[#1359] Add setters for initial spacecraft potentials

Author: leahkiner

src/simulation/environment/spacecraftChargingDynamics/_UnitTest/test_spacecraftChargingDynamics.py

@@ -34,6 +34,15 @@
 temp_photons = 2.0  # [eV] Photoelectron temperature
 flux_photons = 1e-6  # [A/m^2] Photoelectron flux
 
+@pytest.mark.parametrize(
+    ("servicer_potential_init", "target_potential_init"),  # ([Volts], [Volts])
+    [
+        (0.0, 0.0),
+        (-5000.0, -5000.0),  # GEO eclipse
+        (10.0, 10.0),  # GEO sunlit
+        (11000.0, 0.0)  # Electron beam should not reach target
+    ]
+)
 @pytest.mark.parametrize(
     ("servicer_radius", "target_radius"),  # ([m], [m])
     [
@@ -47,6 +56,8 @@
 @pytest.mark.parametrize("electron_beam_current", [0.0, 0.001, 250e-6])  # [Amps]
 @pytest.mark.parametrize("electron_beam_alpha", [0.0, 0.5, 1.0])  # [-]
 def test_spacecraft_charging_dynamics(show_plots,
+                                      servicer_potential_init,
+                                      target_potential_init,
                                       servicer_radius,
                                       target_radius,
                                       bulk_velocity_ions,
@@ -69,6 +80,8 @@ def test_spacecraft_charging_dynamics(show_plots,
     **Test Parameters**
 
     Args:
+        servicer_potential_init (float): [Volts] Servicer initial potential
+        target_potential_init (float): [Volts] Target initial potential
         servicer_radius (float): [m] Servicer spacecraft radius
         target_radius (float): [m] Target spacecraft radius
         bulk_velocity_ions (float): [m/s] Bulk velocity of plasma ions
@@ -85,7 +98,7 @@ def test_spacecraft_charging_dynamics(show_plots,
     task_name = "unitTask"
     process_name = "TestProcess"
     sim = SimulationBaseClass.SimBaseClass()
-    test_time_step_sec = 1e-6
+    test_time_step_sec = 1e-7
     test_process_rate = macros.sec2nano(test_time_step_sec)
     test_process = sim.CreateNewProcess(process_name)
     test_process.addTask(sim.CreateNewTask(task_name, test_process_rate))
@@ -161,6 +174,8 @@ def test_spacecraft_charging_dynamics(show_plots,
     capacitance = 1e-9  # [farads]
     spacecraft_charging = spacecraftChargingDynamics.SpacecraftChargingDynamics()
     spacecraft_charging.ModelTag = "SpacecraftChargingDynamics"
+    spacecraft_charging.setServicerPotentialInit(servicer_potential_init)
+    spacecraft_charging.setTargetPotentialInit(target_potential_init)
     spacecraft_charging.setServicerCapacitance(capacitance)
     spacecraft_charging.setTargetCapacitance(capacitance)
     spacecraft_charging.setFluxPhotoelectrons(flux_photons)
@@ -207,7 +222,7 @@ def test_spacecraft_charging_dynamics(show_plots,
 
     # Run the simulation
     sim.InitializeSimulation()
-    sim_time = 0.0001  # [s]
+    sim_time = 0.00001  # [s]
     sim.ConfigureStopTime(macros.sec2nano(sim_time))
     sim.ExecuteSimulation()
 
@@ -272,8 +287,8 @@ def test_spacecraft_charging_dynamics(show_plots,
         target_electron_beam_current_list_truth.append(target_electron_beam_current)
 
     # Compute servicer and target potential truth information
-    servicer_potential_list_truth = [0.0]
-    target_potential_list_truth = [0.0]
+    servicer_potential_list_truth = [servicer_potential_init]
+    target_potential_list_truth = [target_potential_init]
     for idx in range(len(timespan)-1):
         servicer_potential = servicer_potential_list_sim[idx]
         target_potential = target_potential_list_sim[idx]
@@ -551,6 +566,8 @@ def compute_electron_beam_current(electron_beam_current,
 if __name__ == "__main__":
     test_spacecraft_charging_dynamics(
         False,  # show_plots
+        0.0,  # [Volts]
+        0.0,  # [Volts]
         4.0,  # [m]
         2.0,  # [m]
         400000.0,  # [m/s]

src/simulation/environment/spacecraftChargingDynamics/spacecraftChargingDynamics.cpp

@@ -323,6 +323,34 @@ void SpacecraftChargingDynamics::postIntegration(uint64_t integrateToThisTimeNan
     this->timeBefore = integrateToThisTimeNanos*NANO2SEC;
 }
 
