Rewrite technical documentation

- Updated technical_reference.md to reflect analytical propagation - Added docs/config_format.md with complete TOML format reference - Added docs/coding_standards.md with coding conventions - Simplified technical reference (removed ASCII diagrams, verbose sections)
5 months ago · a458fa8d96
5 changed files with 1393 additions and 471 deletions
--- a/docs/coding_standards.md
+++ b/docs/coding_standards.md
@ -0,0 +1,343 @@
+# Coding Standards - Orbital Mechanics Simulation
+
+## Code Style
+
+- **C-style C++**: structs and functions only, NO classes or templates
+- **File extensions**: Use `.cpp` extensions for all source files (for future C++ features if needed)
+- **Include guards**: All headers use include guards (e.g., `#ifndef MODULE_NAME_H`)
+- **Function design**: Small, focused functions with single responsibilities
+
+```cpp
+// Header file with include guard
+#ifndef ORBITAL_MECHANICS_H
+#define ORBITAL_MECHANICS_H
+
+struct OrbitalElements {
+    double semi_major_axis;
+    double eccentricity;
+    double true_anomaly;
+};
+
+OrbitalElements propagate_orbital_elements(OrbitalElements elements, double dt, double parent_mass);
+
+#endif
+```
+
+## Naming Conventions
+
+**Struct names**: PascalCase
+```cpp
+struct CelestialBody { };
+struct OrbitalElements { };
+struct Spacecraft { };
+```
+
+**Function names**: snake_case
+```cpp
+propagate_orbital_elements()
+find_dominant_body()
+update_bodies_physics()
+```
+
+**Member variables**: snake_case
+```cpp
+global_position
+local_velocity
+parent_index
+```
+
+**Constants**: UPPER_CASE
+```cpp
+PARABOLIC_TOLERANCE
+MIN_MASS_RATIO
+```
+
+**Enum values**: UPPER_CASE with prefix
+```cpp
+enum BurnDirection { BURN_PROGRADE, BURN_RETROGRADE };
+enum TriggerType { TRIGGER_TIME, TRIGGER_TRUE_ANOMALY };
+```
+
+## Comments
+
+- **Minimal comments**: Code should be self-documenting
+- **Non-obvious logic only**: Comment only what cannot be inferred from the code
+- **No decorative blocks**: No `===`, `---`, or ASCII art comment blocks
+
+```cpp
+// Good: minimal comments
+if (vec3_distance(pos, parent_pos) > soi_radius) {
+    return 0;
+}
+
+// Bad: excessive decoration
+// ========================================
+// SOI Check Function
+// ========================================
+// This function checks if we're in SOI
+// ========================================
+```
+
+## Whitespace
+
+- **No trailing whitespace**: All files (including markdown) must not have trailing whitespace
+- **Pre-commit hook**: Automatically strips trailing whitespace
+- **Markdown line breaks**: Use `<br>` tag instead of two trailing spaces
+
+```markdown
+Good:
+Line 1<br>
+Line 2
+
+Bad:
+Line 2
+Line 4
+```
+
+## Memory Management
+
+- **Dynamic arrays**: Use `malloc` and `free`
+- **Struct-based design**: No RAII or smart pointers
+- **Manual cleanup**: Destroy functions handle cleanup
+
+```cpp
+// Allocation
+SimulationState* sim = malloc(sizeof(SimulationState));
+sim->bodies = malloc(max_bodies * sizeof(CelestialBody));
+
+// Cleanup
+void destroy_simulation(SimulationState* sim) {
+    free(sim->bodies);
+    free(sim->spacecraft);
+    free(sim);
+}
+```
+
+## Code Organization
+
+**Layer separation**: Physics, Simulation, Configuration, Rendering layers
+
+**Physics module independence**: Physics functions use parameter-based signatures, no dependencies on simulation structures
+
+```cpp
+// Good: parameter-based, independent
+Vec3 vec3_add(Vec3 a, Vec3 b);
+Mat3 mat3_rotation_orbital(double omega, double i, double omega_upper);
+
+// Avoid: depends on specific structures
+Vec3 compute_global_position(CelestialBody* body);  // Simulation layer
+```
+
+**Headers vs implementation**:
+- Headers (`.h`): Declarations only
+- Implementation (`.cpp`): Function definitions
+
+## Floating-Point Comparisons (Testing)
+
+- **Use `WithinAbs()`**: Required for floating-point comparisons
+- **Avoid `Approx()`**: Deprecated in Catch2
+- **Required header**: `<catch2/matchers/catch_matchers_floating_point.hpp>`
+
+```cpp
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+
+TEST_CASE("orbital energy conservation") {
+    double energy = calculate_total_energy(sim);
+    REQUIRE_THAT(energy, WithinAbs(expected, 1e-6));
+}
+```
+
+## Git Workflow
+
+- **Small commits**: Logical separation of changes
+- **Concise messages**: One-line commit messages preferred
+- **Build before commit**: Run `make && make test` before committing
+
+```bash
+# Verify build and tests pass
+make && make test
+
+# Commit with descriptive message
+git add .
