[#1332] Add eclipse message to facetedSRPEffector

Author: leahkiner

src/simulation/dynamics/facetedSRPEffector/_UnitTest/test_facetedSRPEffector.py

@@ -59,11 +59,14 @@
         np.array([0.05, -0.05, -0.05]),
     ]
 )
+@pytest.mark.parametrize("illumination_factor", [1.0, 0.5, 0.0])  # [-]
+
 def test_facetedSRPEffector(show_plots,
                             r_BN_N_init,
                             r_SN_N_init,
                             sigma_BN_init,
-                            omega_BN_B_init):
+                            omega_BN_B_init,
+                            illumination_factor):
     r"""
     **Verification Test Description**
 
@@ -82,8 +85,9 @@ def test_facetedSRPEffector(show_plots,
 
     This test sets up a simulation with a faceted spacecraft modeled as a cubic hub with two attached circular solar
     arrays. Six square facets represent the cubic hub and four circular facets represent the two solar arrays.
-    The test varies the initial state information of both the spacecraft and the Sun. The test checks that the computed
-    SRP forces and torques at each timestep match the values output from the module.
+    The test varies the initial state information of the spacecraft, the initial state information of the Sun, and the
+    Sun illumination factor. The test checks that the computed SRP forces and torques at each timestep match the
+    values output from the module.
 
     **Test Parameters**
 
@@ -92,6 +96,7 @@ def test_facetedSRPEffector(show_plots,
         r_SN_N_init (np.ndarray): [m] shape (3,) Initial Sun inertial position
         sigma_BN_init (np.ndarray): [-] shape (3,) Initial spacecraft inertial attitude
         omega_BN_B_init (np.ndarray): [rad/s] shape (3,) Initial spacecraft inertial angular velocity
+        illumination_factor (float): [-] Sun visibility factor (0 = full shadow, 1 = full sunlight)
 
     **Description of Variables Being Tested**
 
@@ -192,6 +197,11 @@ def test_facetedSRPEffector(show_plots,
     faceted_sc_projected_area.spacecraftStateInMsg.subscribeTo(sc_object.scStateOutMsg)
     test_sim.AddModelToTask(task_name, faceted_sc_projected_area)
 
+    # Create the eclipse message
+    eclipse_msg_data = messaging.EclipseMsgPayload()
+    eclipse_msg_data.illuminationFactor = illumination_factor
+    eclipse_msg = messaging.EclipseMsg().write(eclipse_msg_data)
+
     # Create the faceted SRP effector module
     faceted_srp_effector = facetedSRPEffector.FacetedSRPEffector()
     faceted_srp_effector.ModelTag = "facetedSRPEffector"
@@ -200,6 +210,7 @@ def test_facetedSRPEffector(show_plots,
         faceted_srp_effector.facetElementBodyInMsgs[idx].subscribeTo(facet_element_message_list[idx])
         faceted_srp_effector.facetProjectedAreaInMsgs[idx].subscribeTo(faceted_sc_projected_area.facetProjectedAreaOutMsgs[idx])
     faceted_srp_effector.sunStateInMsg.subscribeTo(sun_state_message)
+    faceted_srp_effector.sunEclipseInMsg.subscribeTo(eclipse_msg)
     sc_object.addDynamicEffector(faceted_srp_effector)
     test_sim.AddModelToTask(task_name, faceted_srp_effector)
     test_sim.AddModelToTask(task_name, sc_object)
@@ -244,7 +255,8 @@ def test_facetedSRPEffector(show_plots,
                                                                                sigma_BN,
                                                                                r_BN_N,
                                                                                r_SN_N,
-                                                                               facet_element_projected_area_list_sim)
+                                                                               facet_element_projected_area_list_sim,
+                                                                               illumination_factor)
 
