From 4d10be19eea90a502927fe37a7353928beac147e Mon Sep 17 00:00:00 2001 From: cinnaboot Date: Tue, 20 Jan 2026 11:11:54 -0500 Subject: [PATCH] Update documentation with resolution status MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Updated docs to reflect that the spacecraft initialization bug has been resolved by config validation. docs/test_plan_invalid_parent_assignment.md: - Changed status from "Implementation phase" to "Complete (Tests 1-3 resolved)" - Updated bug diagnosis to show solution implemented - Updated all test cases with actual results (Tests 1-3: ✅ PASS, Test 4: ❌ FAIL) - Added implementation summary with commit references - Updated test matrix to show actual results - Updated future work section to reflect current status docs/mission_planning.md: - Marked FIXME as RESOLVED with solution details - Updated spacecraft parameters to show corrected position - Added note that delta-v issue remains pending - Updated "position/velocity" line to reflect current implementation Test Status: - Test 1 (Earth→Spacecraft parent switch): ✅ RESOLVED - Test 2 (Mass hierarchy): ✅ RESOLVED - Test 3 (Config validation): ✅ RESOLVED - Test 4 (Mutual SOI): ❌ PENDING (separate issue) --- docs/mission_planning.md | 26 +++- docs/test_plan_invalid_parent_assignment.md | 127 ++++++++++++++------ 2 files changed, 113 insertions(+), 40 deletions(-) diff --git a/docs/mission_planning.md b/docs/mission_planning.md index f3f1b28..42eb0de 100644 --- a/docs/mission_planning.md +++ b/docs/mission_planning.md @@ -122,7 +122,20 @@ Add Spacecraft body to config with placeholder position/velocity (set at runtime ### Problem: Incorrect Delta-V Direction After Multi-Day Wait -FIXME: while running this simulation config graphically, I noticed that a larger +**RESOLVED (Jan 20, 2026):** + +The FIXME issue below has been addressed by adding config validation in +`src/config_loader.cpp` that prevents bodies from starting too close to their +parent bodies. The spacecraft configuration has been corrected to use proper LEO +altitude (200km) instead of placeholder values. + +**Solution Applied:** +- Config validation: distance ≥ parent.radius + body.radius +- Spacecraft position corrected to 1.49606571e11 m (Earth + 6,571 km offset) +- Tests 1-3 in `test_invalid_parent_assignment.cpp` now pass + +**FIXME (Original Issue - RESOLVED):** + While running this simulation config graphically, I noticed that a larger problem is in simulation::find_dominant_body(). Earth's parent gets set to the satellite's index, which should never happen. I think the actual fix should be to have non-massive satellites in a different @@ -167,7 +180,11 @@ However, after 94 days: 3. Applies magnitude-based delta-v without considering spacecraft's actual velocity direction 4. Results in incorrect burn direction -### Solution Required +### Solution Required (Pending) + +NOTE: The immediate bug of Earth becoming a child of spacecraft has been +resolved by config validation. The delta-v calculation issue below remains for +future implementation. Modify `apply_transfer_burn()` to: @@ -250,14 +267,15 @@ Spacecraft may not enter Mars SOI due to: - Sun (index 0): Root body, 1.989e30 kg - Earth (index 1): 5.972e24 kg, 1.496e11 m from Sun - Mars (index 2): 6.39e23 kg, 2.279e11 m from Sun -- Spacecraft (index 3): 1.0 kg, parent=Earth (position/velocity set at runtime) +- Spacecraft (index 3): 1.0 kg, parent=Earth (position specified in config) **Spacecraft parameters:** - mass = 1.0 kg - radius = 1000.0 m - parent_index = 1 (Earth) - color = magenta (r=1.0, g=0.0, b=0.5) -- position/velocity: Placeholders (0,0,0) - set by `initialize_spacecraft_leo()` +- position: 1.49606571e11 m (Earth position + 6,571,000 m LEO offset) +- velocity: Calculated by `initialize_bodies()` using `semi_major_axis = 6.571e6` --- diff --git a/docs/test_plan_invalid_parent_assignment.md b/docs/test_plan_invalid_parent_assignment.md index d95b463..fd3397e 100644 --- a/docs/test_plan_invalid_parent_assignment.md +++ b/docs/test_plan_invalid_parent_assignment.md @@ -4,7 +4,7 @@ Comprehensive test suite to capture and validate parent-child relationship bugs in orbital mechanics simulation. **Date:** January 20, 2026 -**Status:** Implementation phase +**Status:** Complete (Tests 1-3 resolved) **Related:** `docs/mission_planning.md` FIXME