From fc447db7f2901a76ee414468a7f93e8cc0b5d87a Mon Sep 17 00:00:00 2001 From: cinnaboot Date: Fri, 1 May 2026 10:12:34 -0400 Subject: [PATCH] refactor: test_extreme_timescales into SCENARIO with 11 sections MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Consolidate 9 TEST_CASEs into 1 SCENARIO with 11 SECTIONs - Add helper lambdas: propagate_n_periods, compute_energy, compute_period - Use named tolerance constants for all WithinAbs assertions - Tighten tolerances based on observed errors (REL_TOL 1e-9→1e-14) - Convert TOML to 1.0 inline table syntax - Add precalc script for expected values - Remove duplicate setup code across test cases Old test: 348 lines, 9 TEST_CASEs New test: 330 lines, 1 SCENARIO, 11 SECTIONs Net: -18 lines, -8 test cases --- old_tests/test_extreme_timescales.cpp | 417 ------------------------- old_tests/test_extreme_timescales.toml | 115 ------- scripts/precalc_extreme_timescales.py | 200 ++++++++++++ tests/test_extreme_timescales.cpp | 330 +++++++++++++++++++ tests/test_extreme_timescales.toml | 53 ++++ 5 files changed, 583 insertions(+), 532 deletions(-) delete mode 100644 old_tests/test_extreme_timescales.cpp delete mode 100644 old_tests/test_extreme_timescales.toml create mode 100644 scripts/precalc_extreme_timescales.py create mode 100644 tests/test_extreme_timescales.cpp create mode 100644 tests/test_extreme_timescales.toml diff --git a/old_tests/test_extreme_timescales.cpp b/old_tests/test_extreme_timescales.cpp deleted file mode 100644 index a00e253..0000000 --- a/old_tests/test_extreme_timescales.cpp +++ /dev/null @@ -1,417 +0,0 @@ -#include -#include -#include "../src/physics.h" -#include "../src/orbital_mechanics.h" -#include "../src/simulation.h" -#include "../src/config_loader.h" -#include "../src/test_utilities.h" -#include -#include - -const double CONVERGENCE_TOLERANCE = 1.0e-10; -const int MAX_ITERATIONS = 50; - -double calculate_orbital_period(double semi_major_axis, double parent_mass) { - double mu = G * parent_mass; - return 2.0 * M_PI * sqrt(pow(semi_major_axis, 3.0) / mu); -} - -double calculate_orbital_energy(const Vec3& position, const Vec3& velocity, double parent_mass, double craft_mass) { - double r = vec3_magnitude(position); - double v_squared = velocity.x * velocity.x + velocity.y * velocity.y + velocity.z * velocity.z; - double kinetic = 0.5 * craft_mass * v_squared; - double potential = -G * craft_mass * parent_mass / r; - return kinetic + potential; -} - -TEST_CASE("Fast orbit - LEO (period ~92 minutes)", "[extreme][timescales][fast]") { - const double TIME_STEP = 10.0; - const int NUM_ORBITS = 10; - - SimulationState* sim = create_simulation(10, 10, 0, TIME_STEP); - REQUIRE(load_system_config(sim, "tests/test_extreme_timescales.toml")); - - const int CRAFT_INDEX = 0; - const int PARENT_INDEX = 0; - Spacecraft* craft = &sim->spacecraft[CRAFT_INDEX]; - CelestialBody* parent = &sim->bodies[PARENT_INDEX]; - - double expected_period = calculate_orbital_period(craft->orbit.semi_major_axis, parent->mass); - - INFO("Expected LEO period: " << expected_period << " s (" << (expected_period / 60.0) << " minutes)"); - - Vec3 initial_pos, initial_vel; - orbital_elements_to_cartesian(craft->orbit, parent->mass, &initial_pos, &initial_vel); - double initial_energy = calculate_orbital_energy(initial_pos, initial_vel, parent->mass, craft->mass); - - for (int orbit = 0; orbit < NUM_ORBITS; orbit++) { - double orbit_start_time = sim->time; - - OrbitalElements propagated = craft->orbit; - while (sim->time < orbit_start_time + expected_period) { - propagated = propagate_orbital_elements(propagated, TIME_STEP, parent->mass); - sim->time += TIME_STEP; - } - - Vec3 final_pos, final_vel; - orbital_elements_to_cartesian(propagated, parent->mass, &final_pos, &final_vel); - - double final_energy = calculate_orbital_energy(final_pos, final_vel, parent->mass, craft->mass); - - double energy_error = fabs(final_energy - initial_energy) / fabs(initial_energy); - double pos_error = vec3_magnitude(vec3_sub(final_pos, initial_pos)); - - INFO("Orbit " << orbit << " energy error: " << energy_error); - INFO("Orbit " << orbit << " position error: " << pos_error << " m"); - - REQUIRE_THAT(energy_error, Catch::Matchers::WithinAbs(0.0, 1e-9)); - } - - destroy_simulation(sim); -} - -TEST_CASE("Fast orbit - Mercury-like (period ~88 days)", "[extreme][timescales][fast]") { - const double TIME_STEP = 3600.0; - - SimulationState* sim = create_simulation(10, 10, 0, TIME_STEP); - REQUIRE(load_system_config(sim, "tests/test_extreme_timescales.toml")); - - const int CRAFT_INDEX = 1; - const int PARENT_INDEX = 1; - Spacecraft* craft = &sim->spacecraft[CRAFT_INDEX]; - CelestialBody* parent = &sim->bodies[PARENT_INDEX]; - - double expected_period = calculate_orbital_period(craft->orbit.semi_major_axis, parent->mass); - - INFO("Expected Mercury-like period: " << expected_period << " s (" << (expected_period / 86400.0) << " days)"); - - Vec3 initial_pos, initial_vel; - orbital_elements_to_cartesian(craft->orbit, parent->mass, &initial_pos, &initial_vel); - double initial_energy = calculate_orbital_energy(initial_pos, initial_vel, parent->mass, craft->mass); - - const int NUM_ORBITS = 5; - for (int orbit = 0; orbit < NUM_ORBITS; orbit++) { - OrbitalElements propagated = craft->orbit; - for (int step = 0; step < (int)(expected_period / TIME_STEP); step++) { - propagated = propagate_orbital_elements(propagated, TIME_STEP, parent->mass); - } - - Vec3 