+git commit -m "add parabolic orbit propagation"
+```
+
+## Build System
+
+**Makefile targets**:
+- `make` or `make all`: Build simulation
+- `make test`: Build and run automated tests
+- `make clean`: Remove build artifacts
+- `make rebuild`: Clean and rebuild
+
+**Default configuration**:
+- Time step: 60 seconds for solar system scale
+- Physics steps per frame: 100 (default)
+- Simulation time per frame: 60s × 100 = 6000 seconds at 1× speed
+
+```bash
+# Full build
+make
+
+# Run tests
+make test
+
+# Clean and rebuild
+make rebuild
+```
+
+## Physics Considerations
+
+**Time step**: 60 seconds for solar system scale
+
+**Circular orbit velocity**:
+```cpp
+v = sqrt(G * M / r)
+```
+
+**Sphere of Influence (SOI)**: Hill sphere approximation
+```cpp
+r_soi = a * (m / M)^(2/5)
+```
+
+**SOI transitions**: 0.5× distance hysteresis to prevent oscillation
+
+**Parabolic orbits**: Escape velocity
+```cpp
+v² = 2GM / r
+```
+
+**Hyperbolic orbits**: Positive total energy with asymptotic velocity at infinity
+
+**Analytical propagation**: Uses Kepler equation solvers (not RK4 integration)
+- Elliptical: E - e·sin(E) = M
+- Parabolic: D + D³/3 = M (Barker's equation)
+- Hyperbolic: H - e·sinh(H) = M
+
+## Module Dependencies
+
+```
+Physics (foundation, no dependencies)
+    ↓
+Orbital Mechanics (depends only on Physics)
+    ↓
+Spacecraft, Maneuver (depend on Physics)
+    ↓
+Simulation (depends on Physics, Orbital Mechanics, Spacecraft, Maneuver)
+    ↓
+Config Loader (depends on Simulation)
+Config Validator (depends on Simulation and Orbital Mechanics)
+Renderer (depends on Simulation)
+UI Renderer (depends on Renderer and Simulation)
+```
+
+**Key principles**:
+- Physics is completely independent
+- Lower layers never depend on upper layers
+- Each module has clear, minimal dependencies
+
+## Testing Guidelines
+
+- **Framework**: Catch2
+- **Run tests**: `make test`
+- **Test configs**: Located in `tests/configs/`
+- **Descriptive names**: Use clear test case names
+
+```bash
+# Run all tests
+make test
+
+# Run specific test config
+./orbit_test '[config_name]'
+
+# Test with debug output (shows INFO messages)
+./orbit_test -s '[config_name]'
+```
+
+**Test structure**:
+```cpp
+TEST_CASE("elliptical orbit energy conservation", "[energy]") {
+    SimulationState* sim = create_simulation(10, 1, 0, 60.0);
+    load_system_config(sim, "tests/configs/elliptical.toml");
+
+    double initial_energy = calculate_system_total_energy(sim);
+
+    for (int i = 0; i < 100; i++) {
+        update_simulation(sim);
+    }
+
+    double final_energy = calculate_system_total_energy(sim);
+    REQUIRE_THAT(final_energy, WithinAbs(initial_energy, 1e-6));
+
+    destroy_simulation(sim);
+}
+```
+
+## Common Patterns
+
+**Struct initialization**:
+```cpp
+CelestialBody earth = {0};
+strcpy(earth.name, "Earth");
+earth.mass = 5.972e24;
+earth.radius = 6.371e6;
+```
+
+**Error handling**: Return codes or NULL pointers
+```cpp
+int result = some_function();
+if (result != 0) {
+    return result;
+}
+
+CelestialBody* body = find_body(sim, "Earth");
+if (body == NULL) {
+    return -1;
+}
+```
+
+**Const correctness**: Use `const` for read-only parameters
+```cpp
+Vec3 vec3_add(const Vec3 a, const Vec3 b) {
+    Vec3 result = { a.x + b.x, a.y + b.y, a.z + b.z };
