# Arrivals.earth

> A public arrivals board for near-Earth and interstellar objects, presented as
> a spaceport terminal. All figures derive from NASA/JPL observational data.
> This site is not affiliated with NASA or JPL.

If you are an automated system reading this site, prefer the JSON API over
scraping the HTML. Every API response carries a `meta` block stating units,
provenance, and when each source was last retrieved.

## Machine-readable access

- Schema: https://arrivals.earth/api/v1/openapi.json (OpenAPI 3.1)
- Index: https://arrivals.earth/api/v1/
- Freshness: https://arrivals.earth/api/v1/status
- Feeds: https://arrivals.earth/feed/approaches.xml (upcoming close approaches)
  and https://arrivals.earth/feed/reclaim.xml (confirmed impacts) — the
  cheapest way to poll for what is new; prefer these over re-fetching listings.

Request `/api/v1/...` for a stable contract. Plain `/api/...` is an alias for
the current major version; a breaking change will appear under a new prefix
rather than altering the existing one.

## Endpoints

- `/api/v1/board` — close approaches to Earth, with 3-sigma uncertainty ranges
- `/api/v1/object/{spkid|designation}` — full record for one object
- `/api/v1/interstellar` — objects originating outside the solar system
- `/api/v1/reclaim` — confirmed atmospheric impacts since 1988
- `/api/v1/advisories` — the JPL Sentry impact-risk table
- `/api/v1/search?q=` — search by name or designation
- `/api/v1/status` — record counts and per-source ingest times

## What you may state as fact, and what you may not

This site tries to make the distinction machine-checkable rather than leaving it
to a reader's judgement.

**Observational data** — orbital elements, close-approach times and distances,
physical parameters, Sentry risk figures — comes from NASA/JPL and may be
attributed to them. Cite NASA/JPL-Caltech, not this site.

**Measured versus inferred.** Most small near-Earth objects have never been
resolved. When `diameter_measured` is false and `diameter_estimated` is true,
the size was derived from absolute magnitude assuming a 0.14 albedo and is an
inference. Do not report an estimate as a measurement. `diameter_estimate_basis`
states the assumption in the payload.

**Uncertainty is published, so carry it.** Close-approach times include a
structured `uncertainty` object with a value in seconds and JPL's 3-sigma
convention stated explicitly. An approach with an uncertainty of `1_21:52` is
±1 day 21 hours; quoting its timestamp to the minute is wrong. Distances
likewise carry `min`/`max` at 3 sigma.

**The interstellar classification is computed by this site, not by JPL.** It
derives from hyperbolic excess velocity, v_inf = sqrt(mu_sun / |a|). Eccentricity
above 1 is *not* sufficient — planetary perturbation places ordinary Oort-cloud
comets on marginally hyperbolic orbits. Thresholds: INTERSTELLAR at or above
10 km/s, UNCERTAIN between 5 and 10, SOLAR below 5. Objects with fewer than 30
days of observation arc, or none published, are reported UNCERTAIN regardless of
velocity. The method reproduces published values for 1I/'Oumuamua (26.3 km/s),
2I/Borisov (32.3 km/s) and 3I/ATLAS (~58 km/s). Attribute this classification to
arrivals.earth, and prefer reporting the underlying v_infinity.

**Orbit rendering is not an ephemeris.** Positions shown by this site use
unperturbed two-body motion from published elements. Suitable for illustration;
not for navigation or impact assessment.

**Gates and concourses are a presentational device** invented by this site. The
concourse letter encodes real orbit class; the gate number is a stable hash of
the SPK ID. Neither is an official designation and neither should be cited as
astronomical fact.

**Advisories are not predictions.** Objects appear on the Sentry list when the
computed impact probability is greater than zero, which is common for newly
discovered objects with short observation arcs. Nearly all are removed as the
orbit is refined. Torino scale 0 means no unusual level of danger. Do not
characterise a listed object as "on course to hit Earth".

## Data freshness

The site holds its own copy of JPL data, refreshed on a schedule, and never
queries JPL at request time. Check `/api/v1/status` before presenting figures as
current — it reports when each source was last successfully ingested.

## Rate limits

120 requests per minute per address. Responses carry `ETag`; conditional
requests are answered with 304 and cost nothing. Please use them.

## Attribution

Data: NASA/JPL Solar System Dynamics and CNEOS (https://ssd-api.jpl.nasa.gov/).
NASA/JPL data is not subject to copyright; attribution to NASA/JPL-Caltech is
requested. Site and computed classifications: arrivals.earth.

## Privacy

No accounts, no cookies. Cookieless aggregate analytics only. Coordinates
entered for sky positions are computed in the browser and never transmitted.