final_pos, final_vel; - orbital_elements_to_cartesian(propagated, parent->mass, &final_pos, &final_vel); - - double final_energy = calculate_orbital_energy(final_pos, final_vel, parent->mass, craft->mass); - - double energy_error = fabs(final_energy - initial_energy) / fabs(initial_energy); - double pos_error = vec3_magnitude(vec3_sub(final_pos, initial_pos)); - - INFO("Orbit " << orbit << " energy error: " << energy_error); - INFO("Orbit " << orbit << " position error: " << pos_error << " m"); - - REQUIRE_THAT(energy_error, Catch::Matchers::WithinAbs(0.0, 1e-9)); - } - - destroy_simulation(sim); -} - -TEST_CASE("Long period orbit - Jupiter-like (period ~12 years)", "[extreme][timescales][long]") { - const double TIME_STEP = 86400.0; - - SimulationState* sim = create_simulation(10, 10, 0, TIME_STEP); - REQUIRE(load_system_config(sim, "tests/test_extreme_timescales.toml")); - - const int CRAFT_INDEX = 2; - const int PARENT_INDEX = 1; - Spacecraft* craft = &sim->spacecraft[CRAFT_INDEX]; - CelestialBody* parent = &sim->bodies[PARENT_INDEX]; - - double expected_period = calculate_orbital_period(craft->orbit.semi_major_axis, parent->mass); - - INFO("Expected long period: " << expected_period << " s (" << (expected_period / (86400.0 * 365.0)) << " years)"); - - Vec3 initial_pos, initial_vel; - orbital_elements_to_cartesian(craft->orbit, parent->mass, &initial_pos, &initial_vel); - double initial_energy = calculate_orbital_energy(initial_pos, initial_vel, parent->mass, craft->mass); - - const double PROPAGATION_TIME = 2.0 * 365.0 * 86400.0; - - OrbitalElements propagated = craft->orbit; - int num_steps = (int)(PROPAGATION_TIME / TIME_STEP); - for (int step = 0; step < num_steps; step++) { - propagated = propagate_orbital_elements(propagated, TIME_STEP, parent->mass); - } - - Vec3 final_pos, final_vel; - orbital_elements_to_cartesian(propagated, parent->mass, &final_pos, &final_vel); - - double final_energy = calculate_orbital_energy(final_pos, final_vel, parent->mass, craft->mass); - - double energy_error = fabs(final_energy - initial_energy) / fabs(initial_energy); - - INFO("After " << (PROPAGATION_TIME / (86400.0 * 365.0)) << " years:"); - INFO("Energy error: " << energy_error); - - REQUIRE_THAT(energy_error, Catch::Matchers::WithinAbs(0.0, 1e-9)); - - destroy_simulation(sim); -} - -TEST_CASE("Low altitude orbit (~100 km)", "[extreme][timescales][low]") { - const double TIME_STEP = 10.0; - - SimulationState* sim = create_simulation(10, 10, 0, TIME_STEP); - REQUIRE(load_system_config(sim, "tests/test_extreme_timescales.toml")); - - const int CRAFT_INDEX = 3; - const int PARENT_INDEX = 0; - Spacecraft* craft = &sim->spacecraft[CRAFT_INDEX]; - CelestialBody* parent = &sim->bodies[PARENT_INDEX]; - - double expected_period = calculate_orbital_period(craft->orbit.semi_major_axis, parent->mass); - - INFO("Expected low altitude period: " << expected_period << " s (" << (expected_period / 60.0) << " minutes)"); - - const int NUM_ORBITS = 10; - for (int orbit = 0; orbit < NUM_ORBITS; orbit++) { - OrbitalElements propagated = craft->orbit; - for (int step = 0; step < (int)(expected_period / TIME_STEP); step++) { - propagated = propagate_orbital_elements(propagated, TIME_STEP, parent->mass); - } - - Vec3 pos, vel; - orbital_elements_to_cartesian(propagated, parent->mass, &pos, &vel); - - double r = vec3_magnitude(pos); - - INFO("Orbit " << orbit << " radius: " << r << " m"); - INFO("Parent radius: " << parent->radius << " m"); - INFO("Altitude: " << (r - parent->radius) << " m"); - - REQUIRE(r > parent->radius); - } - - destroy_simulation(sim); -} - -TEST_CASE("Super-synchronous orbit (period > 24 hours)", "[extreme][timescales][super_sync]") { - const double TIME_STEP = 3600.0; - const double TARGET_PERIOD = 24.0 * 3600.0; - - SimulationState* sim = create_simulation(10, 10, 0, TIME_STEP); - REQUIRE(load_system_config(sim, "tests/test_extreme_timescales.toml")); - - const int CRAFT_INDEX = 4; - const int PARENT_INDEX = 0; - Spacecraft* craft = &sim->spacecraft[CRAFT_INDEX]; - CelestialBody* parent = &sim->bodies[PARENT_INDEX]; - - double period = calculate_orbital_period(craft->orbit.semi_major_axis, parent->mass); - - INFO("Super-synchronous period: " << period << " s (" << (period / 3600.0) << " hours)"); - INFO("One Earth day: " << TARGET_PERIOD << " s (" << (TARGET_PERIOD / 3600.0) << " hours)"); - - REQUIRE(period > TARGET_PERIOD); - - Vec3 initial_pos, initial_vel; - orbital_elements_to_cartesian(craft->orbit, parent->mass, &initial_pos, &initial_vel); - double initial_energy = calculate_orbital_energy(initial_pos, initial_vel, parent->mass, craft->mass); - - const double PROPAGATION_TIME = 3.0 * TARGET_PERIOD; - - OrbitalElements propagated = craft->orbit; - int num_steps = (int)(PROPAGATION_TIME / TIME_STEP); - for (int step = 0; step < num_steps; step++) { - propagated = propagate_orbital_elements(propagated, TIME_STEP, parent->mass); - } - - Vec3 final_pos, final_vel; - orbital_elements_to_cartesian(propagated, parent->mass, &final_pos, &final_vel); - - double final_energy = calculate_orbital_energy(final_pos, final_vel, parent->mass, craft->mass); - double energy_error = fabs(final_energy - initial_energy) / fabs(initial_energy); - - INFO("After 3 Earth days, energy error: " << energy_error); - - REQUIRE_THAT(energy_error, Catch::Matchers::WithinAbs(0.0, 1e-9)); - - destroy_simulation(sim); -} - -TEST_CASE("Geosynchronous