section --- @@ -13,22 +13,35 @@ Comprehensive test suite to capture and validate parent-child relationship bugs ### Root Cause Identified -**The Bug:** In `tests/configs/earth_mars_simple.toml`, the spacecraft has placeholder values: +**The Bug (Fixed):** In `tests/configs/earth_mars_simple.toml`, spacecraft had placeholder values: - `position = {1.496e11, 0, 0}` (IDENTICAL to Earth) - `velocity = {0, 0, 0}` (zero velocity) - `SOI = ~17.3 meters` (calculated from mass=1kg) -**What Happens:** -1. Config loads with spacecraft at Earth's exact position +**What Happened:** +1. Config loaded with spacecraft at Earth's exact position 2. During `find_dominant_body(1)` for Earth: - - Checks all bodies - - Finds spacecraft at distance = 0 - - `0 < 17.3` is TRUE - - Sets Earth's parent to spacecraft! + - Checks all bodies + - Finds spacecraft at distance = 0 + - `0 < 17.3` is TRUE + - Sets Earth's parent to spacecraft! -**Why Test Works But GUI Fails:** +**Why Test Failed But GUI Failed Worse:** - Test calls `initialize_spacecraft_leo()` → spacecraft moved to proper LEO orbit (200km from Earth) -- GUI never calls this → placeholder values cause bug +- GUI never called this → placeholder values caused immediate bug + +### Solution Implemented + +**Config Validation in `src/config_loader.cpp`:** +- Added validation loop after parsing bodies, before `initialize_bodies()` +- Validates that distance between body and parent ≥ parent.radius + body.radius +- Provides clear error message with actual and required distances +- Prevents loading invalid configs with bodies too close to their parents + +**Config Fix in `tests/configs/earth_mars_simple.toml`:** +- Changed spacecraft position from `1.496e11` (same as Earth) to `1.49606571e11` +- This places spacecraft at proper LEO altitude: Earth position + 6,571,000 m +- 6,571 km = Earth radius (6,371 km) + 200 km altitude --- @@ -38,9 +51,13 @@ Comprehensive test suite to capture and validate parent-child relationship bugs **Purpose:** Directly detect when Earth's parent becomes spacecraft (the exact bug from FIXME) -**Expected Behavior:** -- Before fix: **FAILS** on step 0 or 1 -- After spacecraft fix: **PASSES** +**Actual Result:** ✅ **PASSES** + +**How It Was Fixed:** +- Config validation now rejects bodies starting at parent's position +- Spacecraft properly positioned at LEO altitude (6,571 km from Earth center) +- `find_dominant_body()` never finds spacecraft at distance=0 +- Earth's parent remains Sun throughout simulation **Config:** `tests/configs/earth_mars_simple.toml` @@ -55,9 +72,12 @@ REQUIRE(sim->bodies[EARTH_IDX].parent_index != SPACECRAFT_IDX); **Purpose:** Validate that massive bodies never become children of small bodies -**Expected Behavior:** -- Before fix: **FAILS** (mass hierarchy violations) -- After spacecraft fix: **PASSES** +**Actual Result:** ✅ **PASSES** + +**How It Was Fixed:** +- Config validation ensures proper parent-child distance +- Mass hierarchy preserved throughout simulation +- Earth never becomes child of spacecraft or other bodies **Config:** `tests/configs/earth_mars_simple.toml` @@ -83,15 +103,20 @@ if (child_mass > 1e20) { // Planet-scale **Purpose:** Detect invalid config initialization (bodies starting too close together) -**Expected Behavior:** -- Before fix: **FAILS** (distance ≈ 0 between Earth and spacecraft) -- After spacecraft fix: **PASSES** +**Actual Result:** ✅ **PASSES** + +**How It Was Fixed:** +- Test updated to use radius-based validation (matches config_loader logic) +- Spacecraft now at proper LEO position: 6,571,000 m from Earth center +- Validation: distance (6,571,000 m) ≥ Earth.radius + spacecraft.radius (6,372,000 m) +- Config validation catches any bodies positioned within parent's radius **Config:** `tests/configs/earth_mars_simple.toml` **Key Assertion:** ```cpp -REQUIRE(distance > 100000.0); // At least 100km separation +double min_distance = sim->bodies[EARTH_IDX].radius + sim->bodies[SPACECRAFT_IDX].radius; +REQUIRE(distance >= min_distance); // parent.radius + body.radius ``` --- @@ -100,19 +125,24 @@ REQUIRE(distance > 100000.0); // At least 100km separation **Purpose:** Edge case: two Earth-like planets positioned within each other's SOI -**Expected Behavior:** -- Before fix: **FAILS** (one planet becomes parent of the other) -- After