3 changed files with 1 additions and 489 deletions
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#include <catch2/catch_test_macros.hpp> |
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#include "../src/physics.h" |
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#include "../src/orbital_mechanics.h" |
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#include "../src/simulation.h" |
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#include "../src/config_loader.h" |
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#include "../src/test_utilities.h" |
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#include <cmath> |
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const double VELOCITY_TOLERANCE_APSIDES = 1.0; |
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const double POSITION_TOLERANCE_APSIDES = 1.0e3; |
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const double VELOCITY_TOLERANCE_TIMESTEP = 10.0; |
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const double POSITION_TOLERANCE_TIMESTEP = 1.0e4; |
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TEST_CASE("Propagation through perigee (velocity maximum)", "[analytical][propagation][perigee]") { |
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const double TIME_STEP = 60.0; |
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SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP); |
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REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml")); |
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Spacecraft* craft = &sim->spacecraft[0]; |
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CelestialBody* earth = &sim->bodies[0]; |
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Vec3 pos_before; |
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Vec3 vel_before; |
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craft->orbit.true_anomaly = M_PI / 4.0; |
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orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_before, &vel_before); |
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double v_before = vec3_magnitude(vel_before); |
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double r_before = vec3_magnitude(pos_before); |
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INFO("Before perigee:"); |
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INFO(" Position: (" << pos_before.x << ", " << pos_before.y << ", " << pos_before.z << ") m"); |
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INFO(" Velocity: (" << vel_before.x << ", " << vel_before.y << ", " << vel_before.z << ") m/s"); |
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INFO(" Velocity magnitude: " << v_before << " m/s"); |
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INFO(" Radius: " << r_before << " m"); |
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Vec3 pos_perigee; |
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Vec3 vel_perigee; |
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craft->orbit.true_anomaly = 0.0; |
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orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_perigee, &vel_perigee); |
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double v_perigee = vec3_magnitude(vel_perigee); |
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double r_perigee = vec3_magnitude(pos_perigee); |
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INFO("At perigee (v=0):"); |
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INFO(" Position: (" << pos_perigee.x << ", " << pos_perigee.y << ", " << pos_perigee.z << ") m"); |
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INFO(" Velocity: (" << vel_perigee.x << ", " << vel_perigee.y << ", " << vel_perigee.z << ") m/s"); |
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INFO(" Velocity magnitude: " << v_perigee << " m/s"); |
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INFO(" Radius: " << r_perigee << " m"); |
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double expected_r_perigee = craft->orbit.semi_major_axis * (1.0 - craft->orbit.eccentricity); |
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INFO("Expected radius at perigee: " << expected_r_perigee << " m"); |
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double r_error = fabs(r_perigee - expected_r_perigee); |
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INFO("Radius error: " << r_error << " m"); |
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REQUIRE(r_error < POSITION_TOLERANCE_APSIDES); |
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REQUIRE(v_perigee > v_before); |
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destroy_simulation(sim); |
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} |
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TEST_CASE("Propagation through apogee (velocity minimum)", "[analytical][propagation][apogee]") { |
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const double TIME_STEP = 60.0; |
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SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP); |
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REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml")); |
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Spacecraft* craft = &sim->spacecraft[0]; |
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CelestialBody* earth = &sim->bodies[0]; |
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Vec3 pos_perigee; |
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Vec3 vel_perigee; |
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craft->orbit.true_anomaly = 0.0; |
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orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_perigee, &vel_perigee); |
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double v_perigee = vec3_magnitude(vel_perigee); |
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double r_perigee = vec3_magnitude(pos_perigee); |
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INFO("At perigee:"); |
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INFO(" Velocity magnitude: " << v_perigee << " m/s"); |
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INFO(" Radius: " << r_perigee << " m"); |
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Vec3 pos_apogee; |
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Vec3 vel_apogee; |
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craft->orbit.true_anomaly = M_PI; |
