Source: https://guthlabs.ai/docs/instruments/circular-orbital-velocity/

instrument / verified-clean

# Circular Orbital Velocity

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/circular-orbital-velocity/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/circular-orbital-velocity/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/circular-orbital-velocity/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/circular-orbital-velocity/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**: t4-173

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The algebraic formula v = √(GM/r) is the standard circular-orbit speed formula under the two-body Newtonian model. Verdict is NEEDS_REVIEW because the exact ambiguity is whether the user supplies orbital radius or altitude, and the specification does not define the required unit conventions or radius-table convention.

### Formula and scope findings

No additional record

### Unit assumptions

- GM is the central body's standard gravitational parameter μ = GM, expressed in km^3/s^2.

- Orbital radius r is measured from the central body's center in km.

- With altitude input, r = body_radius + altitude, with both distances in km.

- The resulting velocity is in km/s.

- The calculation assumes a two-body point-mass model and a circular orbit.

## Boundary hardening

### Recorded hazards

- The specification ambiguously allows either orbital radius or altitude but does not define how altitude is converted to radius; it must use r = body_radius + altitude.

- The units for GM, radius, altitude, and output are not explicitly declared in the specification.

- The body-radii table does not specify which radius is used for non-spherical bodies, such as mean, equatorial, or reference radius.

- Reject or explicitly handle altitude values that produce r <= 0; otherwise the division and square root are invalid.

- A missing or incorrect central-body GM or radius table entry produces an incorrect result.

- The formula does not account for atmospheric drag, body rotation, oblateness, third-body perturbations, or non-circular trajectories.

- The empty honest_label is a concern: the result should be labeled as idealized two-body circular-orbit speed, not universally achievable orbital speed.

## 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": {
    "central_body": "Earth",
    "mu_km3_s2": 398600.4418,
    "body_radius_km": 6378.137,
    "altitude_km": 0,
    "orbital_radius_km": 6378.137
  },
  "expected_outputs": {
    "velocity_km_s": 7.90537
  },
  "working": "r = 6378.137 + 0 = 6378.137 km\nv = √(398600.4418 / 6378.137)\n  = √(62.4948)\n  = 7.90537 km/s"
}
````

## Related workflows

[Orbital Mission Plannerradius → v_circ](<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`