Task 194: EP02 Counterfactual IF Analyses

Status: DONE

Goal

Add counterfactual "IF" analyses (反事実分析) to EP02. Currently EP02 has only 1 IF analysis (ep02-exploration-04: alternative Saturn moon capture). All other episodes now have 2 IF analyses each. EP02 should match.

Background

IF analysis coverage:

• EP01: 2 IFs (perijove vs high-altitude capture, 150h normal route)
• EP02: 1 IF (alternative moon capture) ← gap
• EP03: 2 IFs (wrong nav choice, alternative Uranus moon targets)
• EP04: 2 IFs (plasmoid evasion cascade, Titania stay analysis)
• EP05: 2 IFs (no Jupiter flyby direct route, nozzle-preserving safe route)

EP02 IF Scenarios to Add

1. What if partial thrust instead of trim-only during 455-day transit?

- The report already notes 1% thrust could cut transit to ~33 days

- Explore: trim-only (455d actual), 10% thrust, 25% thrust, 50% thrust

- Key question: Did きりたん have to endure 455 days, or could partial thrust (within damage constraints) have shortened the trip?

- Cross-reference: frame stress 114%, cold sleep is explicitly depicted

- Narrative implication: The 455-day ballistic choice was the safe choice for the damaged ship

1. What if Jupiter escape velocity had been lower/higher?

- The 0.53 km/s solar escape velocity margin is flagged as critical

- Explore: what minimum v∞ is needed to reach Saturn without correction burns?

- What if escape velocity had been 0.5 km/s less? Would Saturn be unreachable?

- Connects to the "no correction maneuver possible" constraint

Approach

• Add ep02-exploration-05 and ep02-exploration-06 to ep02.md
• Follow the same MDX exploration format as existing IF analyses in other episodes
• Include scenario tables with quantitative results
• Reference existing calculations where possible (the 33-day figure is already computed)

Dependencies

• EP02 report (ep02.md) — DONE
• EP02 calculations (ep01-05_calculations.json) — available
• Pattern: follow EP01/EP03/EP04 IF analysis format