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orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_apogee, &vel_apogee); |
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double v_apogee = vec3_magnitude(vel_apogee); |
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double r_apogee = vec3_magnitude(pos_apogee); |
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INFO("At apogee (v=π):"); |
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INFO(" Position: (" << pos_apogee.x << ", " << pos_apogee.y << ", " << pos_apogee.z << ") m"); |
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INFO(" Velocity: (" << vel_apogee.x << ", " << vel_apogee.y << ", " << vel_apogee.z << ") m/s"); |
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INFO(" Velocity magnitude: " << v_apogee << " m/s"); |
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INFO(" Radius: " << r_apogee << " m"); |
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double expected_r_apogee = craft->orbit.semi_major_axis * (1.0 + craft->orbit.eccentricity); |
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INFO("Expected radius at apogee: " << expected_r_apogee << " m"); |
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double r_error = fabs(r_apogee - expected_r_apogee); |
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INFO("Radius error: " << r_error << " m"); |
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REQUIRE(r_error < POSITION_TOLERANCE_APSIDES); |
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REQUIRE(v_apogee < v_perigee); |
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REQUIRE(r_apogee > r_perigee); |
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destroy_simulation(sim); |
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} |
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TEST_CASE("Propagation returns to initial state after one orbital period", "[analytical][propagation][period]") { |
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const double TIME_STEP = 60.0; |
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SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP); |
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REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml")); |
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Spacecraft* craft = &sim->spacecraft[0]; |
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CelestialBody* earth = &sim->bodies[0]; |
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double a = craft->orbit.semi_major_axis; |
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double mu = G * earth->mass; |
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double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu); |
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INFO("Semi-major axis: " << a << " m"); |
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INFO("Orbital period: " << period_seconds << " s (" << period_seconds / 3600.0 << " hours)"); |
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Vec3 pos_initial; |
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Vec3 vel_initial; |
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orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_initial, &vel_initial); |
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INFO("Initial position: (" << pos_initial.x << ", " << pos_initial.y << ", " << pos_initial.z << ") m"); |
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INFO("Initial velocity: (" << vel_initial.x << ", " << vel_initial.y << ", " << vel_initial.z << ") m/s"); |
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OrbitalElements final_elements = propagate_orbital_elements(craft->orbit, period_seconds, earth->mass); |
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Vec3 pos_final; |
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Vec3 vel_final; |
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orbital_elements_to_cartesian(final_elements, earth->mass, &pos_final, &vel_final); |
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INFO("Final position: (" << pos_final.x << ", " << pos_final.y << ", " << pos_final.z << ") m"); |
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INFO("Final velocity: (" << vel_final.x << ", " << vel_final.y << ", " << vel_final.z << ") m/s"); |
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double pos_error = vec3_distance(pos_initial, pos_final); |
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double vel_error = vec3_distance(vel_initial, vel_final); |
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INFO("Position error after one period: " << pos_error << " m"); |
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INFO("Velocity error after one period: " << vel_error << " m/s"); |
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double r_initial = vec3_magnitude(pos_initial); |
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double r_final = vec3_magnitude(pos_final); |
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double relative_pos_error = pos_error / r_initial * 100.0; |
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double v_initial = vec3_magnitude(vel_initial); |
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double v_final = vec3_magnitude(vel_final); |
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double relative_vel_error = vel_error / v_initial * 100.0; |
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INFO("Relative position error: " << relative_pos_error << "%"); |
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INFO("Relative velocity error: " << relative_vel_error << "%"); |
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REQUIRE(relative_pos_error < 0.1); |
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REQUIRE(relative_vel_error < 0.1); |
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destroy_simulation(sim); |
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} |
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TEST_CASE("True anomaly accuracy after full orbit", "[analytical][propagation][true_anomaly]") { |
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const double TIME_STEP = 60.0; |
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SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP); |
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REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml")); |
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Spacecraft* craft = &sim->spacecraft[0]; |
