{
  "schema": "spacetrc-orbit-provenance-v1",
  "retrievedAt": "2026-10-24",
  "sources": [
    {
      "id": "celestrak-stations",
      "files": [
        "stations-raw.json",
        "satellites.json"
      ],
      "sourceUrl": "https://celestrak.org/NORAD/elements/gp.php?GROUP=stations&FORMAT=JSON",
      "access": "Public CelesTrak GP download; resource policy requires avoiding repeated requests inside the two-hour update interval. No automatic external query is made by the interface.",
      "documentation": "https://celestrak.org/NORAD/documentation/gp-data-formats.php",
      "policy": "https://celestrak.org/usage-policy.php",
      "processing": "The original stations JSON response is retained. The ISS record with NORAD 25544 is selected without changing orbital values."
    },
    {
      "id": "celestrak-turksat6a",
      "files": [
        "turksat6a-raw.json",
        "satellites.json"
      ],
      "sourceUrl": "https://celestrak.org/NORAD/elements/gp.php?CATNR=60233&FORMAT=JSON",
      "processing": "The original single-record GP JSON response is retained. TÜRKSAT 6A NORAD 60233 is selected without changing orbital values."
    },
    {
      "id": "nasa-mms1",
      "files": [
        "mms1-source.json",
        "mms1-trajectory.json"
      ],
      "sourceUrl": "https://sscweb.gsfc.nasa.gov/WS/sscr/2/locations/mms1/20161016T000000Z,20161019T000000Z/geij2000/?resolutionFactor=10",
      "documentation": "https://sscweb.gsfc.nasa.gov/WebServices/REST/",
      "access": "NASA SSCWeb public REST service. The service documentation explicitly permits cross-origin web usage; this application serves an archived response and does not contact SSCWeb automatically.",
      "provenance": "https://sscweb.gsfc.nasa.gov/sscweb_data_provenance.html",
      "upstream": "MMS1_MEC_SRVY_L2_EPHT89D, mms1_mec_r_eci, definitive MMS1 ephemeris supplied via NASA SPDF SSCWeb.",
      "processing": "Unwrapped typed JSON containers; selected UTC Time and X/Y/Z of GEI_J_2000 coordinates, rounded coordinates to six decimals in km. 432 samples from 2016-10-16T00:00:30Z to 2016-10-18T23:50:30Z at 600-second cadence. Source response retained.",
      "credit": "NASA SPDF SSCWeb and the MMS mission science/operations teams. No endorsement implied."
    },
    {
      "id": "satellite-js",
      "files": [
        "satellite.min.js",
        "SATELLITE-LICENSE.txt"
      ],
      "version": "6.0.1",
      "sourceUrl": "https://cdn.jsdelivr.net/npm/satellite.js@6.0.1/dist/satellite.min.js",
      "upstream": "https://github.com/shashwatak/satellite-js",
      "license": "MIT; see SATELLITE-LICENSE.txt",
      "processing": "Vendored unmodified minified UMD build. SGP4/SDP4 with WGS72 propagation constants; observer transforms use the library WGS84 geodetic ellipsoid."
    },
    {
      "id": "sgp4-reference",
      "sourceUrl": "https://celestrak.org/publications/aiaa/2006-6753/AIAA-2006-6753-Rev3.pdf",
      "title": "Vallado et al. Revisiting Spacetrack Report #3, AIAA 2006-6753, Rev 3.",
      "processing": "Verification tests compare Vanguard 1 catalog 5 TEME state vectors at 0 and 360 minutes against Appendix E. No paper bytes redistributed."
    }
  ],
  "sha256": {
    "mms1-trajectory.json": "0d9cd8b850a00d8181d1c7ed5ac786ddbc336ee7660d4c16a134427ab6a1abcf",
    "SATELLITE-LICENSE.txt": "1432ff8b94b91db9f242d908e09f2ecb1a0804a03f76ba844cf052c7bb614d9e",
    "stations-raw.json": "975e815e6b24bd2dc95166ed197596ddc2c395eefe9c003418fe0e236db2c2b4",
    "satellite.min.js": "6fd7487abb99bec37ea2c8d1f5739b59143a6130a00b0faa6c44dd44585aebbf",
    "satellites.json": "53e2bbbcd158883355429e260369fff1c8ddcbfe3d1d5e88f54f6935de8b9ab9",
    "mms1-source.json": "206ca4be92dbb2bf35c95a63451c6891743a733591ff57e795b35f41aa91822c",
    "turksat6a-raw.json": "9204c0a95bab6e6ed027411a92fad67ac59e0fd5b41d95d2df0c32596d36ccf3"
  },
  "limitations": [
    "The CelesTrak snapshots have epochs on 2026-10-24; packaged data ages and must not be described as live telemetry. Propagation is restricted to plus or minus 72 hours from each epoch.",
    "Approximate TEME-to-Earth-fixed rotation uses Greenwich mean sidereal time without full IERS Earth orientation/polar motion. Observer geometry is educational and geometric, not optical naked-eye visibility.",
    "MMS1 is a selected historical archive. Piecewise linear interpolation between 600-second samples is a visual replay; derived speeds are segment averages. There is no extrapolation.",
    "JPL SSD API is not called, proxied, or embedded. No account, secret, paid API, geolocation or automatic external dataset request is used."
  ],
  "reuse": "Scientific source attribution and policy references are provided individually. No blanket Creative Commons license is asserted for third-party data."
}