     # Check the simulated srp force and torque values match the computed truth values
     for idx in range(len(timespan)):
@@ -267,7 +279,8 @@ def compute_srp_force_torque(num_facets,
                              sigma_BN,
                              r_BN_N,
                              r_SN_N,
-                             facet_element_projected_area_list_sim):
+                             facet_element_projected_area_list_sim,
+                             illumination_factor):
 
     srp_force_B_list_truth = []  # [N]
     srp_torque_B_list_truth = []  # [Nm]
@@ -302,8 +315,8 @@ def compute_srp_force_torque(num_facets,
                 srp_force_B += facet_force  # [N]
                 srp_torque_B += np.cross(facet_r_CopB_B_list[facet_idx], facet_force)  # [Nm]
 
-        srp_force_B_list_truth.append(srp_force_B)
-        srp_torque_B_list_truth.append(srp_torque_B)
+        srp_force_B_list_truth.append(illumination_factor * srp_force_B)
+        srp_torque_B_list_truth.append(illumination_factor * srp_torque_B)
 
     return np.array(srp_force_B_list_truth), np.array(srp_torque_B_list_truth)
 
@@ -314,5 +327,6 @@ def compute_srp_force_torque(num_facets,
         np.array([-4020338.690396649, 7490566.741852513, 5248299.211589362]),  # [m] r_BN_N_init
         np.array([0.0, 0.0, 0.0]),  # [m] r_SN_N_init
         np.array([0.0, 0.0, 0.0]),  # [-] sigma_BN_init
-        np.array([0.0, 0.0, 0.0])  # [rad/s] omega_BN_B_init
+        np.array([0.0, 0.0, 0.0]),  # [rad/s] omega_BN_B_init,
+        1.0  # [-] illumination_factor
     )

src/simulation/dynamics/facetedSRPEffector/facetedSRPEffector.cpp

@@ -105,6 +105,13 @@ void FacetedSRPEffector::computeForceTorque(double callTime, double timeStep) {
         return;
     }
 
+    // Read optional sun eclipse message
+    this->sunVisibilityFactor = 1.0;
+    if (this->sunEclipseInMsg.isLinked() && this->sunEclipseInMsg.isWritten()) {
+        EclipseMsgPayload sunEclipseIn = this->sunEclipseInMsg();
+        this->sunVisibilityFactor = sunEclipseIn.illuminationFactor;
+    }
+
     // Compute the sun direction unit vector in spacecraft body frame components
     Eigen::MRPd sigma_BN;
     sigma_BN = (Eigen::Vector3d)this->hubSigma->getState();
@@ -173,8 +180,8 @@ void FacetedSRPEffector::computeForceTorque(double callTime, double timeStep) {
     }
 
     // Update the force and torque vectors in the dynamic effector base class
-    this->forceExternal_B = totalSRPForcePntB_B;
-    this->torqueExternalPntB_B = totalSRPTorquePntB_B;
+    this->forceExternal_B = this->sunVisibilityFactor * totalSRPForcePntB_B;
+    this->torqueExternalPntB_B = this->sunVisibilityFactor * totalSRPTorquePntB_B;
 }
 
 /*! Setter method for the total number of spacecraft facets.

src/simulation/dynamics/facetedSRPEffector/facetedSRPEffector.h

@@ -26,6 +26,7 @@
 #include "architecture/_GeneralModuleFiles/sys_model.h"
 #include "architecture/utilities/bskLogging.h"
 #include "architecture/messaging/messaging.h"
+#include "architecture/msgPayloadDefC/EclipseMsgPayload.h"
 #include "architecture/msgPayloadDefC/FacetElementBodyMsgPayload.h"
 #include "architecture/msgPayloadDefC/ProjectedAreaMsgPayload.h"
 #include "architecture/msgPayloadDefC/SpicePlanetStateMsgPayload.h"
@@ -45,6 +46,7 @@ class FacetedSRPEffector: public SysModel, public DynamicEffector {
     std::vector<ReadFunctor<FacetElementBodyMsgPayload>> facetElementBodyInMsgs;  //!< List of facet geometry input data (Expressed in hub B frame)
     std::vector<ReadFunctor<ProjectedAreaMsgPayload>> facetProjectedAreaInMsgs;  //!< List of facet projected area input messages
     ReadFunctor<SpicePlanetStateMsgPayload> sunStateInMsg;  //!< Sun spice ephemeris input message
+    ReadFunctor<EclipseMsgPayload> sunEclipseInMsg;  //!< (optional) Sun eclipse input message
 