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CelestialBody* earth = &sim->bodies[0]; |
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double initial_true_anomaly = craft->orbit.true_anomaly; |
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INFO("Initial true anomaly: " << initial_true_anomaly << " rad (" << initial_true_anomaly * 180.0 / M_PI << "°)"); |
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double a = craft->orbit.semi_major_axis; |
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double mu = G * earth->mass; |
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double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu); |
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OrbitalElements final_elements = propagate_orbital_elements(craft->orbit, period_seconds, earth->mass); |
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double final_true_anomaly = final_elements.true_anomaly; |
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INFO("Final true anomaly: " << final_true_anomaly << " rad (" << final_true_anomaly * 180.0 / M_PI << "°)"); |
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double expected_true_anomaly = fmod(initial_true_anomaly + 2.0 * M_PI, 2.0 * M_PI); |
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double anomaly_error = fabs(final_true_anomaly - expected_true_anomaly); |
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INFO("Expected true anomaly: " << expected_true_anomaly << " rad"); |
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INFO("True anomaly error: " << anomaly_error << " rad (" << anomaly_error * 180.0 / M_PI << "°)"); |
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REQUIRE(anomaly_error < 1.0e-6); |
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destroy_simulation(sim); |
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} |
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TEST_CASE("Vis-viva equation holds at multiple points in orbit", "[analytical][propagation][vis_viva]") { |
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const double TIME_STEP = 60.0; |
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SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP); |
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REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml")); |
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Spacecraft* craft = &sim->spacecraft[0]; |
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CelestialBody* earth = &sim->bodies[0]; |
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double a = craft->orbit.semi_major_axis; |
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double mu = G * earth->mass; |
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double true_anomalies[] = {0.0, M_PI / 4.0, M_PI / 2.0, 3.0 * M_PI / 4.0, M_PI}; |
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for (int i = 0; i < 5; i++) { |
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double nu = true_anomalies[i]; |
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INFO("Testing at true anomaly: " << nu << " rad (" << nu * 180.0 / M_PI << "°)"); |
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craft->orbit.true_anomaly = nu; |
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Vec3 position; |
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Vec3 velocity; |
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orbital_elements_to_cartesian(craft->orbit, earth->mass, &position, &velocity); |
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double r = vec3_magnitude(position); |
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double v = vec3_magnitude(velocity); |
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double expected_v_squared = mu * (2.0 / r - 1.0 / a); |
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double expected_v = sqrt(expected_v_squared); |
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double v_error = fabs(v - expected_v); |
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double relative_error = v_error / expected_v * 100.0; |
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INFO(" Radius: " << r << " m"); |
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INFO(" Actual velocity: " << v << " m/s"); |
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INFO(" Expected velocity: " << expected_v << " m/s"); |
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INFO(" Error: " << v_error << " m/s (" << relative_error << "%)"); |
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REQUIRE(relative_error < 0.01); |
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} |
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destroy_simulation(sim); |
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} |
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TEST_CASE("Large timestep - dt greater than orbital period", "[analytical][timestep][large]") { |
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const double TIME_STEP = 60.0; |
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SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP); |
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REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml")); |
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Spacecraft* craft = &sim->spacecraft[1]; |
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CelestialBody* earth = &sim->bodies[0]; |
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double a = craft->orbit.semi_major_axis; |
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double mu = G * earth->mass; |
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double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu); |
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INFO("Orbital period: " << period_seconds << " s (" << period_seconds / 3600.0 << " hours)"); |
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double large_dt = period_seconds * 2.0; |
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INFO("Timestep: " << large_dt << " s (2x orbital period)"); |
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Vec3 pos_before; |
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Vec3 vel_before; |
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orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_before, &vel_before); |
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OrbitalElements propagated = propagate_orbital_elements(craft->orbit, large_dt, earth->mass); |
