Task 64: Attitude Control Precision & Stability Analysis

Task 064: Attitude Control Precision & Stability Analysis

Status: DONE

Motivation

Human directive: 要求される姿勢制御精度や姿勢安定度についても考察したい

SOLAR LINE features high-acceleration brachistochrone maneuvers (20-30 m/s²) and precision navigation. The attitude control requirements hadn't been analyzed yet.

Completed

Rust Core (`crates/solar-line-core/src/attitude.rs`)

8 attitude control functions with 10 unit tests:

miss_distance_km: Pointing error → lateral displacement during burn
required_pointing_rad: Inverse — desired miss → required accuracy
flip_angular_rate: 180° flip maneuver angular velocity
flip_angular_momentum: Ship I × ω
flip_rcs_torque: Trapezoidal profile RCS torque for flip
velocity_error_from_pointing: Pointing offset → velocity error
accuracy_to_pointing_error_rad: Navigation accuracy fraction → angle
gravity_gradient_torque: Gravity gradient on elongated spacecraft

WASM Bindings (`crates/solar-line-wasm/src/lib.rs`)

All 8 functions exposed with flat f64 API.

Analysis Report (`reports/data/summary/attitude-control.json`)

Dedicated summary page with 7 sections:

Overview — inertia models, analysis scope
EP01 — pointing sensitivity table (0.001″→1°), flip maneuver dynamics (60s→600s)
EP03 — 1.23° nav crisis matches tan calculation to 0.2%, INS drift rate consistent with modern RLG
EP04 — thrust misalignment torque analysis, 65% output RCS requirements
EP05 — 20km@18.2AU = 1.5 milliarcsec (33× Hubble), nozzle asymmetry → seconds to diverge
LEO gravity gradient — 88 N·m max, manageable
Conclusion — all findings summarized, SOLAR LINE respects attitude physics implicitly

DAG

Added analysis.attitude_control and report.attitude_control nodes
DAG: 60 nodes, 300 edges (was 58/267)

Key Findings

EP01: Ganymede SOI requires ≤37.6″ pointing — achievable with star trackers
EP03: 1.23° nav error = 14,390,000 km miss (show says 14,360,000 km — 0.2% match!)
EP03: INS drift rate 0.01°/h × 143h ≈ 1.43° — matches the 1.23° discrepancy
EP05: 20km arrival precision = 1.5 milliarcsec angular accuracy (impressive but achievable with MCC)
EP05: 0.1% nozzle asymmetry → 1° misalignment in 3.4s (needs constant RCS correction)

Test Results

Rust: 153 core + 34 WASM = 187 tests passing
TypeScript: 998 tests passing
Total: 1,185 tests (0 failures)