Source: https://guthlabs.ai/docs/instruments/local-gravitational-acceleration-at-altitude/mechanism/

instrument mechanism / verified-clean

# Local Gravitational Acceleration at Altitude mechanism

The inspectable method record for Local Gravitational Acceleration at Altitude, kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Model scope

The acceleration formula is correct under the disclosed spherical, non-rotating idealization. Verdict is NEEDS_REVIEW because the requested '% vs surface g' output lacks an explicit formula and the radius convention for presets is unspecified.

- g(h)=GM/(R+h)^2 is the standard spherical, non-rotating point-mass formula when M is the body's mass, R is its mean/reference radius, and h is radial altitude above that radius.

- The output '% vs surface g' has no formula specified. A standard interpretation is 100*g(h)/g(0)=100*(R/(R+h))^2, but this must be stated explicitly.

- The formula does not model planetary rotation, oblateness, local mass anomalies, or latitude-dependent surface gravity; the existing honest label correctly discloses the spherical, non-rotating idealization.

## Units and conventions

- Use G=6.67430e-11 m^3 kg^-1 s^-2.

- M must be in kilograms, R and h must be in metres, and the output g(h) is in m/s^2.

- Altitude h is radial height above the selected body's reference surface and must satisfy h>=0.

- For the test vectors, '% vs surface g' means 100*g(h)/g(0), where g(0)=GM/R^2.

- The planetary preset must define which radius is used, such as mean, equatorial, or volumetric radius; this choice affects the result.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "body": "Earth",
    "M_kg": 5.9722e+24,
    "R_m": 6371000,
    "altitude_m": 0,
    "G_m3_kg_s2": 6.6743e-11
  },
  "expected_outputs": {
    "g_m_s2": 9.820302,
    "percent_vs_surface": 100
  },
  "working": "GM=(6.67430e-11)(5.9722e24)=3.986025446e14 m^3/s^2. r=R+h=6.371000e6+0=6.371000e6 m. r^2=(6.371000e6)^2=4.0589641e13 m^2. g(h)=3.986025446e14/4.0589641e13=9.820302 m/s^2. g(0)=9.820302 m/s^2, so percent=100*(9.820302/9.820302)=100.0000%."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

The specification exposes a hard undefined-result trap at h=-R and a significant unit-convention hazard for an unlabeled altitude. A correct implementation must reject R+h=0 and require explicit altitude units; it must also reject negative altitudes if the stated above-surface domain is enforced.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/local-gravitational-acceleration-at-altitude/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/local-gravitational-acceleration-at-altitude/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/local-gravitational-acceleration-at-altitude/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`

- `BOUNDARY_HAZARD_CATALOG.json`