# NASA Exoplanets

Confirmed exoplanets from the NASA Exoplanet Archive: planet and star lookups, habitable-zone screens, discovery stats, nearest planets and calculators.

## How to pay

Machine-payable over x402. USDC on: Base (eip155:8453), Solana (solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp), Polygon (eip155:137), Arbitrum One (eip155:42161).
No accounts. No API keys. No signup. The paying wallet is the account.

## Machine-readable

- OpenAPI: https://exoplanets-nasa.x402tookit.com/openapi.json
- x402 manifest: https://exoplanets-nasa.x402tookit.com/.well-known/x402
- Catalog (free): https://exoplanets-nasa.x402tookit.com/catalog
- Health (free): https://exoplanets-nasa.x402tookit.com/health
- Uptime (free): https://exoplanets-nasa.x402tookit.com/uptime

## Endpoints (10)

### GET /discovery-stats — $0.03
Confirmed exoplanet discovery counts by year and by detection method, with totals, the peak year and a cumulative series.
Params: fromYear?: integer, toYear?: integer, method?: string
Example: https://exoplanets-nasa.x402tookit.com/discovery-stats?fromYear=2010&toYear=2025&method=Transit

### GET /earth-comparison — $0.02
Planet size, mass, density, gravity and escape speed as ratios to Earth, with insolation if luminosity and orbit are given.
Params: radiusEarth: number, massEarth?: number, luminositySolar?: number, orbitAu?: number
Example: https://exoplanets-nasa.x402tookit.com/earth-comparison?radiusEarth=0.92&massEarth=0.692

### GET /equilibrium-temperature — $0.02
Planet equilibrium temperature in K, C and F from star luminosity or temperature and radius, orbit distance and albedo.
Params: orbitAu: number, luminositySolar?: number, teffK?: number, radiusSolar?: number, albedo?: number
Example: https://exoplanets-nasa.x402tookit.com/equilibrium-temperature?orbitAu=1&luminositySolar=1&albedo=0.3

### GET /habitable-zone — $0.02
Habitable-zone edges in AU for a star from luminosity or radius, plus temperature (Kopparapu 2013), and where an orbit falls.
Params: teffK: number, luminositySolar?: number, radiusSolar?: number, orbitAu?: number, periodDays?: number, massSolar?: number
Example: https://exoplanets-nasa.x402tookit.com/habitable-zone?teffK=5780&luminositySolar=1&orbitAu=1

### GET /hill-radius — $0.02
Hill radius of a planet in AU and km from its mass, orbit, eccentricity and star mass, with the stable-moon region.
Params: planetMass: number, massUnit?: string, orbitAu: number, eccentricity?: number, starMassSolar?: number
Example: https://exoplanets-nasa.x402tookit.com/hill-radius?planetMass=1&massUnit=earth&orbitAu=1&eccentricity=0.0167&starMassSolar=1

### GET /host-star-planets — $0.02
All confirmed planets of a host star by name, with star properties and each planet's period, size and habitable-zone position.
Params: star: string
Example: https://exoplanets-nasa.x402tookit.com/host-star-planets?star=TRAPPIST-1

### GET /nearest-planets — $0.02
Closest known exoplanets to the Sun in light-years, optional size filter, with star type, orbit and habitable-zone position.
Params: limit?: integer, maxDistancePc?: number, minRadiusEarth?: number, maxRadiusEarth?: number
Example: https://exoplanets-nasa.x402tookit.com/nearest-planets?limit=10&maxDistancePc=8&maxRadiusEarth=1.6

### GET /planet-habitability — $0.02
Habitable-zone screen for a named exoplanet: orbit versus the zone edges, size class and rocky-planet plausibility.
Params: name: string
Example: https://exoplanets-nasa.x402tookit.com/planet-habitability?name=Kepler-442+b

### GET /planet — $0.02
Confirmed exoplanet by name: star, orbit, size, mass, temperature, discovery, Earth ratios and habitable-zone position.
Params: name: string
Example: https://exoplanets-nasa.x402tookit.com/planet?name=TRAPPIST-1+e

### GET /transit-depth — $0.02
Transit depth (Rp/Rs squared) in percent and ppm from planet and star radius, plus duration if period and star mass are given.
Params: planetRadius: number, planetUnit?: string, starRadiusSolar: number, periodDays?: number, starMassSolar?: number, impactParameter?: number
Example: https://exoplanets-nasa.x402tookit.com/transit-depth?planetRadius=1&planetUnit=earth&starRadiusSolar=1&periodDays=365.25&starMassSolar=1

## Terms

Exoplanet data comes from the NASA Exoplanet Archive (Caltech/IPAC) public TAP service and local computation, provided as is. Planet parameters are measurements with uncertainties and many are model-derived; habitable-zone results are a screening of orbit versus a published climate model, not a statement that a planet is habitable or has life. Not advice for any decision. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program.