{
  "site": {
    "name": "Jezero Crater / Perseverance landing area",
    "latitude": 18.4446,
    "longitude": 77.4509,
    "frame": "x east / z south / y up"
  },
  "ephemeris": {
    "license": "MIT",
    "localModule": "../moon-walk/vendor/astronomy.mjs",
    "intervalUTC": "2026-10-01 / 2026-11-01",
    "commit": "865d3da7d8112bbc7911238052c6af4aaf877181",
    "source": "https://github.com/cosinekitty/astronomy",
    "orientation": "Astronomy Engine IAU WGCCRE 2009 Mars rotation axis and spin"
  },
  "satellites": [
    {
      "name": "phobos",
      "file": "phobos-ephemeris.json",
      "sampleCount": 4465,
      "source": "https://ssd.jpl.nasa.gov/api/horizons.api?format=json&COMMAND=%27401%27&CENTER=%27500%40499%27&EPHEM_TYPE=%27VECTORS%27&START_TIME=%272026-10-01%27&STOP_TIME=%272026-11-01%27&STEP_SIZE=%2710m%27&REF_PLANE=%27FRAME%27&VEC_TABLE=%272%27&CSV_FORMAT=%27YES%27&OUT_UNITS=%27KM-S%27&VEC_CORR=%27NONE%27&TIME_TYPE=%27UT%27",
      "credit": "NASA/JPL Horizons, Mars-centered ICRF geometric states, UTC",
      "timeNote": "TIME_TYPE=UT; 10-minute state vectors with cubic Hermite interpolation; not navigation ephemeris",
      "startUTC": "2026-10-01",
      "endUTC": "2026-11-01",
      "stepSeconds": 600,
      "unit": "km, km/s",
      "rawSHA256": "7e07558c2864780cfb2137cdba8a47a7075f3512303c81b5da218e8ef9e56212"
    },
    {
      "name": "deimos",
      "file": "deimos-ephemeris.json",
      "sampleCount": 4465,
      "source": "https://ssd.jpl.nasa.gov/api/horizons.api?format=json&COMMAND=%27402%27&CENTER=%27500%40499%27&EPHEM_TYPE=%27VECTORS%27&START_TIME=%272026-10-01%27&STOP_TIME=%272026-11-01%27&STEP_SIZE=%2710m%27&REF_PLANE=%27FRAME%27&VEC_TABLE=%272%27&CSV_FORMAT=%27YES%27&OUT_UNITS=%27KM-S%27&VEC_CORR=%27NONE%27&TIME_TYPE=%27UT%27",
      "credit": "NASA/JPL Horizons, Mars-centered ICRF geometric states, UTC",
      "timeNote": "TIME_TYPE=UT; 10-minute state vectors with cubic Hermite interpolation; not navigation ephemeris",
      "startUTC": "2026-10-01",
      "endUTC": "2026-11-01",
      "stepSeconds": 600,
      "unit": "km, km/s",
      "rawSHA256": "1741fde9c96d6886e4b1bc623e411ef3ea6a8a92a790b882d4dbb9e8afdc102c"
    }
  ],
  "starMap": {
    "bytes": 35997085,
    "frame": "ICRF/J2000",
    "projection": "plate carree, center RA 0h, RA increasing left",
    "source": "https://svs.gsfc.nasa.gov/4851/",
    "credit": "NASA/Goddard SVS / Ernie Wright; ESA/Gaia/DPAC, Hipparcos-2, Tycho-2",
    "sha256": "69b841cd048c2ef35543eb1c5819b322530e78aa4b0cab97ec1de3ef56a4ddcd",
    "file": "../moon-walk/starmap_2020_4k.exr",
    "delivery": {
      "manifest": "../moon-walk/starmap-2020-parts.json",
      "lossless": true,
      "parts": [
        {
          "file": "starmap_2020_4k.part-1.bin",
          "bytes": 18874368,
          "sha256": "a4914ebe3398983eb1c7ac01a9ddca182501604daeb23e6cf9c4e2b7d04d781c"
        },
        {
          "file": "starmap_2020_4k.part-2.bin",
          "bytes": 17122717,
          "sha256": "009cdf6e390ba2773a2253ff373916aa7549ec83240c3cbfb52d270493b92760"
        }
      ]
    }
  },
  "constants": {
    "source": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html",
    "gravityMeanMS2": 3.73,
    "solarDayHours": 24.6597,
    "eyeHeightM": 1.7,
    "walkSpeedMS": 1.25,
    "runSpeedMS": 3,
    "jumpInitialSpeedMS": 1.8,
    "movementNote": "Eye height and movement speeds are experience settings; gravity uses the published planetary mean, not local geodesy."
  },
  "appearance": {
    "referenceImage": "reference-materials-v1.png",
    "generatedWith": "built-in image_gen",
    "referencePhoto": "https://science.nasa.gov/photojournal/perseverances-first-full-color-look-at-mars/",
    "referencePhotoCredit": "NASA/JPL-Caltech",
    "terrain": "Observed HiRISE and coarse MOLA heights, without vertical exaggeration; source hashes and interpolation are recorded in terrain.json.",
    "materials": "AI-generated regolith and basalt tiles fixed to world coordinates; dust bump 1.4 mm, rock bump 2.8 mm are illustrative, not measured surface roughness.",
    "rocks": "Individual stones, boulders and footprints are illustrative; their exact positions and shapes are not an archaeological or rover-scene reconstruction.",
    "atmosphere": "NASA-photo-inspired ochre daytime and localized blue twilight shader; dust slider is an experience setting, not real weather or a calibrated radiative-transfer model.",
    "sunsetSource": "https://science.nasa.gov/solar-system/planets/mars/what-does-a-sunrise-sunset-look-like-on-mars/",
    "satellites": "JPL Horizons geometric positions and actual angular size using mean radii; textured ellipsoids are illustrative shape models.",
    "planets": "Directions use Mars observer heliocentric vectors with light-time correction; displayed brightness uses contextual Earth-catalog estimates, with Earth magnitude set to -2.5. It is not Mars-observer photometry.",
    "stars": "NASA HDR catalog map in J2000/ICRF; enhanced star mode is an observational display, not a naked-eye or single-exposure photograph."
  }
}