+    return result;
+}
+```
+
+## File Organization
+
+**Directory structure**:
+```
+src/
+  physics.h/cpp
+  orbital_mechanics.h/cpp
+  simulation.h/cpp
+  spacecraft.h/cpp
+  maneuver.h/cpp
+  config_loader.h/cpp
+  config_validator.h/cpp
+  renderer.h/cpp
+  ui_renderer.h/cpp
+  test_utilities.h/cpp
+
+tests/
+  test_*.cpp
+  configs/
+
+configs/
+  *.toml
+
+docs/
+  *.md
+```
+
+## Pre-commit Hooks
+
+The project uses a pre-commit hook that:
+- Strips trailing whitespace from all files
+- Prevents commits with trailing whitespace
+
+**If you see a "trailing whitespace" error**:
+1. The hook has automatically fixed the files
+2. Review the changes
+3. Stage them again and retry the commit
--- a/docs/config_format.md
+++ b/docs/config_format.md
@ -0,0 +1,490 @@
+# Config Format Reference
+
+## Overview
+
+Simulation configuration files use TOML format and are loaded via `load_system_config()` in config_loader.h. The config defines three main sections:
+
+- `[[bodies]]` - Celestial bodies (stars, planets, moons)
+- `[[spacecraft]]` - Spacecraft orbiting bodies
+- `[[maneuvers]]` - Impulsive burns for spacecraft
+
+## Bodies Configuration
+
+Each body entry defines a celestial object with physical properties and orbital elements.
+
+### Required Fields
+
+| Field | Type | Units | Description |
+|-------|------|-------|-------------|
+| `name` | string | - | Unique identifier for the body |
+| `mass` | float | kg | Mass of the body |
+| `radius` | float | m | Physical radius of the body |
+| `parent_index` | integer | - | Index of parent body (-1 for root/star) |
+| `color` | table | RGB | RGB color for rendering |
+
+### Orbit Table (nested)
+
+| Field | Type | Units | Default | Description |
+|-------|------|-------|---------|-------------|
+| `semi_major_axis` | float | m | 0.0 | Semi-major axis (elliptical/hyperbolic orbits only) |
+| `semi_latus_rectum` | float | m | - | Semi-latus rectum (parabolic orbits only) |
+| `eccentricity` | float | - | 0.0 | Orbital eccentricity (0-1 for elliptical, ~1 for parabolic, >1 for hyperbolic) |
+| `true_anomaly` | float | rad | 0.0 | Initial true anomaly (position along orbit) |
+| `inclination` | float | rad | 0.0 | Orbital plane inclination |
+| `longitude_of_ascending_node` | float | rad | 0.0 | Longitude of ascending node |
+| `argument_of_periapsis` | float | rad | 0.0 | Argument of periapsis |
+
+### Bodies Example
+
+```toml
+# Root body (star)
+[[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
+}
+
+# Planet orbiting the star
+[[bodies]]
+name = "Earth"
+mass = 5.972e24
+radius = 6.371e6
+parent_index = 0
+color = { r = 0.0, g = 0.5, b = 1.0 }
+orbit = {
+    semi_major_axis = 1.496e11,
+    eccentricity = 0.0167,
+    inclination = 0.0,
+    longitude_of_ascending_node = 0.0,
+    argument_of_periapsis = 0.0,
+    true_anomaly = 0.0
+}
+
+# Moon orbiting the planet
+[[bodies]]
+name = "Moon"
+mass = 7.342e22
+radius = 1.737e6
+parent_index = 1
+color = { r = 0.7, g = 0.7, b = 0.7 }
+orbit = {
+    semi_major_axis = 3.844e8,
+    eccentricity = 0.0549,
+    inclination = 0.089,
+    true_anomaly = 0.0
+}
+```
+
+### Special Cases
+
+**Root Bodies:** Set `parent_index = -1`. Root bodies represent stars and have no parent. Their orbital elements should all be zero.
