# Kepler Zero-Revolution Lambert Endpoint Velocity Transfer

> Kepler Zero-Revolution Lambert Endpoint Velocity Transfer is a paid API for AI agents from detect.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-11-04).

Computes both initial and final velocity vectors for a two-body orbital transfer using the Lambert problem solver (zero-revolution case).

## Facts

- Endpoint: POST https://detect.halowerk.com/v1/F-TD2000-GEO-INDUSTRY-B009/kepler-zero-revolution-lambert-endpoint-velocity-transfer?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-04
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/kepler-zero-revolution-lambert-endpoint-velocity-transfer-1200445b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zlCpYKKr60NLvrQHZJqZ8

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability kepler-zero-revolution-lambert-endpoint-velocity-transfer-1200445b -d '<json body>'
```

Example prompt: Solve the Lambert problem for a zero-revolution transfer: departure position [6678, 0, 0] km, arrival position [0, 42164, 0] km, gravitational parameter 398600.4418 km³/s², transfer time 20000 seconds, and use the short-way (prograde) path — give me both the departure and arrival velocity vectors.

## When to prefer this

Use this endpoint when you need analytically correct Lambert arc boundary velocities for two-body Keplerian transfers with zero revolutions, especially in orbital mission design, delta-v budget computation, or trajectory verification workflows. Prefer this over numerical propagation when you have fixed endpoint positions and time of flight and need fast, closed-form velocity solutions.

## Known failure modes

- Transfer time too short or too long for a valid single-revolution arc may yield no solution or degenerate geometry
- Collinear or nearly-collinear position vectors can cause numerical instability or undefined transfer plane
- Exceeding the input bounds (positions outside ±10000, transfer time outside 0.001–1000000, mu outside bounds) will cause validation errors
- Ambiguous long_way flag may produce a geometrically valid but unintended transfer arc

## How this service works

Recover both boundary velocities of a bounded two-body transfer model.

## Output

Returns two 3D velocity vectors (in matching units to the input positions): the velocity at the first position (departure) and the velocity at the second position (arrival) that satisfy the specified Lambert transfer arc.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "artifact": {
   "type": "object",
   "required": [
    "lambert"
   ],
   "properties": {
    "lambert": {
     "type": "object",
     "required": [
      "data",
      "claim"
     ],
     "properties": {
      "data": {
       "type": "object",
       "required": [
        "first_position",
        "second_position",
        "gravitational_parameter",
        "transfer_time",
        "long_way"
       ],
       "properties": {
        "long_way": {
         "type": "boolean"
        },
        "transfer_time": {
         "type": "number",
         "maximum": 1000000,
         "minimum": 0.001
        },
        "first_position": {
         "type": "array",
         "items": {
          "type": "number",
          "maximum": 10000,
          "minimum": -10000
         },
         "maxItems": 3,
         "minItems": 3
        },
        "second_position": {
         "type": "array",
         "items": {
          "type": "number",
          "maximum": 10000,
          "minimum": -10000
         },
         "maxItems": 3,
         "minItems": 3
        },
        "gravitational_parameter": {
         "type": "number",
         "maximum": 1000000,
         "minimum": 0.001
        }
       },
       "additionalProperties": false
      },
      "claim": {}
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/kepler-zero-revolution-lambert-endpoint-velocity-transfer-1200445b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from detect.halowerk.com](https://www.zero.xyz/host/detect.halowerk.com/llms.txt)