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Vec3 pos_after; |
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Vec3 vel_after; |
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orbital_elements_to_cartesian(propagated, earth->mass, &pos_after, &vel_after); |
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double r_before = vec3_magnitude(pos_before); |
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double r_after = vec3_magnitude(pos_after); |
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double v_before = vec3_magnitude(vel_before); |
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double v_after = vec3_magnitude(vel_after); |
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INFO("Before propagation:"); |
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INFO(" Radius: " << r_before << " m"); |
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INFO(" Velocity: " << v_before << " m/s"); |
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INFO("After 2 periods:"); |
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INFO(" Radius: " << r_after << " m"); |
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INFO(" Velocity: " << v_after << " m/s"); |
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double r_error = fabs(r_after - r_before); |
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double v_error = fabs(v_after - v_before); |
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double relative_r_error = r_error / r_before * 100.0; |
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double relative_v_error = v_error / v_before * 100.0; |
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INFO("Radius error: " << r_error << " m (" << relative_r_error << "%)"); |
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INFO("Velocity error: " << v_error << " m/s (" << relative_v_error << "%)"); |
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REQUIRE(relative_r_error < 0.1); |
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REQUIRE(relative_v_error < 0.1); |
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destroy_simulation(sim); |
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} |
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TEST_CASE("Very small timestep - dt less than 1 second", "[analytical][timestep][small]") { |
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const double TIME_STEP = 60.0; |
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SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP); |
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REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml")); |
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Spacecraft* craft = &sim->spacecraft[1]; |
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CelestialBody* earth = &sim->bodies[0]; |
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Vec3 pos_before; |
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Vec3 vel_before; |
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orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_before, &vel_before); |
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double small_dt = 0.1; |
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INFO("Timestep: " << small_dt << " s"); |
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OrbitalElements propagated = propagate_orbital_elements(craft->orbit, small_dt, earth->mass); |
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Vec3 pos_after; |
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Vec3 vel_after; |
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orbital_elements_to_cartesian(propagated, earth->mass, &pos_after, &vel_after); |
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double pos_change = vec3_distance(pos_before, pos_after); |
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double vel_change = vec3_distance(vel_before, vel_after); |
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INFO("Position change: " << pos_change << " m"); |
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INFO("Velocity change: " << vel_change << " m/s"); |
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double v_before_mag = vec3_magnitude(vel_before); |
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double expected_pos_change = v_before_mag * small_dt; |
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double pos_error = fabs(pos_change - expected_pos_change); |
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INFO("Expected position change (v·dt): " << expected_pos_change << " m"); |
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INFO("Position error: " << pos_error << " m"); |
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INFO("Relative position error: " << (pos_error / expected_pos_change * 100.0) << "%"); |
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REQUIRE(pos_error < VELOCITY_TOLERANCE_TIMESTEP * small_dt * 10.0); |
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REQUIRE(vel_change < VELOCITY_TOLERANCE_TIMESTEP); |
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destroy_simulation(sim); |
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} |
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TEST_CASE("Accuracy vs timestep size relationship", "[analytical][timestep][accuracy]") { |
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const double TIME_STEP = 60.0; |
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SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP); |
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REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml")); |
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Spacecraft* craft = &sim->spacecraft[1]; |
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CelestialBody* earth = &sim->bodies[0]; |
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double a = craft->orbit.semi_major_axis; |
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double mu = G * earth->mass; |
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double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu); |
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double dt_ratios[] = {0.01, 0.1, 1.0, 10.0}; |
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Vec3 pos_initial; |
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Vec3 vel_initial; |
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orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_initial, &vel_initial); |