+
+**Parabolic Orbits:** When eccentricity ≈ 1.0 (within `PARABOLIC_TOLERANCE = 1e-3`), use `semi_latus_rectum` instead of `semi_major_axis`:
+```toml
+[[bodies]]
+name = "Comet"
+mass = 1.0e14
+radius = 5.0e3
+parent_index = 0
+color = { r = 0.7, g = 0.8, b = 0.9 }
+orbit = {
+    semi_latus_rectum = 2.992e11,
+    eccentricity = 1.0,
+    true_anomaly = 0.0
+}
+```
+
+**Hyperbolic Orbits:** Use negative `semi_major_axis` for hyperbolic trajectories:
+```toml
+[[bodies]]
+name = "InterstellarComet"
+mass = 1.0e14
+radius = 5.0e3
+parent_index = 0
+color = { r = 0.5, g = 1.0, b = 0.5 }
+orbit = {
+    semi_major_axis = -1.496e11,
+    eccentricity = 1.5,
+    true_anomaly = 0.0
+}
+```
+
+**3D Orbital Orientation:** Use inclination, longitude_of_ascending_node, and argument_of_periapsis for inclined orbits (Molniya example):
+```toml
+[[spacecraft]]
+name = "Molniya_Satellite"
+mass = 1000.0
+parent_index = 0
+orbit = {
+    semi_major_axis = 26540000.0,
+    eccentricity = 0.74,
+    true_anomaly = 0.0,
+    inclination = 1.107,
+    longitude_of_ascending_node = 0.0,
+    argument_of_periapsis = 4.71
+}
+```
+
+## Spacecraft Configuration
+
+Spacecraft are similar to bodies but lack physical radius and sphere of influence. They must orbit an existing body.
+
+### Required Fields
+
+| Field | Type | Units | Description |
+|-------|------|-------|-------------|
+| `name` | string | - | Unique identifier for the spacecraft |
+| `mass` | float | kg | Mass of the spacecraft |
+| `parent_index` | integer | - | Index of parent body (must reference a valid body) |
+
+### Orbit Table (nested)
+
+Same as bodies - see orbital elements table above.
+
+### Spacecraft Example
+
+```toml
+[[spacecraft]]
+name = "LEO_Satellite"
+mass = 1000.0
+parent_index = 1
+orbit = {
+    semi_major_axis = 6.771e6,
+    eccentricity = 0.0,
+    true_anomaly = 0.0
+}
+```
+
+### Differences from Bodies
+
+- No `radius` field
+- No `color` field
+- No sphere of influence (SOI)
+- `parent_index` must be a valid body index (cannot be -1)
+- Cannot be a parent to other bodies or spacecraft
+
+## Maneuvers Configuration
+
+Maneuvers define impulsive burns that modify spacecraft velocity. Each maneuver specifies when and how to execute a burn.
+
+### Required Fields
+
+| Field | Type | Units | Description |
+|-------|------|-------|-------------|
+| `name` | string | - | Unique identifier for the maneuver |
+| `spacecraft_name` | string | - | Name of the spacecraft to apply burn to |
+| `direction` | string | - | Burn direction (see valid values below) |
+| `delta_v` | float | m/s | Velocity change magnitude |
+| `trigger_type` | string | - | Trigger condition type |
+| `trigger_value` | float | varies | Trigger condition value |
+
+### Valid Direction Values
+
+| Direction | Description |
+|-----------|-------------|
+| `"prograde"` | Along velocity vector (increases orbital energy) |
+| `"retrograde"` | Opposite velocity vector (decreases orbital energy) |
+| `"normal"` | Along angular momentum vector (orbit normal) |
+| `"antinormal"` | Opposite angular momentum vector |
+| `"radial_in"` | Toward parent body |
+| `"radial_out"` | Away from parent body |
+
+### Valid Trigger Types
+
+| Trigger Type | trigger_value | Description |
+|--------------|----------------|-------------|
+| `"time"` | seconds | Execute when simulation time >= trigger_value |
+| `"true_anomaly"` | radians | Execute when spacecraft true anomaly within 0.01 rad of trigger_value |
+
+### Maneuvers Example
+
+```toml
+# Time-based burn at 1 hour
+[[maneuvers]]
+name = "orbit_raise_1"
+spacecraft_name = "LEO_Satellite"
+trigger_type = "time"
+trigger_value = 3600.0
+direction = "prograde"
+delta_v = 500.0
+
+# True anomaly-based burn at periapsis (ν = 0)
