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

instrument implementation / implementation-contract

# Circular Orbital Velocity implementation

A source-bound implementation contract for Circular Orbital Velocity; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t4-173

**Effect**: Computation or source lookup only

## Input and validation requirements

- 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.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

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

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/circular-orbital-velocity/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/circular-orbital-velocity/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/circular-orbital-velocity/qualification/>)

## 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`