spacecraft fix: **STILL FAILS** (separate issue) +**Actual Result:** ❌ **STILL FAILS** (separate issue, not fixed by spacecraft validation) **Config:** `tests/configs/mutual_soi_close.toml` **Setup:** - PlanetA: mass = 5.972e24 kg, position = {1.496e11, 0, 0} - PlanetB: mass = 5.972e24 kg, position = {1.501e11, 0, 0} -- Separation: 5e8 meters -- Planet SOI: ~9.24e8 meters +- Separation: 5e8 meters (500 million km) +- Planet SOI: ~9.25e8 meters (925 million km) - **Both planets within each other's SOI** +**Why This Fails:** +- Both planets start with parent=0 (Sun) +- Both are within each other's SOI +- `find_dominant_body()` logic selects closest body within SOI +- Result: PlanetA selects PlanetB as parent, PlanetB selects PlanetA as parent +- Config validation passes (both are ≥ parent.radius + body.radius from Sun) + **Key Assertions:** ```cpp // Both should orbit Sun (not each other) @@ -130,19 +160,19 @@ for (int parent : history.planet_b_parents) { **Expected Behavior (Option A):** - Both planets should continue orbiting Sun -- Neither should become the other's parent -- This requires future fix to `find_dominant_body()` logic +- Neither should become other's parent +- This requires future fix to `find_dominant_body()` logic (mass hierarchy check) --- ## Test Matrix -| Test Case | Config | Tests | Expected (Before Fix) | Expected (After Spacecraft Fix) | +| Test Case | Config | Tests | Expected (Before Fix) | **Actual Result** | |-----------|--------|-------|----------------------|--------------------------------| -| **1. Earth→Spacecraft** | earth_mars_simple.toml | Parent assignment | **FAIL** | **PASS** | -| **2. Mass Hierarchy** | earth_mars_simple.toml | Mass ratios | **FAIL** | **PASS** | -| **3. Config Validation** | earth_mars_simple.toml | Separation distance | **FAIL** | **PASS** | -| **4. Mutual SOI** | mutual_soi_close.toml | Edge case behavior | **FAIL** | **FAIL** (separate issue) | +| **1. Earth→Spacecraft** | earth_mars_simple.toml | Parent assignment | **FAIL** | **✅ PASS** | +| **2. Mass Hierarchy** | earth_mars_simple.toml | Mass ratios | **FAIL** | **✅ PASS** | +| **3. Config Validation** | earth_mars_simple.toml | Separation distance | **FAIL** | **✅ PASS** | +| **4. Mutual SOI** | mutual_soi_close.toml | Edge case behavior | **FAIL** | **❌ FAIL** (separate issue) | --- @@ -160,10 +190,29 @@ Add to CMakeLists.txt or Makefile test targets --- +## Implementation Summary + +**Solution Applied (Jan 20, 2026):** +1. **Config validation in `src/config_loader.cpp`**: + - Validates parent-child distances before initialization + - Requires distance ≥ parent.radius + body.radius + - Prevents loading invalid configs + +2. **Config fix in `tests/configs/earth_mars_simple.toml`**: + - Spacecraft position corrected to proper LEO altitude + - Position: 1.49606571e11 m (Earth position + 6,571,000 m offset) + - Velocity calculated by `initialize_bodies()` using `semi_major_axis = 6.571e6` + +3. **Test updates in `tests/test_invalid_parent_assignment.cpp`**: + - Test 3 updated to use radius-based validation + - Matches config_loader validation logic + +--- + ## Future Work -### After Spacecraft Fix -Tests 1-3 should pass. Test 4 will continue to fail, documenting a separate issue. +### Current Status +Tests 1-3 are now passing. Test 4 continues to fail, documenting a separate mutual SOI issue. ### Potential Fixes for Test 4 1. Add mass hierarchy check to `find_dominant_body()` @@ -179,7 +228,13 @@ Tests 1-3 should pass. Test 4 will continue to fail, documenting a separate issu --- ## References -- `docs/mission_planning.md:125-135` - FIXME section describing the bug -- `tests/configs/earth_mars_simple.toml` - Config with placeholder spacecraft values +- `docs/mission_planning.md:125-135` - FIXME section describing bug (now resolved) +- `src/config_loader.cpp:138-157` - Config validation implementation +- `tests/configs/earth_mars_simple.toml` - Corrected spacecraft position (LEO altitude) - `src/simulation.cpp:64-107` - `find_dominant_body()` implementation - `src/simulation.cpp:212-233` - `initialize_bodies()` implementation +- `tests/test_invalid_parent_assignment.cpp` - Test suite implementation + +## Commits +- `0239cc1` - Add test suite for invalid parent assignment bugs +- `899fa3b` - Add config validation for parent-child distances