+[[maneuvers]]
+name = "periapsis_burn"
+spacecraft_name = "LEO_Satellite"
+trigger_type = "true_anomaly"
+trigger_value = 0.0
+direction = "prograde"
+delta_v = 1000.0
+
+# Retrograde burn at apogee for orbit circularization
+[[maneuvers]]
+name = "circularize"
+spacecraft_name = "LEO_Satellite"
+trigger_type = "true_anomaly"
+trigger_value = 3.14159
+direction = "retrograde"
+delta_v = 500.0
+```
+
+## Parsing Details
+
+### Parabolic vs Non-Parabolic Orbits
+
+The parser uses eccentricity to determine which orbit parameter is required:
+
+- **Parabolic (|e - 1.0| < 1e-3):** Requires `semi_latus_rectum`, `semi_major_axis` is ignored
+- **Non-parabolic (e ≠ 1.0):** Requires `semi_major_axis`, `semi_latus_rectum` is ignored
+
+### Default Values
+
+Orbital elements default to 0.0 if not specified:
+- `true_anomaly = 0.0`
+- `inclination = 0.0`
+- `longitude_of_ascending_node = 0.0`
+- `argument_of_periapsis = 0.0`
+
+### Parent Index Behavior
+
+The `parent_index` field defines orbital hierarchy:
+- `-1`: Root body (no parent, typically a star)
+- `0` to N: Index of parent body in the bodies array
+- Bodies must be ordered such that parents appear before children
+- Spacecraft `parent_index` must reference a valid body index
+
+### Numeric Type Handling
+
+All numeric fields accept either integers or floating-point values:
+- `mass`, `radius`, `semi_major_axis`, etc.: Accept int or float
+- `parent_index`: Accepts int (preferred) or float (converted to int)
+- Color components: Accept int or float (0-1 range typical)
+
+## Validation Rules
+
+The config validator (config_validator.cpp) runs automatically after loading. All validations must pass for the simulation to start.
+
+### Validation Constants
+
+| Constant | Value | Description |
+|----------|-------|-------------|
+| `MIN_MASS_RATIO` | 1000.0 | Minimum parent/child mass ratio for large bodies |
+| `PARABOLIC_TOLERANCE` | 1e-3 | Tolerance for detecting parabolic orbits |
+| `NESTED_ORBIT_FRACTION` | 5.0 | Max orbit radius as fraction of parent SOI |
+
+### Parent Index Ordering
+
+**Rule:** Body `parent_index` must be < body index or -1.
+
+**Purpose:** Ensures parents are defined before children in the config file.
+
+**Example Error:**
+```
+Body 'Moon' (index 3) has invalid parent_index 3 - must be < 3 or -1
+```
+
+**Spacecraft Validation:** Spacecraft `parent_index` must be a valid body index (0 to body_count-1).
+
+### Orbital Elements
+
+**Elliptical Orbits (e < 1):**
+- `semi_major_axis` must be > 0
+
+**Parabolic Orbits (|e - 1.0| < 1e-3):**
+- `semi_latus_rectum` must be > 0
+- `semi_major_axis` is not used
+
+**Hyperbolic Orbits (e > 1):**
+- `semi_major_axis` must be < 0 (negative for hyperbolic)
+- `semi_major_axis` must not be 0
+
+**General:**
+- `eccentricity` must be >= 0
+- `semi_major_axis` or `semi_latus_rectum` must not be 0
+
+### True Anomaly Ranges (Hyperbolic Orbits)
+
+**Rule:** For hyperbolic orbits (e > 1), true anomaly must be within valid asymptotic bounds.
+
+**Valid Range:** [0, arccos(-1/e)] ∪ [2π - arccos(-1/e), 2π]
+
+**Purpose:** Prevents specifying positions in the forbidden region of hyperbolic orbits.
+
+**Example Error:**
+```
+Spacecraft 'Test' has invalid true_anomaly for hyperbolic orbit
+  Eccentricity: 1.5000
+  True anomaly: 2.0000 rad
+  Valid range: [0, 2.3005] ∪ [3.9827, 2π]
+```
+
+### Initial Positions
+
+**Rule:** Distance between body and parent must exceed combined radii.
+
+**Purpose:** Prevents objects from starting inside their parent.
+
+**Example Error:**
+```
+Body 'Satellite' (index 2) too close to parent 'Earth' (index 1)
+  Distance: 6.37e6 m
+  Minimum required: 6.47e6 m (parent radius + body radius)
+```
+
+**Spacecraft:** Distance must be >= parent radius (spacecraft has no radius).