+/*! Setter for the initial servicer potential.
+ @param potentialInit [Volts] Servicer initial potential
+*/
+void SpacecraftChargingDynamics::setServicerPotentialInit(const double potentialInit) {
+    this->servicerPotentialInit = potentialInit;
+}
+
+/*! Setter for the initial target potential.
+ @param potentialInit [Volts] Target initial potential
+*/
+void SpacecraftChargingDynamics::setTargetPotentialInit(const double potentialInit) {
+    this->targetPotentialInit = potentialInit;
+}
+
+/*! Getter for the servicer initial potential.
+ @return double
+*/
+double SpacecraftChargingDynamics::getServicerPotentialInit() const {
+    return this->servicerPotentialInit;
+}
+
+/*! Getter for the target initial potential.
+ @return double
+*/
+double SpacecraftChargingDynamics::getTargetPotentialInit() const {
+    return this->targetPotentialInit;
+}
+
 /*! Setter for the servicer spacecraft capacitance.
  @param capacitance [farad] Servicer spacecraft capacitance
 */

src/simulation/environment/spacecraftChargingDynamics/spacecraftChargingDynamics.h

@@ -47,6 +47,10 @@ class SpacecraftChargingDynamics : public DynamicObject{
     void preIntegration(uint64_t callTimeNanos) final;  //!< Pre-integration method
     void postIntegration(uint64_t callTimeNanos) final;  //!< Post-integration method
 
+    void setServicerPotentialInit(const double potentialInit);  //!< Setter for the initial servicer potential
+    void setTargetPotentialInit(const double potentialInit);  //!< Setter for the initial target potential
+    double getServicerPotentialInit() const;  //!< Getter for the initial servicer potential
+    double getTargetPotentialInit() const;  //!< Getter for the initial target potential
     void setServicerCapacitance(const double capacitance);  //!< Setter for the servicer capacitance
     void setTargetCapacitance(const double capacitance);  //!< Setter for the target capacitance
     double getServicerCapacitance() const;  //!< Getter for the servicer capacitance
@@ -91,10 +95,10 @@ class SpacecraftChargingDynamics : public DynamicObject{
     BSKLogger bskLogger;  //!< BSK Logging
 
 private:
-    double servicerCapacitance{1e-9};  //!< [farads] Servicer capacitance
-    double targetCapacitance{1e-9};  //!< [farads] Target capacitance
     double servicerPotentialInit{};  //!< [Volts] Initial servicer potential
     double targetPotentialInit{};  //!< [Volts] Initial target potential
+    double servicerCapacitance{1e-9};  //!< [farads] Servicer capacitance
+    double targetCapacitance{1e-9};  //!< [farads] Target capacitance
     double servicerSurfaceArea{};  //!< [m^2] Servicer surface area
     double targetSurfaceArea{};  //!< [m^2] Target surface area
     double servicerSunlitArea{};  //!< [m^2] Servicer sunlit area

src/simulation/environment/spacecraftChargingDynamics/spacecraftChargingDynamics.rst

@@ -5,6 +5,9 @@ electric potential of two spacecraft (a servicer and a target) in a plasma envir
 ordinary differential equation for each spacecraft. The charging model includes plasma electron current, plasma
 ion current, photoelectric current, and an optional electron beam current.
 
+.. note::
+    while this module defaults all module member variables, there is a setter method available for each attribute.
+
 Message Connection Descriptions
 -------------------------------
 The following table lists all module input and output messages.
@@ -58,7 +61,7 @@ See the following journal paper for a detailed description of the charging equat
 
 .. note::
 
-    C. Hammerl and H. Schaub, `“Servicing and Target Spacecraft Charging Behavior Due to Emission of an
+    J. Hammerl and H. Schaub, `“Servicing and Target Spacecraft Charging Behavior Due to Emission of an
     Electron Beam” <https://hanspeterschaub.info/PapersPrivate/Hammerl2024a.pdf>`_.
 
 The module computes the total current on each spacecraft as the sum of:
@@ -101,9 +104,9 @@ correctly computes the photoelectric current, electron beam current, plasma elec
 current acting on both spacecraft. While the module defaults many required variables, the user has the ability
 to configure all information describing the electrons, ions, and photons using setter methods.
 
-The test varies the servicer and target size, the electron beam parameters, and the bulk plasma ion velocity. The test
-checks that the module correctly computes the photoelectric current, electron beam current, plasma electron current,
-and plasma ion current acting on both spacecraft.
+The test varies the initial spacecraft potentials and sizes, the electron beam parameters, and the bulk plasma ion
+velocity. The test checks that the module correctly computes the photoelectric current, electron beam current,
+plasma electron current, and plasma ion current acting on both spacecraft.
 
 User Guide
 ----------
@@ -191,8 +194,10 @@ The following steps are required to set up the ``spacecraftChargingDynamics`` mo
     capacitance = 1e-9  # [F]
     charging_dynamics = spacecraftChargingDynamics.SpacecraftChargingDynamics()
     charging_dynamics.ModelTag = "SpacecraftChargingDynamics"
-    charging_dynamics.setServicerCapacitance(capacitance)
-    charging_dynamics.setTargetCapacitance(capacitance)
+    charging_dynamics.setServicerPotentialInit(0.0)  # [Volts]
+    charging_dynamics.setTargetPotentialInit(0.0)  # [Volts]
+    charging_dynamics.setServicerCapacitance(capacitance)  # [farads]
+    charging_dynamics.setTargetCapacitance(capacitance)  # [farads]
 
     charging_dynamics.setTempPhotoelectrons(2.0)  # [eV]
     charging_dynamics.setFluxPhotoelectrons(1e-6)  # [A/m^2]