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for (int i = 0; i < 4; i++) { |
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double dt = period_seconds * dt_ratios[i]; |
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INFO("Testing dt = " << dt << " s (" << dt_ratios[i] << "x period)"); |
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OrbitalElements propagated = propagate_orbital_elements(craft->orbit, dt, earth->mass); |
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Vec3 pos_final; |
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Vec3 vel_final; |
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orbital_elements_to_cartesian(propagated, earth->mass, &pos_final, &vel_final); |
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double pos_error = vec3_distance(pos_initial, pos_final); |
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double vel_error = vec3_distance(vel_initial, vel_final); |
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double num_periods = dt / period_seconds; |
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double expected_num_orbits = round(num_periods); |
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double fractional_phase = num_periods - expected_num_orbits; |
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double expected_pos_error = fractional_phase * 2.0 * M_PI * a; |
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INFO(" Position error: " << pos_error << " m"); |
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INFO(" Expected error (phase): " << expected_pos_error << " m"); |
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INFO(" Number of periods: " << num_periods); |
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if (expected_num_orbits > 0 && expected_pos_error > 1.0e-6) { |
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double relative_error = pos_error / expected_pos_error; |
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INFO(" Relative error: " << relative_error); |
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REQUIRE(relative_error < 0.5); |
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} else if (expected_num_orbits > 0) { |
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INFO(" Expected error is zero, skipping relative error check"); |
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REQUIRE(pos_error < 1.0e-3); |
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} |
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} |
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destroy_simulation(sim); |
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} |
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TEST_CASE("Mean anomaly accumulation over long propagation", "[analytical][timestep][accumulation]") { |
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const double TIME_STEP = 60.0; |
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SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP); |
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REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml")); |
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Spacecraft* craft = &sim->spacecraft[1]; |
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CelestialBody* earth = &sim->bodies[0]; |
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double a = craft->orbit.semi_major_axis; |
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double mu = G * earth->mass; |
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double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu); |
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double mean_motion = sqrt(mu / pow(a, 3.0)); |
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double initial_true_anomaly = craft->orbit.true_anomaly; |
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INFO("Initial true anomaly: " << initial_true_anomaly << " rad"); |
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double propagation_time = period_seconds * 100.0; |
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INFO("Propagation time: " << propagation_time << " s (" << propagation_time / period_seconds << " periods)"); |
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OrbitalElements propagated = propagate_orbital_elements(craft->orbit, propagation_time, earth->mass); |
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double final_true_anomaly = propagated.true_anomaly; |
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INFO("Final true anomaly: " << final_true_anomaly << " rad"); |
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double expected_delta_anomaly = mean_motion * propagation_time; |
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double expected_final_anomaly = fmod(initial_true_anomaly + expected_delta_anomaly, 2.0 * M_PI); |
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|
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INFO("Expected final anomaly: " << expected_final_anomaly << " rad"); |
||||
|
||||
double raw_error = fabs(final_true_anomaly - expected_final_anomaly); |
||||
double anomaly_error = fmin(raw_error, 2.0 * M_PI - raw_error); |
||||
|
||||
INFO("True anomaly error: " << anomaly_error << " rad (" << anomaly_error * 180.0 / M_PI << "°)"); |
||||
|
||||
REQUIRE(anomaly_error < 1.0e-3); |
||||
|
||||
destroy_simulation(sim); |
||||
} |
||||
@ -1,41 +0,0 @@
|
||||
# Test Configuration: Analytical Propagation Tests |
||||
# Combined configuration for apsides and timestep testing |
||||
# Contains two spacecraft with different orbital parameters |
||||
|
||||
[[bodies]] |
||||
name = "Earth" |
||||
mass = 5.972e24 |
||||
radius = 6.371e6 |
||||
parent_index = -1 |
||||
color = { r = 0.0, g = 0.5, b = 1.0 } |
||||
orbit = { |
||||
semi_major_axis = 0.0, |
||||
eccentricity = 0.0, |
||||
true_anomaly = 0.0 |
||||
} |
||||
|
||||
[[spacecraft]] |
||||
name = "Apsides_Test_Spacecraft" |
||||
mass = 1000.0 |
||||
parent_index = 0 |
||||
orbit = { |
||||
semi_major_axis = 2.0e7, |
||||
eccentricity = 0.6, |
||||
true_anomaly = 0.0, |
||||
inclination = 0.0, |
||||
longitude_of_ascending_node = 0.0, |
||||
argument_of_periapsis = 0.0 |
||||
} |
||||
|
||||
[[spacecraft]] |
||||
name = "Timestep_Test_Spacecraft" |
||||
mass = 1000.0 |
||||
parent_index = 0 |
||||
orbit = { |
||||
semi_major_axis = 1.5e7, |
||||
eccentricity = 0.4, |
||||
true_anomaly = 0.0, |
||||
inclination = 0.0, |
||||
longitude_of_ascending_node = 0.0, |
||||
argument_of_periapsis = 0.0 |
||||
} |
||||
Loading…
Reference in new issue