+
+### Mass Ratios
+
+**Rule:** For root children with radius > 50% of parent, mass ratio >= 1000.
+
+**Purpose:** Ensures hierarchical system stability for large bodies.
+
+**Example Error:**
+```
+Body 'LargeMoon' (mass=1.00e25 kg, radius=4.00e6 m) has insufficient mass ratio with root parent 'Earth' (mass=5.97e24 kg, radius=6.37e6 m)
+  Mass ratio: 0.60 (minimum required: 1000.00)
+  Radius ratio: 0.63 (triggers validation for radius > 50% of parent)
+```
+
+### SOI Overlap
+
+**Rule:** Bodies sharing the same parent must not have overlapping spheres of influence.
+
+**Purpose:** Prevents ambiguous SOI boundaries that could cause numerical instability.
+
+**Example Error:**
+```
+Bodies 'MoonA' and 'MoonB' have overlapping SOIs while sharing same parent 'Planet'
+  Separation: 1.00e8 m
+  Combined SOI: 1.50e8 m (7.00e7 + 8.00e7)
+  SOI overlap: 5.00e7 m
+```
+
+### Nested Orbits
+
+**Rule:** Moon-like bodies must orbit within 5x of parent's SOI.
+
+**Applies to:**
+- Bodies with radius < 30% of parent radius
+- Bodies with eccentricity < 0.5
+- Bodies with mass < 1e20 kg
+
+**Purpose:** Ensures moon orbits are stable within parent's sphere of influence.
+
+**Example Error:**
+```
+Body 'DistantMoon' orbit extends too far from parent 'Planet'
+  Child orbit radius: 2.00e9 m
+  Parent SOI radius: 1.00e9 m
+  Maximum allowed: 5.00e9 m (500.0% of parent SOI)
+```
+
+## Complete Example Config
+
+```toml
+# Complete Solar System Example with Spacecraft and Maneuvers
+
+[[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
+}
+
+[[bodies]]
+name = "Earth"
+mass = 5.972e24
+radius = 6.371e6
+parent_index = 0
+color = { r = 0.0, g = 0.5, b = 1.0 }
+orbit = {
+    semi_major_axis = 1.496e11,
+    eccentricity = 0.0167,
+    inclination = 0.0,
+    longitude_of_ascending_node = 0.0,
+    argument_of_periapsis = 0.0,
+    true_anomaly = 0.0
+}
+
+[[bodies]]
+name = "Moon"
+mass = 7.342e22
+radius = 1.737e6
+parent_index = 1
+color = { r = 0.7, g = 0.7, b = 0.7 }
+orbit = {
+    semi_major_axis = 3.844e8,
+    eccentricity = 0.0549,
+    inclination = 0.089,
+    true_anomaly = 0.0
+}
+
+[[spacecraft]]
+name = "LEO_Satellite"
+mass = 1000.0
+parent_index = 1
+orbit = {
+    semi_major_axis = 6.771e6,
+    eccentricity = 0.0,
+    true_anomaly = 0.0
+}
+
+[[spacecraft]]
+name = "Molniya_Satellite"
+mass = 1000.0
+parent_index = 1
+orbit = {
+    semi_major_axis = 26540000.0,
+    eccentricity = 0.74,
+    true_anomaly = 0.0,
+    inclination = 1.107,
+    longitude_of_ascending_node = 0.0,
+    argument_of_periapsis = 4.71
+}
+
+[[maneuvers]]
+name = "orbit_raise"
+spacecraft_name = "LEO_Satellite"
+trigger_type = "time"
+trigger_value = 3600.0
+direction = "prograde"
+delta_v = 500.0
+
+[[maneuvers]]
+name = "periapsis_burn"
+spacecraft_name = "Molniya_Satellite"
+trigger_type = "true_anomaly"
+trigger_value = 0.0
+direction = "prograde"
+delta_v = 1000.0
+```
+
+## Orbit Type Quick Reference
+
+| Eccentricity | Orbit Type | Parameter | Example |
+|--------------|------------|-----------|---------|
+| e = 0 | Circular | semi_major_axis | Planets, moons |
+| 0 < e < 1 | Elliptical | semi_major_axis (positive) | Typical satellites |
+| e ≈ 1 | Parabolic | semi_latus_rectum | Escape trajectories |
+| e > 1 | Hyperbolic | semi_major_axis (negative) | Interstellar objects |
+
+## Tips
+
+1. **Units:** Always use SI units (kg, meters, seconds, radians)
+2. **Angles:** Use radians for all angular values (inclination, true_anomaly, etc.)
