as
                    IAgVAMCSTargetSequence;

                IAgVAMCSManeuver dv2 = ts.Segments.Insert(
                    AgEVASegmentType.eVASegmentTypeManeuver, "DV2", "-") as IAgVAMCSManeuver;
                dv2.SetManeuverType(AgEVAManeuverType.eVAManeuverTypeImpulsive);
                IAgVAManeuverImpulsive impulsive = dv2.Maneuver as IAgVAManeuverImpulsive;
                impulsive.SetAttitudeControlType(AgEVAAttitudeControl.eVAAttitudeControlThrustVector);
                IAgVAAttitudeControlImpulsiveThrustVector thrustVector = impulsive.AttitudeControl as
                    IAgVAAttitudeControlImpulsiveThrustVector;
                thrustVector.ThrustAxesName = "Satellite/Satellite1 VNC(Earth)";
                dv2.EnableControlParameter(AgEVAControlManeuver.eVAControlManeuverImpulsiveCartesianX);
                ((IAgVAMCSSegment)dv2).Results.Add("Keplerian Elems/Eccentricity");

                IAgVAProfileDifferentialCorrector dc = ts.Profiles["Differential Corrector"] as
                    IAgVAProfileDifferentialCorrector;

                IAgVADCControl xControlParam = dc.ControlParameters.GetControlByPaths("DV2",
                    "ImpulsiveMnvr.Cartesian.X");
                xControlParam.Enable = true;
                xControlParam.MaxStep = 0.3;

                IAgVADCResult eccResult = dc.Results.GetResultByPaths("DV2", "Eccentricity");
                eccResult.Enable = true;
                eccResult.DesiredValue = 0;
                eccResult.Tolerance = 0.001;

                dc.Mode = AgEVAProfileMode.eVAProfileModeIterate;
                ts.Action = AgEVATargetSeqAction.eVATargetSeqActionRunActiveProfiles;

                button8.Enabled = true;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }
        }

2) Add to Click event procedure for Second Target Sequence button:

            SecondTargetSequence();

  
* ------------------------------------------- *
* SECTION: Configure the Final Orbit          *
* ------------------------------------------- *

1)  Propagate the satellite for 1 day after the transfer

        public void FinalOrbit()
        {
            try
            {
                button8.Enabled = false;

                IAgVAMCSPropagate outerOrbit = driver.MainSequence.Insert(
                    AgEVASegmentType.eVASegmentTypePropagate, "Outer Orbit", "-") as IAgVAMCSPropagate;

                ((IAgVAMCSSegment)outerOrbit).Properties.Color = Color.Green;
                outerOrbit.PropagatorName = "Earth Point Mass";
                ((IAgVAStoppingCondition)outerOrbit.StoppingConditions["Duration"].Properties).Trip = 86400;

                button9.Enabled = true;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }
        }

2) Add to Click event procedure for Final Orbit button:

            FinalOrbit();

* ------------------------------------------- *
* SECTION: Run the MCS                        *
* ------------------------------------------- *

1) Run the MCS and apply the targeted values of the maneuvers to the segments.

        public void RunMCS()
        {
            try
            {
                driver.RunMCS();
                IAgVAMCSTargetSequence startTransfer = driver.MainSequence["Start Transfer"] as IAgVAMCSTargetSequence;
                IAgVAMCSTargetSequence finishTransfer = driver.MainSequence["Finish Transfer"] as IAgVAMCSTargetSequence;

                IAgVAProfileDifferentialCorrector startDC = startTransfer.Profiles["Differential Corrector"] as IAgVAProfileDifferentialCorrector;
                Console.WriteLine(startDC.ControlParameters.GetControlByPaths("DV1", "ImpulsiveMnvr.Cartesian.X").FinalValue);

                IAgVAProfileDifferentialCorrector finishDC = finishTransfer.Profiles["Differential Corrector"] as IAgVAProfileDifferentialCorrector;
                Console.WriteLine(finishDC.ControlParameters.GetControlByPaths("DV2", "ImpulsiveMnvr.Cartesian.X").FinalValue);

                Array dvComponents = new Array[3];

                IAgVAMCSManeuver dv1 = startTransfer.Segments["DV1"] as IAgVAMCSManeuver;
                IAgVAManeuverImpulsive dv1Impulsive = dv1.Maneuver as IAgVAManeuverImpulsive;
                IAgVAAttitudeControlImpulsiveThrustVector dv1ThrustVector = dv1Impulsive.AttitudeControl as IAgVAAttitudeControlImpulsiveThrustVector;
                dvComponents = dv1ThrustVector.QueryCartesian();
                Console.WriteLine(dvComponents.GetValue(0).ToString());
                startTransfer.ApplyProfiles();
                dvComponents = dv1ThrustVector.QueryCartesian();
                Console.WriteLine(dvComponents.GetValue(0).ToString());

                IAgVAMCSManeuver dv2 = finishTransfer.Segments["DV2"] as IAgVAMCSManeuver;
                IAgVAManeuverImpulsive dv2Impulsive = dv2.Maneuver as IAgVAManeuverImpulsive;
                IAgVAAttitudeControlImpulsiveThrustVector dv2ThrustVector = dv2Impulsive.AttitudeControl as IAgVAAttitudeControlImpulsiveThrustVector;
                dvComponents = dv2ThrustVector.QueryCartesian();
                Console.WriteLine(dvComponents.GetValue(0).ToString());
                finishTransfer.ApplyProfiles();
                dvComponents = dv2ThrustVector.QueryCartesian();
                Console.WriteLine(dvComponents.GetValue(0).ToString());
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }
        }

2) Add to Click event procedure for Run MCS button:

            RunMCS();