Task 065: Communications Systems Analysis

Status: DONE

Motivation

Human directive: 通信の描写が多いのでそれについても考察したい

SOLAR LINE has extensive communication scenes. Analyzing the physics of these adds depth to the 考察.

Completed Work (2026-02-24)

Rust comms module (crates/solar-line-core/src/comms.rs)

• light_time_seconds/minutes(): One-way light delay for any distance
• round_trip_light_time(): Two-way delay
• planet_light_delay(): Light delay between any two planets at a Julian Date
• ship_planet_light_delay(): Ship-to-planet light delay
• distance_between_positions(): Distance from heliocentric positions
• planet_distance_range(): Min/max distance between planet pairs
• planet_light_delay_range(): Min/max light delay
• free_space_path_loss_db(): FSPL for link budget analysis
• CommFeasibility: Classification (RealTime/NearRealTime/Delayed/DeepSpace)
• comm_timeline_linear(): Communication timeline along a route
• 21 TDD tests (including episode-specific tests)

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

• speed_of_light, light_time_seconds/minutes, round_trip_light_time
• planet_light_delay, ship_planet_light_delay
• planet_distance_range, planet_light_delay_range
• free_space_path_loss_db, comm_feasibility_label
• comm_timeline_linear (flat array output)
• 5 new WASM tests

Communications analysis report (reports/data/summary/communications.json)

• Complete per-episode analysis of all communication scenes (EP01-EP05)
• Light delay calculations for every route segment
• Dialogue citations with timestamps
• Analysis of 可視光通信 (FSOC) technical feasibility
• Communication delay profile across entire route
• Relay base network implications
• 7 verified items (all pass physical consistency check)
• Japanese language report, published to GitHub Pages

Test counts

• 143 Rust core tests (+21 comms) + 34 WASM tests (+5 comms) = 177 Rust total
• 946 TS tests (unchanged)
• Total: 1,123 tests (0 failures)

Key findings

1. All communication scenes in SOLAR LINE respect light-speed delay — no real-time Earth dialogue during deep space
2. Mars control and Ganymede control communications are near-field (< 0.1s delay) ✅
3. 455-day ballistic transit in EP02 has no Earth communication — physically correct
4. EP05 可視光通信 matches real FSOC technology (NASA DSOC demonstrated 2023)
5. Relay bases provide store-and-forward capability (solar system DSN analog)
6. Inertial navigation drift and calibration signal in EP05 is technically accurate