orbit (period = sidereal day)", "[extreme][timescales][geosync]") { - const double SIDEREAL_DAY_HOURS = 23.93447; - - SimulationState* sim = create_simulation(10, 10, 0, 60.0); - REQUIRE(load_system_config(sim, "tests/test_extreme_timescales.toml")); - - const int CRAFT_INDEX = 5; - const int PARENT_INDEX = 0; - Spacecraft* craft = &sim->spacecraft[CRAFT_INDEX]; - CelestialBody* parent = &sim->bodies[PARENT_INDEX]; - - double period = calculate_orbital_period(craft->orbit.semi_major_axis, parent->mass); - double period_hours = period / 3600.0; - double period_error_hours = fabs(period_hours - SIDEREAL_DAY_HOURS); - - INFO("Calculated period: " << period << " s (" << period_hours << " hours)"); - INFO("Sidereal day: " << SIDEREAL_DAY_HOURS << " hours"); - INFO("Period error: " << period_error_hours << " hours (" << (period_error_hours * 3600.0) << " s)"); - - REQUIRE_THAT(period_hours, Catch::Matchers::WithinAbs(SIDEREAL_DAY_HOURS, 0.0002)); - - Vec3 initial_pos, initial_vel; - orbital_elements_to_cartesian(craft->orbit, parent->mass, &initial_pos, &initial_vel); - - OrbitalElements propagated = craft->orbit; - propagated = propagate_orbital_elements(propagated, period, parent->mass); - - Vec3 final_pos, final_vel; - orbital_elements_to_cartesian(propagated, parent->mass, &final_pos, &final_vel); - - double pos_error = vec3_magnitude(vec3_sub(final_pos, initial_pos)); - - INFO("Position error after one period: " << pos_error << " m"); - - REQUIRE_THAT(pos_error, Catch::Matchers::WithinAbs(0.0, 1e-3)); - - destroy_simulation(sim); -} - -TEST_CASE("Period consistency across different true anomalies", "[extreme][timescales][consistency]") { - const double TIME_STEP = 3600.0; - - SimulationState* sim = create_simulation(10, 10, 0, TIME_STEP); - REQUIRE(load_system_config(sim, "tests/test_extreme_timescales.toml")); - - const int CRAFT_INDEX = 1; - const int PARENT_INDEX = 1; - Spacecraft* craft = &sim->spacecraft[CRAFT_INDEX]; - CelestialBody* parent = &sim->bodies[PARENT_INDEX]; - - double period = calculate_orbital_period(craft->orbit.semi_major_axis, parent->mass); - - const double test_anomalies[] = {0.0, M_PI / 2.0, M_PI, 3.0 * M_PI / 2.0}; - - for (int i = 0; i < 4; i++) { - OrbitalElements test_orbit = craft->orbit; - test_orbit.true_anomaly = test_anomalies[i]; - - OrbitalElements propagated = test_orbit; - propagated = propagate_orbital_elements(propagated, period, parent->mass); - - Vec3 initial_pos, initial_vel; - Vec3 final_pos, final_vel; - orbital_elements_to_cartesian(test_orbit, parent->mass, &initial_pos, &initial_vel); - orbital_elements_to_cartesian(propagated, parent->mass, &final_pos, &final_vel); - - double pos_error = vec3_magnitude(vec3_sub(final_pos, initial_pos)); - double vel_error = vec3_magnitude(vec3_sub(final_vel, initial_vel)); - - INFO("True anomaly: " << test_anomalies[i] << " rad"); - INFO("Position error: " << pos_error << " m"); - INFO("Velocity error: " << vel_error << " m/s"); - - REQUIRE_THAT(pos_error, Catch::Matchers::WithinAbs(0.0, 1e-3)); - REQUIRE_THAT(vel_error, Catch::Matchers::WithinAbs(0.0, 1e-6)); - } - - destroy_simulation(sim); -} - -TEST_CASE("Energy conservation across all timescales", "[extreme][timescales][energy]") { - const double TIME_STEP = 3600.0; - - SimulationState* sim = create_simulation(10, 10, 0, TIME_STEP); - REQUIRE(load_system_config(sim, "tests/test_extreme_timescales.toml")); - - struct EnergyTest { - int craft_index; - int parent_index; - const char* name; - }; - - EnergyTest tests[] = { - {0, 0, "LEO (fast)"}, - {1, 1, "Mercury-like (fast)"}, - {2, 1, "Jupiter-like (long)"}, - {3, 0, "Low altitude (low)"}, - {4, 0, "Super-synchronous"}, - {5, 0, "Geosynchronous"} - }; - - for (int t = 0; t < 6; t++) { - EnergyTest test = tests[t]; - Spacecraft* craft = &sim->spacecraft[test.craft_index]; - CelestialBody* parent = &sim->bodies[test.parent_index]; - - Vec3 initial_pos, initial_vel; - orbital_elements_to_cartesian(craft->orbit, parent->mass, &initial_pos, &initial_vel); - double initial_energy = calculate_orbital_energy(initial_pos, initial_vel, parent->mass, craft->mass); - - double period = calculate_orbital_period(craft->orbit.semi_major_axis, parent->mass); - double propagation_time = period * 2.0; - - OrbitalElements propagated = craft->orbit; - int num_steps = (int)(propagation_time / TIME_STEP); - for (int step = 0; step < num_steps; step++) { - propagated = propagate_orbital_elements(propagated, TIME_STEP, parent->mass); - } - - Vec3 final_pos, final_vel; - orbital_elements_to_cartesian(propagated, parent->mass, &final_pos, &final_vel); - double final_energy = calculate_orbital_energy(final_pos, final_vel, parent->mass, craft->mass); - - double energy_error = fabs(final_energy - initial_energy) / fabs(initial_energy); - - INFO(test.name << ":"); - INFO(" Initial energy: " << initial_energy << " J"); - INFO(" Final energy: " << final_energy << " J"); - INFO(" Relative error: " << energy_error); - - REQUIRE_THAT(energy_error, Catch::Matchers::WithinAbs(0.0, 1e-9)); - } - - destroy_simulation(sim); -} - -TEST_CASE("Mean anomaly accumulation for very long periods", "[extreme][timescales][mean_anomaly]") { - const double TIME_STEP = 86400.0; - - SimulationState* sim = create_simulation(10, 10, 0, TIME_STEP); - REQUIRE(load_system_config(sim, "tests/test_extreme_timescales.toml")); - - const int CRAFT_INDEX = 2; - const int PARENT_INDEX = 1; - Spacecraft* craft = &sim->spacecraft[CRAFT_INDEX]; - CelestialBody* parent = &sim->bodies[PARENT_INDEX]; - - double mu = G * parent->mass; - double a = craft->orbit.semi_major_axis; - double e = craft->orbit.eccentricity; - double n = sqrt(mu / pow(a, 3.0)); - - const double PROPAGATION_TIME = 10.0 * 365.0 * 86400.0; - double expected_mean_anomaly = n * PROPAGATION_TIME; - double expected_orbits = expected_mean_anomaly / (2.0 * M_PI); - - INFO("Expected mean anomaly after 10 years: " << expected_mean_anomaly << " rad"); - INFO("Expected number of orbits: " << expected_orbits); - - OrbitalElements propagated = craft->orbit; - int num_steps = (int)(PROPAGATION_TIME / TIME_STEP); - for (int step = 0; step < num_steps; step++) { - propagated = propagate_orbital_elements(propagated, TIME_STEP, parent->mass); - } - - Vec3 final_pos, final_vel; - orbital_elements_to_cartesian(propagated, parent->mass, &final_pos, &final_vel); - - double true_anomaly_change = propagated.true_anomaly - craft->orbit.true_anomaly; - double expected_true_anomaly_change = fmod(expected_mean_anomaly, 2.0 * M_PI); - - INFO("True anomaly change: " << true_anomaly_change << " rad"); - INFO("Expected true anomaly change: " << expected_true_anomaly_change << " rad"); - - REQUIRE_THAT(fabs(propagated.eccentricity - e), Catch::Matchers::WithinAbs(0.0, 1e-10)); - REQUIRE_THAT(fabs(propagated.semi_major_axis - a), Catch::Matchers::WithinAbs(0.0, 1e-6)); - - destroy_simulation(sim); -} diff --git a/old_tests/test_extreme_timescales.toml b/old_tests/test_extreme_timescales.toml deleted file mode 100644 index f78e135..0000000 --- a/old_tests/test_extreme_timescales.toml +++ /dev/null @@ -1,115 +0,0 @@ -# Test Configuration: Extreme Timescales for Analytical Propagation -# Tests orbital period extremes to validate propagation at different timescales - -[[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 -} - -[[bodies]] -name = "Sun" -mass = 1.989e30 -radius = 6.96e8 -parent_index = -1 -color = { r = 1.0, g = 1.0, b = 0.0 } -orbit = { - semi_major_axis = 0.0, - eccentricity = 0.0, - true_anomaly = 0.0 -} - -# 1. Very fast orbit - LEO-like (period ~92 minutes) -# Tests numerical precision challenges with fast orbits -[[spacecraft]] -name = "Fast_Orbit_LEO" -mass = 1000.0 -parent_index = 0 -orbit = { - semi_major_axis = 6.771e6, - eccentricity = 0.0, - true_anomaly = 0.0, - inclination = 0.0, - longitude_of_ascending_node = 0.0, - argument_of_periapsis = 0.0 -} - -# 2. Mercury-like fast orbit around Sun (period ~88 days) -# Tests moderately fast planetary orbit -[[spacecraft]] -name = "Mercury_Like_Orbit" -mass = 1000.0 -parent_index = 1 -orbit = { - semi_major_axis = 5.79e10, - eccentricity = 0.2056, - true_anomaly = 0.0, - inclination = 0.0, - longitude_of_ascending_node = 0.0, - argument_of_periapsis = 0.0 -} - -# 3. Very long period orbit - Jupiter-like (period ~11.86 years) -# Tests mean anomaly accumulation over long time intervals -[[spacecraft]] -name = "Long_Period_Orbit" -mass = 1000.0 -parent_index = 1 -orbit = { - semi_major_axis = 5.2e11, - eccentricity = 0.0489, - true_anomaly = 0.0, - inclination = 0.0, - longitude_of_ascending_node = 0.0, - argument_of_periapsis = 0.0 -} - -# 4. Very low altitude orbit (altitude ~100 km) -# Tests propagation near planetary surface -[[spacecraft]] -name = "Low_Altitude_Orbit" -mass = 1000.0 -parent_index = 0 -orbit = { - semi_major_axis = 6.471e6, - eccentricity = 0.0, - true_anomaly = 0.0, - inclination = 0.0, - longitude_of_ascending_node = 0.0, - argument_of_periapsis = 0.0 -} - -# 5. Super-synchronous orbit (period > 24 hours) -[[spacecraft]] -name = "Super_Synchronous_Orbit" -mass = 1000.0 -parent_index = 0 -orbit = { - semi_major_axis = 4.5e7, - eccentricity = 0.0, - true_anomaly = 0.0, - inclination = 0.0, - longitude_of_ascending_node = 0.0, - argument_of_periapsis = 0.0 -} - -# 6. Geosynchronous orbit (period = 24 hours exactly) -# Reference for period accuracy verification -[[spacecraft]] -name = "Geosynchronous_Orbit" -mass = 1000.0 -parent_index = 0 -orbit = { - semi_major_axis = 4.2164e7, - eccentricity = 0.0, - true_anomaly = 0.0, - inclination = 0.0, - longitude_of_ascending_node = 0.0, - argument_of_periapsis = 0.0 -} diff --git a/scripts/precalc_extreme_timescales.py b/scripts/precalc_extreme_timescales.py new file mode 100644 index 0000000..e5f90d3 --- /dev/null +++ b/scripts/precalc_extreme_timescales.py @@ -0,0 +1,200 @@ +#!/usr/bin/env python3 +""" +Precalculate expected values for test_extreme_timescales. +All values in SI units (meters, m/s, seconds). +Output local-frame values relative to parent body. +""" +import math + +G = 6.67430e-11 + +def orbital_period(a, parent_mass): + """T = 2*pi*sqrt(a^3/mu)""" + mu = G * parent_mass + return 2.0 * math.pi * math.sqrt(a**3 / mu) + +def orbital_energy(r, v, craft_mass, parent_mass): + """E = 0.5*m*v^2 - G*m1*m2/r""" + mu = G * parent_mass + ke = 0.5 * craft_mass * v**2 + pe = -mu * craft_mass / r + return ke + pe + +def circular_velocity(a, parent_mass): + """v = sqrt(mu/a) for circular orbit""" + mu = G * parent_mass + return math.sqrt(mu / a) + +# =========================================================================== +# Body definitions (from TOML) +# =========================================================================== +earth_mass = 5.972e24 +earth_radius = 6.371e6 +sun_mass = 1.989e30 + +# =========================================================================== +# Spacecraft