The depot's distant retrograde orbit is classified marginal — the lunar-economy regime: not chaotic (it does not eject) and not perfectly stable (nothing near the Moon is), but nearly self-holding. Its local divergence rate sets the station-keeping clock: a correction about every 150 days. For contrast, an L₂ gateway saddle diverges roughly five times faster — a correction every month. SELENOGRAPH returns this distinction before an orbit is committed.
| Quantity | Value |
|---|---|
| Depot DRO — divergence rate | 0.029 |
| Depot — correction interval | ~148 d |
| L₂ gateway saddle — divergence rate | 0.141 |
| Gateway — correction interval | ~31 d |
| Relative station-keeping cost (gateway / depot) | ~5× |
Cislunar transfers do not run in straight lines — they ride low-energy corridors that thread the L₁ and L₂ gateways (the cheap passes on the fuel landscape). A corridor is open only when the spacecraft's energy crosses a precise threshold; below it, the gate is shut and the regions are dynamically separated. For this depot, the inbound (L₁) and outbound (L₂) corridors open below Jacobi energy C = 3.172 — so fuel is committed to the lowest-cost route, in the window when it is open.
Cislunar space has a hard carrying capacity — a ceiling on how many independent orbits can coexist before collisions become structurally unavoidable. Below the ceiling almost any arrangement is clear; at the ceiling, the collision-free fraction does not fade — it falls to exactly zero. Because that ceiling is exact and combinatorial, not a probabilistic Monte-Carlo estimate, it is a usable input for traffic and capacity planning. This is the question Space Domain Awareness asks for Earth orbit, answered for cislunar space before the region fills.
| Spacecraft (orbital families) placed | Collision-free arrangements |
|---|---|
| 1–2 | ~100% |
| 3 | 47% |
| 4 | 17% |
| 5 | 2% |
| 6 or more | 0% — structurally unavoidable |
Structural fractions for the canonical configuration; the calibrated absolute count for a specific region and keep-out radius is a per-mission deliverable.
A relay constellation must hold formation without its members drifting into one another. Two craft on slightly different orbits drift — but the drift is a predictable beat, the slow oscillation of their closest approach, not a runaway. Because the beat is predictable, the intervals of closest approach — the contact and maneuver windows — recur on a fixed schedule. You plan handoffs and phasing burns for the green, instead of fighting the drift.
determinism: the same (mission, configuration) input reproduces this analysis. The relative geometry is characterized exactly in advance — commensurate pairs close into bound relative orbits; incommensurate pairs beat on the schedule above.