Source: https://guthlabs.ai/docs/instruments/orbital-inclination-plane-change-v/

instrument / verified-clean

# Orbital Inclination Plane-Change Δv

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/orbital-inclination-plane-change-v/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/orbital-inclination-plane-change-v/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/orbital-inclination-plane-change-v/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/orbital-inclination-plane-change-v/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Earth & Space (astronomy, orbital mechanics, meteorology, geology, geodesy, oceanography)

**Tranche**: tranche-4

**Evidence ID**: t4-245

**Ledger rows**: 1

No ledger note is attached.

## Review findings

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.

### Formula and scope findings

- 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.

### Unit assumptions

- 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.

## Boundary hardening

**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.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "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."
}
````

## Related workflows

[Orbital Mission Plannerv,Δi → Δv_plane](<https://guthlabs.ai/docs/instrument-workflows/orbital-mission/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`