# Hohmann Transfer Rendezvous — Debug Report

## Root Cause

The test uses **two different time variables** that are off by a factor of 10:

- `sim->time` — simulation's internal clock, increments by `sim->dt = 0.1` each `update_simulation()` call
- `sim_time` — test loop counter, increments by `DT = 1.0` each iteration

The dump milestones use `sim_time`:
```cpp
if (i == int(wait_time / DT))  // wait_time=60062.65, DT=1.0 → i=60062
```

But the maneuvers trigger on `sim->time`. At `i=60062`, `sim->time = 6006.2` — **10x too early**. The departure maneuver actually fires at `i ≈ 600627` (when `sim->time ≥ 60062.65`).

## What This Means

The "AFTER DEPARTURE BURN" dump at `i=60064` shows `exec=0` — the burn hasn't happened yet. The dumps are capturing state at completely wrong simulation times.

## Why the 11,579 km Separation

With `TIME_STEP = 0.1`, the Hohmann transfer parameters (`wait_time = 60062.65`, `arrival_time = 62804.47`) were computed assuming an **instantaneous burn at exactly `wait_time`**.

The sub-step interpolation now propagates `burn_dt = 0.05` (from `sim->time = 60062.6` to `trigger = 60062.65`), then burns, then propagates `remaining = 0.05`. This puts the chaser at a **different orbital position at burn time** than the old code, which propagated the full `0.1` step before burning.

The chaser's true anomaly at `t = 60062.65` differs from its true anomaly at `t = 60062.7` by ~0.006 rad. The Hohmann phasing was calculated for one starting position but the burn now happens at the other.

## The Two Options

1. **Update test expectations** — The sub-step interpolation is *more physically accurate*. The test expectations were tuned to the old quantized (step-boundary) behavior. The 11,579 km error is the old test asserting old behavior.

2. **Change trigger logic** — If you want the burn to fire at the step boundary (old behavior), revert `scheduled_dt` to `sim->dt` for time triggers. But then you lose sub-step accuracy.

## Files to Look At in New Session

- `tests/test_rendezvous.cpp` line ~571 — the rendezvous assertion (expects <100m separation)
- `src/maneuver.cpp` `check_maneuver_trigger()` — the TRIGGER_TIME sub-step logic
- `tests/test_rendezvous.toml` — initial conditions for the rendezvous scenario