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

instrument implementation / implementation-contract

# Circular Orbital Velocity & Period Calculator implementation

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

Status: **VERIFIED_WITH_ERRATA**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-with-binding-errata

**Evidence ID**: t4-023

**Effect**: Computation or source lookup only

## Input and validation requirements

The calculator has undefined behavior at zero or negative orbital radius and can produce materially different results if negative altitude is interpreted as signed depth versus an absolute altitude magnitude. The radius-input and altitude-input branches agree for valid positive values.

## Required corrections

````
[
  {
    "vector": 4,
    "field": "v/T/min",
    "wrong": "v 3362.27, T 7081.57, min 118.03",
    "correct": "v 3361.87, T 7082.40, min 118.04",
    "cause": "GM correct; GM/r division slipped (1.130483e7 vs true 1.130218e7)"
  }
]
````

## Inspectable interface fixture

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

````
{
  "inputs": {
    "central_body": "Earth",
    "mass_kg": 5.972e+24,
    "G_m3_kg_s2": 6.6743e-11,
    "body_radius_m": 6371000,
    "altitude_m": 400000,
    "orbital_radius_m": 6771000
  },
  "expected_outputs": {
    "orbital_velocity_m_s": 7672.49,
    "period_s": 5544.93,
    "period_min": 92.42
  },
  "working": "GM=(6.67430×10⁻¹¹)(5.972×10²⁴)=3.98589196×10¹⁴ m³/s². r=6,371,000+400,000=6,771,000 m. v=√(GM/r)=√[(3.98589196×10¹⁴)/(6.771×10⁶)]=√(5.886711×10⁷)=7,672.49 m/s. T=2π√(r³/GM)=2π(r/v)=2π(6,771,000/7,672.49)=2π(882.50)=5,544.93 s=5,544.93/60=92.42 min."
}
````

## Other records

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

- `tranche errata record`