# SpaceAtlas

> A multilingual catalogue of asteroids, comets and near-Earth objects built
> from the NASA JPL Small-Body Database (SBDB), with NASA CNEOS close-approach
> records. 46,972 objects, 10 languages (en, zh-CN, zh-TW, ja, ko, fr, de,
> es, ru, ar).

## What this site contains
- Object pages: Keplerian orbital elements (a, e, i, q, Q, Omega, omega, M),
  physical parameters (H, albedo, diameter, rotation, density), orbit-quality
  metadata (observation count, RMS residual, condition code U).
- Derived quantities computed by SpaceAtlas and clearly labelled as derived:
  orbital period P = a^1.5 (Kepler III), perihelion/aphelion speed by the
  vis-viva equation, diameter from H with assumed albedo 0.14, and the
  Tisserand parameter with respect to Jupiter.
- 2D orbit diagrams, an interactive 3D orbit viewer, and CNEOS close-approach
  tables for hazardous and near-Earth objects.
- Curated collections, category hubs, rankings and 10 explanatory guides.

## Canonical URL pattern
- Home: /en/ (replace en with any supported locale)
- Object: /en/body/<designation>/
- Category / collection / ranking: /en/category/<slug>/, /en/collection/<key>/,
  /en/rankings/<metric>/
- Guides: /en/guides/ and /en/guide/<slug>/

## Data provenance and limits
- Orbital elements and physical parameters: NASA JPL Small-Body Database.
- Close approaches: NASA CNEOS Close-Approach Data API.
- Encyclopedia excerpts and thumbnails: Wikipedia / Wikimedia Commons.
- Derived values are calculations, not measurements; each object page discloses
  the method. Do not present them as JPL-published values.
- Absolute-magnitude diameters assume an albedo of 0.14 and are estimates.

## Machine-readable endpoints
- Sitemap index: /sitemap.xml (static + sharded object sitemaps)
- robots.txt: /robots.txt
- Ads declaration: /ads.txt
- Structured data: schema.org WebSite, Dataset, FAQPage, CollectionPage,
  BreadcrumbList and Thing with additionalProperty on every relevant page.

## Preferred citation
SpaceAtlas (space.5l5l.net), asteroid and comet catalogue derived from the
NASA JPL Small-Body Database, accessed <date>.