 private:
     /* Facet input message data */
@@ -58,6 +60,7 @@ class FacetedSRPEffector: public SysModel, public DynamicEffector {
     uint64_t numFacets{};  //!< Number of spacecraft facets
     StateData *hubPosition = nullptr;  //!< [m] Hub inertial position vector
     StateData *hubSigma = nullptr;  //!< Hub MRP inertial attitude
+    double sunVisibilityFactor = 1.0;  //!< Sun visibility factor (0 = full shadow, 1 = full sunlight)
 };
 
 #endif

src/simulation/dynamics/facetedSRPEffector/facetedSRPEffector.i

@@ -48,6 +48,9 @@ struct ProjectedAreaMsg_C;
 %include "architecture/msgPayloadDefC/SpicePlanetStateMsgPayload.h"
 struct SpicePlanetStateMsg_C;
 
+%include "architecture/msgPayloadDefC/EclipseMsgPayload.h"
+struct EclipseMsg_C;
+
 %pythoncode %{
 import sys
 protectAllClasses(sys.modules[__name__])

src/simulation/dynamics/facetedSRPEffector/facetedSRPEffector.rst

@@ -48,6 +48,9 @@ provides information on what each message is used for.
     * - facetProjectedAreaInMsgs
       - :ref:`ProjectedAreaMsgPayload`
       - Input message vector containing pre-computed per-facet projected areas
+    * - sunEclipseInMsg
+      - :ref:`EclipseMsgPayload`
+      - (Optional) Input msg for the Sun eclipse data. If connected, the SRP force and torque are scaled by the illumination factor (0 = full shadow, 1 = full sunlight)
 
 
 Module Functions
@@ -77,13 +80,14 @@ The unit test for this module is located in :ref:`test_facetedSRPEffector`. The
 correctly computes the aggregate SRP force and torque acting on the spacecraft due to impinging photons
 from the Sun. The test sets up a simulation with a faceted spacecraft modeled as a cubic hub with two attached
 circular solar arrays. Six square facets represent the cubic hub and four circular facets represent the two solar
-arrays. The test varies the initial state information of both the spacecraft and the Sun. Specifically, the test
-parameterizes:
+arrays. The test varies the initial state information of the spacecraft, the initial state information of the Sun,
+and the Sun illumination factor. Specifically, the test parameterizes:
 
     - Spacecraft initial inertial position
     - Sun inertial position
     - Spacecraft initial attitude
     - Spacecraft initial angular velocity
+    - Sun visibility (illumination) factor
 
 The test checks that the computed SRP forces and torques at each timestep match the values output from the module.
 
@@ -193,6 +197,10 @@ The following steps are required to set up the ``facetedSRPEffector`` module in
     faceted_sc_projected_area.sunStateInMsg.subscribeTo(sun_state_message)
     faceted_sc_projected_area.spacecraftStateInMsg.subscribeTo(sc_object.scStateOutMsg)
 
+#. Optionally, connect an eclipse message to account for shadow conditions. If connected, the computed SRP force and torque are scaled by the illumination factor (0.0 = full shadow, 1.0 = full sunlight)::
+
+    faceted_srp_effector.sunEclipseInMsg.subscribeTo(eclipse_msg)
+
 #. Add the SRP effector to the spacecraft::
 
     sc_object.addDynamicEffector(faceted_srp_effector)