Vis-Viva / Elliptical Orbit Energy Calculator implementation

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

t4-047

Effect

Computation or source lookup only

Input and validation requirements

The advertised apoapsis and periapsis speeds cannot be computed from the stated inputs GM, current radius r, and semi-major axis a alone; eccentricity or both apsis radii are required. The calculator also needs explicit rejection handling for r=0 and for negative square-root radicands, especially at and beyond r=2a.

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": {
    "GM": 398600.4418,
    "r": 7000,
    "a": 7000,
    "units": "km, km³/s²"
  },
  "expected_outputs": {
    "speed": 7.54605329,
    "specific_energy": -28.47146013,
    "apoapsis_speed": null,
    "periapsis_speed": null
  },
  "working": "v²=398600.4418×(2/7000−1/7000)=398600.4418×(1/7000)=56.9429202571 km²/s²; v=√56.9429202571=7.54605329 km/s. ε=−398600.4418/(2×7000)=−398600.4418/14000=−28.47146013 km²/s². Apoapsis and periapsis speeds are not determined because eccentricity or apoapsis/periapsis radius was not supplied."
}

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