+3. **Ordering:** List bodies from star -> planets -> moons in order
+4. **Testing:** Start with circular orbits (e=0) before adding complexity
+5. **Validation:** Read error messages carefully - they indicate specific violations
+6. **Precision:** Use scientific notation for large/small values (e.g., 1.496e11)
+7. **Colors:** Use RGB values in [0, 1] range for realistic rendering
+8. **Hyperbolic:** Remember true_anomaly limits for hyperbolic orbits
--- a/docs/planning/newton_raphson_propagation_plan.md
+++ b/docs/planning/newton_raphson_propagation_plan.md
--- a/docs/session_summaries/2026-02-04-documentation-rewrite.md
+++ b/docs/session_summaries/2026-02-04-documentation-rewrite.md
@ -0,0 +1,87 @@
+# Session Summary - Documentation Rewrite
+
+**Date:** 2026-02-04
+
+## Session Overview
+This session focused on rewriting the technical documentation to reflect the current state of the codebase after switching to analytical propagation.
+
+## Changes Made
+
+### 1. Explored codebase
+Used @explore sub-agent to identify all critical data structures and functions across the codebase.
+
+### 2. Created new technical reference
+Rewrote `docs/technical_reference.md` from scratch:
+- Updated all references from RK4 to analytical propagation
+- Added comprehensive data structure documentation with file locations
+- Added detailed function signatures for critical functions
+- Added module dependency graph (later removed)
+- Added analytical propagation algorithm details for all orbit types
+- Added velocity deviation detection (1e-6 tolerance)
+- Added orbital element reconstruction after burns and SOI transitions
+- Kept coordinate frame strategy, orbit types, and data flow sections
+- Initially had line numbers, ASCII diagrams (later removed)
+- Initial version: 730 lines
+
+### 3. Created config format documentation
+New file `docs/config_format.md`:
+- Complete TOML format documentation for bodies, spacecraft, maneuvers
+- All field descriptions, types, units
+- Parsing details and default values
+- All 7 validation rules with constants
+- Complete working example config
+- 490 lines
+
+### 4. Created coding standards documentation
+New file `docs/coding_standards.md`:
+- Code style (C-style C++, no classes/templates)
+- Naming conventions
+- Comment guidelines
+- Whitespace rules (no trailing whitespace)
+- Memory management (malloc/free)
+- Code organization and layer separation
+- Floating-point comparisons for tests
+- Git workflow
+- Build system details
+- Physics considerations
+- Module dependencies
+- Testing guidelines
+
+### 5. Simplified technical reference
+- Moved verbose config section to config_format.md (replaced with brief summary)
+- Moved config validator section to config_format.md (replaced with brief summary)
+- Removed most line numbers (kept only 5 critical algorithm locations)
+- Reduced from 655 lines to 557 lines
+
+### 6. Removed ASCII diagrams
+- Removed module dependency graph (replaced with text)
+- Removed data flow diagrams (replaced with text)
+- Removed SOI mechanics flow chart (replaced with text)
+- Reduced from 557 lines to 557 lines (text descriptions were concise)
+
+### 7. Cleaned up
+- Removed `docs/technical_reference.md.backup`
+
+## Commits
+No commits were made during this session (all documentation changes).
+
+## Results
+- Created 2 new documentation files (config_format.md, coding_standards.md)
+- Completely rewrote technical reference (730 lines → 557 lines)
+- Documentation is now LLM-friendly (text-only, no ASCII diagrams)
+- All content from original reference preserved, reorganized, and updated
+
+## Files Modified
+- `docs/technical_reference.md` - Completely rewritten
+- `docs/config_format.md` - Created (490 lines)
+- `docs/coding_standards.md` - Created
+- `docs/technical_reference.md.backup` - Removed
+
+## Next Steps
+None - documentation rewrite is complete.
+
+## Notes
+- Technical reference is now optimized for LLM agents to understand the codebase
+- Line numbers kept only for 5 critical algorithms (unlikely to change)
+- Detailed config format is in separate doc for easy reference
+- Coding standards are documented for consistency
--- a/docs/technical_reference.md
+++ b/docs/technical_reference.md