Ground Track / Orbital Period vs Altitude mechanism

Model scope

NEEDS_REVIEW because the exact ambiguity is: the specification claims a rough ground-track repeat but supplies no ground-track-repeat formula, required orbital inputs, or defined repeat output. The period and orbits-per-day formulas are standard only under the stated circular-orbit and unit assumptions.

• The implied circular-orbit formula should be stated explicitly as T = 2π√(a³/μ), with a = Rₑ + h; 'T from Kepler' is underspecified.
• Altitude and orbital period do not determine a ground-track repeat. A repeat calculation also requires at least orbital inclination, Earth's rotation rate, and a specified resonance/repeat criterion; with perturbations, nodal regression and other orbital elements are additionally relevant.
• The stated outputs list period and orbits per day, but the instrument description also claims a rough ground-track repeat without providing a formula or output definition.
• The formula assumes a circular orbit. An altitude alone is insufficient for an eccentric orbit, whose period depends on semimajor axis rather than instantaneous altitude.

Units and conventions

• Use Earth gravitational parameter μ = 398600.4418 km³/s².
• Use mean/equatorial Earth radius Rₑ = 6378.137 km; altitude must be measured from the same reference radius.
• Use altitude in kilometers in the orbital formula, or explicitly convert meters to kilometers first.
• Compute period T in seconds and orbits per day as 86400/T.
• For the period-input mode, the supplied period is assumed to be in seconds and positive.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "altitude_km": 0,
    "mu_km3_s2": 398600.4418,
    "earth_radius_km": 6378.137
  },
  "expected_outputs": {
    "period_s": 5069.34,
    "orbits_per_day": 17.0436
  },
  "working": "a = Rₑ + h = 6378.137 + 0 = 6378.137 km. T = 2π√(a³/μ) = 2π√(6378.137³ / 398600.4418) ≈ 5069.34 s. Orbits/day = 86400 / 5069.34 ≈ 17.0436."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

A zero supplied period makes the orbits-per-day calculation undefined, and an unspecified altitude unit permits materially different outputs for the same numeric input.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json