Level 2 FreeFlyer Certification Exam Part C

Design a Mission Plan that uses an electrical thruster to provide a 2 day burn in the orbit velocity direction to raise the semimajor axis of a Spacecraft's orbit. The Electric Thruster provides 0.1 N force and an Isp of 4000 sec. Create an “ElectricalMicrothrusterBurn.txt" file and update the file while the Spacecraft is maneuvering.

Spacecraft Spacecraft1;
FiniteBurn FiniteBurn1;
ElectricalTank ElectricTank;

Thruster ElecThruster;
Attach ElectricTank to Spacecraft1;
Attach ElecThruster to Spacecraft1;
Attach ElectricTank to ElecThruster;
ElecThruster.Type = "Electrical";
ElectricTank.TankMass = 2;


// Perform Manuever
WhileManeuvering Spacecraft1 using FiniteBurn1 generating "ElectricalMicrothrusterBurn.txt";

        View Spacecraft1;
End;

Design a Mission Plan that compares ImpulsiveBurns in two different attitude reference frames. Start by configuring a default Spacecraft, changing the Attitude Reference Frame to VNB and renaming the Spacecraft “VNB”. Clone the “VNB” Spacecraft, rename the object “UVW” and change the Attitude Reference Frame to “UVW”.

ImpulsiveBurn VNBBurn;
ImpulsiveBurn UVWBurn;

// VNB
VNBBurn.AttitudeSystem = 1;
VNBBurn.BurnDirection = {0,1,0};

// UVW
UVWBurn.AttitudeSystem = 5;
UVWBurn.BurnDirection = {0,0,1};

Maneuver VNB using VNBBurn generating "VNBImpulsiveBurn.txt";
Maneuver UVW using UVWBurn generating "UVWImpulsiveBurn.txt";

While (VNB.ElapsedTime <= TIMESPAN ( 1 days)); 
        Step VNB; 
        Step UVW to (VNB.Epoch==UVW.Epoch); 
        // Add output 
End;

Design a Mission Plan that Targets raising a Spacecraft’s semi-major axis to 7500 km using a FiniteBurn along the velocity vector.

Spacecraft Spacecraft1;
FiniteBurn FiniteBurn1;

InterpolatedTank InterpolatedTank1;
Thruster ChemThruster;
ChemThruster.Type = "Chemical";
ChemThruster.ThrusterC1 = 444.8; // Thrust (N)
ChemThruster.ThrusterK1 = 300; // Isp (sec)

// Attach hardware to the Spacecraft

Target;

        // Reset the Spacecraft at every iteration of the loop
        // Use the FiniteBurn.BurnDuration property as the Vary parameter
        // Maneuver the Spacecraft using the FiniteBurn
        // Achieve a SMA of 7500 km within 1 km tolerance

End;

Maneuver Spacecraft1 using FiniteBurn1 generating 'ManeuverReport.txt';

Design a Mission Plan that uses a two level targeter to raise the Spacecraft's semi-major axis to 6750 km and re-circularizes the orbit (i.e., Spacecraft1.E <= 0.0001) if the Spacecraft's height falls below 350 km during its 1000-day propagation.

Spacecraft Spacecraft1;
ImpulsiveBurn apogeeRaise;
ImpulsiveBurn recircularize;
Variable TargetApogee = 6750;

// Spacecraft Orbit Definition
Spacecraft1.SetKeplerianState({TargetApogee, 0.0001, 35, 0, 0 ,0});

// Set AttitudeSystem for both ImpulsiveBurns to VNB
While (Spacecraft1.ElapsedTime < TIMESPAN(1000 days)); 

        Step Spacecraft1; 

        // Minimize Plot to speed up execution 
        Plot Spacecraft1.ElapsedTime, Spacecraft1.Apogee; 
        
        // Target & execute 2 burns if Height falls to 350 km 
        If (Spacecraft1.Height <=350); 
        
        // Step the Spacecraft to perigee

        Target;

        // Reset the Spacecraft at every iteration of the loop
        // Use the apogeeRaise.BurnDirection[0] property as the Vary parameter
        // Maneuver the Spacecraft using the apogeeRaise
        // Achieve the TargetApogee within 1 km

        End;


        // Report out the Spacecraft's Epoch, Spacecraft's Mass, and the apogeeRaise BurnDirection
                                                
        // Step the Spacecraft to apogee


        Target;

        // Reset the Spacecraft at every iteration of the loop
        // Use the recircularize.BurnDirection[0] property as the Vary parameter and include a constraint to keep the burn within 0 to 0.01
        // Maneuver the Spacecraft using the recircularize
        // Achieve an eccentricity of 0.0001 within 0.00001  
      
        End;
                
        // Report out the Spacecraft's Epoch, Spacecraft's Mass, and the recircularize BurnDirection
                        
        End;
                                
End;