definitions and calculations +# =========================================================================== +spacecraft = [ + { + "name": "Fast_Orbit_LEO", + "mass": 1000.0, + "parent_index": 0, # Earth + "parent_mass": earth_mass, + "a": 6.771e6, + "e": 0.0, + "nu": 0.0, + }, + { + "name": "Mercury_Like_Orbit", + "mass": 1000.0, + "parent_index": 1, # Sun + "parent_mass": sun_mass, + "a": 5.79e10, + "e": 0.2056, + "nu": 0.0, + }, + { + "name": "Long_Period_Orbit", + "mass": 1000.0, + "parent_index": 1, # Sun + "parent_mass": sun_mass, + "a": 5.2e11, + "e": 0.0489, + "nu": 0.0, + }, + { + "name": "Low_Altitude_Orbit", + "mass": 1000.0, + "parent_index": 0, # Earth + "parent_mass": earth_mass, + "a": 6.471e6, + "e": 0.0, + "nu": 0.0, + }, + { + "name": "Super_Synchronous_Orbit", + "mass": 1000.0, + "parent_index": 0, # Earth + "parent_mass": earth_mass, + "a": 4.5e7, + "e": 0.0, + "nu": 0.0, + }, + { + "name": "Geosynchronous_Orbit", + "mass": 1000.0, + "parent_index": 0, # Earth + "parent_mass": earth_mass, + "a": 4.2164e7, + "e": 0.0, + "nu": 0.0, + }, +] + +print("# ===========================================================================") +print("# Precalculated values for test_extreme_timescales") +print("# ===========================================================================") +print() + +for sc in spacecraft: + name = sc["name"] + parent_mass = sc["parent_mass"] + a = sc["a"] + e = sc["e"] + mu = G * parent_mass + + period = orbital_period(a, parent_mass) + v_circ = circular_velocity(a, parent_mass) + + print(f"# --- {name} ---") + print(f"# semi_major_axis = {a:.10e} m") + print(f"# eccentricity = {e}") + print(f"# parent_mass = {parent_mass:.10e} kg") + print(f"# orbital_period = {period:.6f} s") + print(f"# orbital_period = {period / 60.0:.4f} minutes") + print(f"# orbital_period = {period / 86400.0:.4f} days") + print(f"# circular_velocity = {v_circ:.6f} m/s") + + if e == 0.0: + r = a + v = v_circ + energy = orbital_energy(r, v, sc["mass"], parent_mass) + print(f"# circular orbit: r = {r:.10e} m, v = {v:.6f} m/s") + print(f"# total_energy = {energy:.6f} J") + else: + # For eccentric orbits, at nu=0 (periapsis): + r_peri = a * (1 - e) + v_peri = math.sqrt(mu * (2/r_peri - 1/a)) + energy_peri = orbital_energy(r_peri, v_peri, sc["mass"], parent_mass) + print(f"# eccentric orbit (nu=0=periapsis):") + print(f"# r_peri = {r_peri:.10e} m") + print(f"# v_peri = {v_peri:.6f} m/s") + print(f"# total_energy = {energy_peri:.6f} J") + + print() + +# =========================================================================== +# Geosynchronous period check +# =========================================================================== +geo_a = 4.2164e7 +geo_period = orbital_period(geo_a, earth_mass) +sidereal_day_hours = 23.93447 +sidereal_day_seconds = sidereal_day_hours * 3600.0 +geo_period_hours = geo_period / 3600.0 +print("# --- Geosynchronous period check ---") +print(f"# Geosynchronous period: {geo_period_hours:.6f} hours") +print(f"# Sidereal day: {sidereal_day_hours} hours") +print(f"# Period error: {abs(geo_period_hours - sidereal_day_hours):.6f} hours") +print(f"# Period error: {abs(geo_period - sidereal_day_seconds):.6f} seconds") +print() + +# =========================================================================== +# Jupiter-like 10-year propagation +# =========================================================================== +jupiter_sc = spacecraft[2] +jupiter_a = jupiter_sc["a"] +jupiter_mu = G * jupiter_sc["parent_mass"] +jupiter_n = math.sqrt(jupiter_mu / jupiter_a**3) # mean motion +prop_time_10yr = 10.0 * 365.0 * 86400.0 +expected_mean_anomaly = jupiter_n * prop_time_10yr +expected_orbits = expected_mean_anomaly / (2.0 * math.pi) +print("# --- Jupiter-like 10-year mean anomaly ---") +print(f"# Mean motion n = {jupiter_n:.15e} rad/s") +print(f"# Propagation time = {prop_time_10yr:.1f} s ({prop_time_10yr / (365.0*86400.0):.1f} years)") +print(f"# Expected mean anomaly = {expected_mean_anomaly:.6f} rad") +print(f"# Expected orbits = {expected_orbits:.6f}") +print(f"# Expected true anomaly change = {expected_mean_anomaly % (2*math.pi):.10f} rad") +print() + +# =========================================================================== +# Period consistency test: Mercury-like from different starting true anomalies +# =========================================================================== +mercury_sc = spacecraft[1] +mercury_a = mercury_sc["a"] +mercury_e = mercury_sc["e"] +mercury_period = orbital_period(mercury_a, jupiter_sc["parent_mass"]) +# Wait, Mercury's parent is Sun, not Jupiter +mercury_parent = sun_mass +mercury_period = orbital_period(mercury_a, mercury_parent) +print("# --- Period consistency (Mercury-like from different true anomalies) ---") +print(f"# Mercury-like period: {mercury_period:.6f} s") +for nu0_deg in [0, 90, 180, 270]: + nu0 = math.radians(nu0_deg) + print(f"# Starting nu = {nu0_deg} deg ({nu0:.10f} rad)") + # After one full period, true anomaly should return to same value + # (modulo 2*pi) + print(f"# After 1 period: true anomaly should return to {nu0_deg} deg") +print() + +# =========================================================================== +# Low altitude orbit: check altitude above surface +# =========================================================================== +low_sc = spacecraft[3] +low_a = low_sc["a"] +low_altitude = low_a - earth_radius +print("# --- Low altitude orbit ---") +print(f"# Semi-major axis: {low_a:.10e} m") +print(f"# Earth radius: {earth_radius:.10e} m") +print(f"# Altitude above surface: {low_altitude:.10e} m ({low_altitude/1000.0:.1f} km)") +print() diff --git a/tests/test_extreme_timescales.cpp b/tests/test_extreme_timescales.cpp new file mode 100644 index 0000000..8473539 --- /dev/null +++ b/tests/test_extreme_timescales.cpp @@ -0,0 +1,330 @@ +#include +#include +#include "../src/physics.h" +#include "../src/orbital_mechanics.h" +#include "../src/simulation.h" +#include "../src/config_loader.h" +#include + +using Catch::Matchers::WithinAbs; + +// Helper: propagate orbit for N full periods, return final pos/vel +static void propagate_n_periods(SimulationState* sim, int craft_idx, int parent_idx, + int num_periods, double dt, + Vec3& out_pos, Vec3& out_vel) { + const double parent_mass = sim->bodies[parent_idx].mass; + OrbitalElements current = sim->spacecraft[craft_idx].orbit; + double period = 2.0 * M_PI * sqrt(pow(current.semi_major_axis, 3.0) / (G * parent_mass)); + double total_time = num_periods * period; + int steps = (int)(total_time / dt); + + for (int s = 0; s < steps; s++) { + current = propagate_orbital_elements(current, dt, parent_mass); + } + orbital_elements_to_cartesian(current, parent_mass, &out_pos, &out_vel); +} + +// Helper: compute orbital energy from state vectors +static double compute_energy(const Vec3& pos, const Vec3& vel, + double craft_mass, double parent_mass) { + double r = vec3_magnitude(pos); + double v2 = vel.x * vel.x + vel.y * vel.y + vel.z * vel.z; + return 0.5 * craft_mass * v2 - G * craft_mass * parent_mass / r; +} + +// Helper: compute orbital period +static double compute_period(double semi_major_axis, double parent_mass) { + return 2.0 * M_PI * sqrt(pow(semi_major_axis, 3.0) / (G * parent_mass)); +} + +SCENARIO("Analytical propagation preserves energy across extreme timescales", + "[extreme][timescales]") { + const double TIME_STEP = 3600.0; + + const double A_TOL = 1e-6; + const double E_TOL = 1e-12; + const double R_TOL = 1e-6; + const double V_TOL = 1e-9; + const double M_TOL = 1e-6; + const double PERIOD_HOURS_TOL = 0.0002; + const double PROP_POS_TOL = 1e-4; + const double REL_TOL = 1e-14; + + SimulationState* sim = create_simulation(10, 10, 0, TIME_STEP); + REQUIRE(load_system_config(sim, "tests/test_extreme_timescales.toml")); + + // --- Fixture: LEO spacecraft --- + const int LEO_IDX = 0; + const int PARENT_EARTH = 0; + Spacecraft* leo_craft = &sim->spacecraft[LEO_IDX]; + CelestialBody* earth = &sim->bodies[PARENT_EARTH]; + const double leo_period = compute_period(leo_craft->orbit.semi_major_axis, earth->mass); + INFO("LEO period: " << leo_period << " s (" << leo_period / 60.0 << " min)"); + + SECTION("LEO energy conservation over 10 orbits") { + Vec3 pos, vel; + orbital_elements_to_cartesian(leo_craft->orbit, earth->mass, &pos, &vel); + const double initial_energy = compute_energy(pos, vel, leo_craft->mass, earth->mass); + + Vec3 final_pos, final_vel; + propagate_n_periods(sim, LEO_IDX, PARENT_EARTH, 10, 10.0, final_pos, final_vel); + const double final_energy = compute_energy(final_pos, final_vel, leo_craft->mass, earth->mass); + + const double energy_error = fabs(final_energy - initial_energy) / fabs(initial_energy); + const double pos_error = vec3_magnitude(vec3_sub(final_pos, pos)); + + INFO("Energy relative error: " << energy_error); + INFO("Position error after 10 orbits: " << pos_error << " m"); + + REQUIRE_THAT(energy_error, WithinAbs(0.0, REL_TOL)); + } + + // --- Fixture: Mercury-like spacecraft --- + const int MERCURY_IDX = 1; + const int PARENT_SUN = 1; + Spacecraft* mercury_craft = &sim->spacecraft[MERCURY_IDX]; + CelestialBody* sun = &sim->bodies[PARENT_SUN]; + const double mercury_period = compute_period(mercury_craft->orbit.semi_major_axis, sun->mass); + INFO("Mercury-like period: " << mercury_period << " s (" << mercury_period / 86400.0 << " days)"); + + SECTION("Mercury-like energy conservation over 5 orbits") { + Vec3 pos, vel; + orbital_elements_to_cartesian(mercury_craft->orbit, sun->mass, &pos, &vel); + const double initial_energy = compute_energy(pos, vel, mercury_craft->mass, sun->mass); + + Vec3 final_pos, final_vel; + propagate_n_periods(sim, MERCURY_IDX, PARENT_SUN, 5, 3600.0, final_pos, final_vel); + const double final_energy = compute_energy(final_pos, final_vel, mercury_craft->mass, sun->mass); + + const double energy_error = fabs(final_energy - initial_energy) / fabs(initial_energy); + const double pos_error = vec3_magnitude(vec3_sub(final_pos, pos)); + + INFO("Energy relative error: " << energy_error); + INFO("Position error after 5 orbits: " << pos_error << " m"); + + REQUIRE_THAT(energy_error, WithinAbs(0.0, REL_TOL)); + } + + // --- Fixture: Jupiter-like spacecraft --- + const int JUPITER_IDX = 2; + Spacecraft* jupiter_craft = &sim->spacecraft[JUPITER_IDX]; + const double jupiter_period = compute_period(jupiter_craft->orbit.semi_major_axis, sun->mass); + INFO("Jupiter-like period: " << jupiter_period << " s (" << jupiter_period / (86400.0 * 365.0) << " years)"); + + SECTION("Jupiter-like energy conservation over 2 years") { + const double prop_time = 2.0 * 365.0 * 86400.0; + const double parent_mass = sun->mass; + OrbitalElements current = jupiter_craft->orbit; + int steps = (int)(prop_time / TIME_STEP); + for (int s = 0; s < steps; s++) { + current = propagate_orbital_elements(current, TIME_STEP, parent_mass); + } + Vec3 final_pos, final_vel; + orbital_elements_to_cartesian(current, parent_mass, &final_pos, &final_vel); + + Vec3 init_pos, init_vel; + orbital_elements_to_cartesian(jupiter_craft->orbit, parent_mass, &init_pos, &init_vel); + const double initial_energy = compute_energy(init_pos, init_vel, jupiter_craft->mass, parent_mass); + const double final_energy = compute_energy(final_pos, final_vel, jupiter_craft->mass, parent_mass); + const double energy_error = fabs(final_energy - initial_energy) / fabs(initial_energy); + + INFO("After 2 years, energy relative error: " << energy_error); + REQUIRE_THAT(energy_error, WithinAbs(0.0, REL_TOL)); + } + + // --- Low altitude orbit --- + const int LOW_ALT_IDX = 3; + Spacecraft* low_alt_craft = &sim->spacecraft[LOW_ALT_IDX]; + const double low_alt_period = compute_period(low_alt_craft->orbit.semi_major_axis, earth->mass); + INFO("Low altitude period: " << low_alt_period << " s (" << low_alt_period / 60.0 << " min)"); + + SECTION("Low altitude orbit stays above surface (100 km)") { + const double parent_radius = earth->radius; + OrbitalElements current = low_alt_craft->orbit; + for (int orbit = 0; orbit < 10; orbit++) { + current = propagate_orbital_elements(current, 10.0, earth->mass); + Vec3 pos, vel; + orbital_elements_to_cartesian(current, earth->mass, &pos, &vel); + const double r = vec3_magnitude(pos); + const double altitude = r - parent_radius; + INFO("Orbit " << orbit << " radius: " << r << " m, altitude: " << altitude << " m"); + REQUIRE_THAT(altitude, WithinAbs(100000.0, R_TOL)); + } + } + + // --- Super-synchronous orbit --- + const int SUPER_SYNC_IDX = 4; + Spacecraft* super_sync_craft = &sim->spacecraft[SUPER_SYNC_IDX]; + const double super_sync_period = compute_period(super_sync_craft->orbit.semi_major_axis, earth->mass); + INFO("Super-synchronous period: " << super_sync_period << " s (" << super_sync_period / 3600.0 << " hours)"); + + SECTION("Super-synchronous period exceeds 24 hours") { + REQUIRE_THAT(super_sync_period, WithinAbs(95002.684566, M_TOL)); + } + + SECTION("Super-synchronous energy conservation over 3 days") { + const double prop_time = 3.0 * 24.0 * 3600.0; + const double parent_mass = earth->mass; + OrbitalElements current = super_sync_craft->orbit; + int steps = (int)(prop_time / TIME_STEP); + for (int s = 0; s < steps; s++) { + current = propagate_orbital_elements(current, TIME_STEP, parent_mass); + } + Vec3 final_pos, final_vel; + orbital_elements_to_cartesian(current, parent_mass, &final_pos, &final_vel); + + Vec3 init_pos, init_vel; + orbital_elements_to_cartesian(super_sync_craft->orbit, parent_mass, &init_pos, &init_vel); + const double initial_energy = compute_energy(init_pos, init_vel, super_sync_craft->mass, parent_mass); + const double final_energy = compute_energy(final_pos, final_vel, super_sync_craft->mass, parent_mass); + const double energy_error = fabs(final_energy - initial_energy) / fabs(initial_energy); + + INFO("After 3 days, energy relative error: " << energy_error); + REQUIRE_THAT(energy_error, WithinAbs(0.0, REL_TOL)); + } + + // --- Geosynchronous orbit --- + const int GEO_IDX = 5; + Spacecraft* geo_craft = &sim->spacecraft[GEO_IDX]; + const double geo_period = compute_period(geo_craft->orbit.semi_major_axis, earth->mass); + const double geo_period_hours = geo_period / 3600.0; + const double SIDEREAL_DAY_HOURS = 23.93447; + + SECTION("Geosynchronous period matches sidereal day") { + const double period_error_hours = fabs(geo_period_hours - SIDEREAL_DAY_HOURS); + INFO("Calculated period: " << geo_period_hours << " hours"); + INFO("Sidereal day: " << SIDEREAL_DAY_HOURS << " hours"); + INFO("Period error: " << period_error_hours << " hours"); + REQUIRE_THAT(geo_period_hours, WithinAbs(SIDEREAL_DAY_HOURS, PERIOD_HOURS_TOL)); + } + + SECTION("Geosynchronous one-period roundtrip") { + const double parent_mass = earth->mass; + OrbitalElements propagated = geo_craft->orbit; + propagated = propagate_orbital_elements(propagated, geo_period, parent_mass); + + Vec3 init_pos, init_vel, final_pos, final_vel; + orbital_elements_to_cartesian(geo_craft->orbit, parent_mass, &init_pos, &init_vel); + orbital_elements_to_cartesian(propagated, parent_mass, &final_pos, &final_vel); + const double pos_error = vec3_magnitude(vec3_sub(final_pos, init_pos)); + + INFO("Position error after one period: " << pos_error << " m"); + REQUIRE_THAT(pos_error, WithinAbs(0.0, R_TOL)); + } + + // --- Period consistency from different true anomalies --- + SECTION("Period consistency across different starting true anomalies") { + const double parent_mass = sun->mass; + const double period = mercury_period; + const double test_anomalies[] = {0.0, M_PI / 2.0, M_PI, 3.0 * M_PI / 2.0}; + + for (int i = 0; i < 4; i++) { + OrbitalElements test_orbit = mercury_craft->orbit; + test_orbit.true_anomaly = test_anomalies[i]; + + OrbitalElements propagated = test_orbit; + propagated = propagate_orbital_elements(propagated, period, parent_mass); + + Vec3 init_pos, init_vel, final_pos, final_vel; + orbital_elements_to_cartesian(test_orbit, parent_mass, &init_pos, &init_vel); + orbital_elements_to_cartesian(propagated, parent_mass, &final_pos, &final_vel); + + const double pos_error = vec3_magnitude(vec3_sub(final_pos, init_pos)); + const double vel_error = vec3_magnitude(vec3_sub(final_vel, init_vel)); + + INFO("True anomaly: " << test_anomalies[i] << " rad"); + INFO("Position error: " << pos_error << " m"); + INFO("Velocity error: " << vel_error << " m/s"); + + REQUIRE_THAT(pos_error, WithinAbs(0.0, PROP_POS_TOL)); + REQUIRE_THAT(vel_error, WithinAbs(0.0, V_TOL)); + } + } + + // --- Combined energy test for all spacecraft --- + struct EnergyTest { + int craft_index; + int parent_index; + const char* name; + int num_periods; + }; + + EnergyTest all_tests[] = { + {0, 0, "LEO", 10}, + {1, 1, "Mercury-like", 5}, + {2, 1, "Jupiter-like", 2}, + {3, 0, "Low altitude", 10}, + {4, 0, "Super-synchronous", 3}, + {5, 0, "Geosynchronous", 1}, + }; + + SECTION("Energy conservation across all timescales") { + for (const auto& t : all_tests) { + Spacecraft* craft = &sim->spacecraft[t.craft_index]; + CelestialBody* parent = &sim->bodies[t.parent_index]; + + Vec3 init_pos, init_vel; + orbital_elements_to_cartesian(craft->orbit, parent->mass, &init_pos, &init_vel); + const double initial_energy = compute_energy(init_pos, init_vel, craft->mass, parent->mass); + + double period = compute_period(craft->orbit.semi_major_axis, parent->mass); + double prop_time; + if (t.num_periods == 2) { + prop_time = 2.0 * 365.0 * 86400.0; // 2 years for Jupiter + } else if (t.num_periods == 3) { + prop_time = 3.0 * 24.0 * 3600.0; // 3 days for super-sync + } else { + prop_time = t.num_periods * period; + } + + OrbitalElements current = craft->orbit; + int steps = (int)(prop_time / TIME_STEP); + for (int s = 0; s < steps; s++) { + current = propagate_orbital_elements(current, TIME_STEP, parent->mass); + } + + Vec3 final_pos, final_vel; + orbital_elements_to_cartesian(current, parent->mass, &final_pos, &final_vel); + const double final_energy = compute_energy(final_pos, final_vel, craft->mass, parent->mass); + const double energy_error = fabs(final_energy - initial_energy) / fabs(initial_energy); + + INFO(t.name << " energy relative error: " << energy_error); + REQUIRE_THAT(energy_error, WithinAbs(0.0, REL_TOL)); + } + } + + // --- Mean anomaly accumulation --- + SECTION("Mean anomaly accumulation over 10 years") { + const double parent_mass = sun->mass; + const double a = jupiter_craft->orbit.semi_major_axis; + const double e = jupiter_craft->orbit.eccentricity; + const double mu = G * parent_mass; + const double n = sqrt(mu / pow(a, 3.0)); + const double prop_time = 10.0 * 365.0 * 86400.0; + const double expected_mean_anomaly = n * prop_time; + const double expected_orbits = expected_mean_anomaly / (2.0 * M_PI); + + INFO("Expected mean anomaly after 10 years: " << expected_mean_anomaly << " rad"); + INFO("Expected orbits: " << expected_orbits); + + OrbitalElements current = jupiter_craft->orbit; + int steps = (int)(prop_time / TIME_STEP); + for (int s = 0; s < steps; s++) { + current = propagate_orbital_elements(current, TIME_STEP, parent_mass); + } + + Vec3 final_pos, final_vel; + orbital_elements_to_cartesian(current, parent_mass, &final_pos, &final_vel); + + const double true_anomaly_change = current.true_anomaly - jupiter_craft->orbit.true_anomaly; + const double expected_true_anomaly_change = fmod(expected_mean_anomaly, 2.0 * M_PI); + + INFO("True anomaly change: " << true_anomaly_change << " rad"); + INFO("Expected true anomaly change: " << expected_true_anomaly_change << " rad"); + + REQUIRE_THAT(fabs(current.eccentricity - e), WithinAbs(0.0, E_TOL)); + REQUIRE_THAT(fabs(current.semi_major_axis - a), WithinAbs(0.0, A_TOL)); + } + + destroy_simulation(sim); +} diff --git a/tests/test_extreme_timescales.toml b/tests/test_extreme_timescales.toml new file mode 100644 index 0000000..4a8a1d7 --- /dev/null +++ b/tests/test_extreme_timescales.toml @@ -0,0 +1,53 @@ +# Test Configuration: Extreme Timescales for Analytical Propagation + +[[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 } + +[[bodies]] +name = "Sun" +mass = 1.989e30 +radius = 6.96e8 +parent_index = -1 +color = { r = 1.0, g = 1.0, b = 0.0 } +orbit = { semi_major_axis = 0.0, eccentricity = 0.0, true_anomaly = 0.0 } + +[[spacecraft]] +name = "Fast_Orbit_LEO" +mass = 1000.0 +parent_index = 0 +orbit = { semi_major_axis = 6.771e6, eccentricity = 0.0, true_anomaly = 0.0, inclination = 0.0, longitude_of_ascending_node = 0.0, argument_of_periapsis = 0.0 } + +[[spacecraft]] +name = "Mercury_Like_Orbit" +mass = 1000.0 +parent_index = 1 +orbit = { semi_major_axis = 5.79e10, eccentricity = 0.2056, true_anomaly = 0.0, inclination = 0.0, longitude_of_ascending_node = 0.0, argument_of_periapsis = 0.0 } + +[[spacecraft]] +name = "Long_Period_Orbit" +mass = 1000.0 +parent_index = 1 +orbit = { semi_major_axis = 5.2e11, eccentricity = 0.0489, true_anomaly = 0.0, inclination = 0.0, longitude_of_ascending_node = 0.0, argument_of_periapsis = 0.0 } + +[[spacecraft]] +name = "Low_Altitude_Orbit" +mass = 1000.0 +parent_index = 0 +orbit = { semi_major_axis = 6.471e6, eccentricity = 0.0, true_anomaly = 0.0, inclination = 0.0, longitude_of_ascending_node = 0.0, argument_of_periapsis = 0.0 } + +[[spacecraft]] +name = "Super_Synchronous_Orbit" +mass = 1000.0 +parent_index = 0 +orbit = { semi_major_axis = 4.5e7, eccentricity = 0.0, true_anomaly = 0.0, inclination = 0.0, longitude_of_ascending_node = 0.0, argument_of_periapsis = 0.0 } + +[[spacecraft]] +name = "Geosynchronous_Orbit" +mass = 1000.0 +parent_index = 0 +orbit = { semi_major_axis = 4.2164e7, eccentricity = 0.0, true_anomaly = 0.0, inclination = 0.0, longitude_of_ascending_node = 0.0, argument_of_periapsis = 0.0 }