Source: https://guthlabs.ai/docs/instruments/rocket-equation-tsiolkovsky/implementation/

instrument implementation / implementation-contract

# Rocket Equation (Tsiolkovsky) implementation

A source-bound implementation contract for Rocket Equation (Tsiolkovsky); 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**: t4-233

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-final-mass input creates a division-by-zero and undefined logarithm argument; the instrument must reject it rather than return a finite value. Directional and input-representation conventions can also produce sign or interpretation errors if not explicitly labeled.

## Required corrections

````
[
  {
    "vector": 3,
    "field": "required_propellant_kg",
    "wrong": 3202.32,
    "correct": 3202.46,
    "cause": "exp(3000/3138.128) hand-evaluated slightly low"
  }
]
````

## Inspectable interface fixture

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

````
{
  "inputs": {
    "Isp_s": 300,
    "m0_kg": 10000,
    "mf_kg": 4000,
    "g0_m_per_s2": 9.80665
  },
  "expected_outputs": {
    "delta_v_m_per_s": 2695.7228
  },
  "working": "ve = Isp·g0 = 300·9.80665 = 2941.995 m/s. Mass ratio = m0/mf = 10000/4000 = 2.5. ln(2.5) = 0.916290732. Delta-v = 2941.995·0.916290732 = 2695.7228 m/s."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/rocket-equation-tsiolkovsky/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/rocket-equation-tsiolkovsky/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/rocket-equation-tsiolkovsky/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`