Orbital Inclination Plane-Change Δv mechanism

Model scope

The formula and honest-label claim are correct under the fixed-speed, instantaneous, pure-plane-change assumption. Verdict is NEEDS_REVIEW because the specification does not state whether inclination_change_angle is supplied in degrees or radians, does not require a nonnegative angle, and does not define the valid angle range.

• The formula is standard for an instantaneous pure plane change when the velocity magnitude is unchanged: Δv = 2v·sin(|Δi|/2). As written, a negative Δi produces a negative Δv; the angle should be treated as a nonnegative magnitude.
• The input constraint should state 0 ≤ Δi ≤ π radians (0° to 180°) and v > 0. Values outside that range require angle normalization or a clarified interpretation.

Units and conventions

• Orbital velocity v and resulting Δv use the same speed units; the test vectors use km/s.
• The trigonometric function must interpret Δi in radians unless the implementation explicitly converts degree inputs.
• Δi is the angle between the initial and final velocity vectors at the plane-change point; for a pure inclination change at a node, this equals the plane-change angle.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "orbital_velocity_km_s": 7.8,
    "inclination_change_deg": 60
  },
  "expected_outputs": {
    "delta_v_km_s": 7.8
  },
  "working": "Convert angle: 60° × π/180 = π/3 rad. Half-angle: (π/3)/2 = π/6. sin(π/6) = 0.5. Δv = 2 × 7.8 km/s × 0.5 = 7.8 km/s."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The extreme-magnitude vector can produce JavaScript Infinity because the intermediate multiplication 2·v overflows, even though the mathematically reordered result is finite. The branch vector also exposes that an inclination change above π needs explicit rejection or normalization, which is not specified.

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