{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Sovereign Apollo Telemetry Frame",
  "description": "Normalized downlink frame derived from Luminary099 DOWNLINK_LISTS + DOWN_TELEMETRY_PROGRAM (DOCUMENTED) + modern hash wrapper (MODERN DESIGN)",
  "type": "object",
  "required": ["met", "met_seconds", "list_id", "words", "hash_chain"],
  "properties": {
    "met": { "type": "string", "pattern": "^\\d{3}:\\d{2}:\\d{2}$", "description": "Mission Elapsed Time" },
    "met_seconds": { "type": "integer", "description": "MET seconds from liftoff" },
    "list_id": { "type": "integer", "minimum": 0, "maximum": 5, "description": "Downlink list index (0=orbital, 1=powered, 2=landing)" },
    "list_name": { "type": "string", "enum": ["ORBITAL", "POWERED", "LANDING", "COST_PLUS_1", "COST_PLUS_2"] },
    "vehicle_state": { "type": "string", "description": "From State vector: RN/VN" },
    "guidance_mode": { "type": "string" },
    "words": {
      "type": "array",
      "minItems": 1,
      "maxItems": 100,
      "items": {
        "type": "object",
        "required": ["addr_oct", "symbol", "value_oct", "value_dec"],
        "properties": {
          "addr_oct": { "type": "string", "pattern": "^[0-7]{4}$" },
          "symbol": { "type": "string", "description": "Erasable symbol e.g., RN1, VN2, PIPTIME" },
          "value_oct": { "type": "string" },
          "value_dec": { "type": "integer" }
        }
      }
    },
    "sync_word": { "type": "string", "description": "Frame sync Barker (original 0x7776) hex" },
    "hash_chain": {
      "type": "object",
      "description": "MODERN DESIGN: hash chain for integrity",
      "required": ["prev_hash", "frame_hash"],
      "properties": {
        "prev_hash": { "type": "string", "pattern": "^[a-f0-9]{64}$" },
        "frame_hash": { "type": "string", "pattern": "^[a-f0-9]{64}$" },
        "algorithm": { "type": "string", "const": "SHA-256" }
      }
    }
  },
  "example": {
    "met": "102:45:03",
    "met_seconds": 369903,
    "list_id": 2,
    "list_name": "LANDING",
    "vehicle_state": "surface",
    "guidance_mode": "P68",
    "words": [
      { "addr_oct": "01410", "symbol": "RN1", "value_oct": "00000", "value_dec": 0 },
      { "addr_oct": "03400", "symbol": "DNECADR", "value_oct": "03412", "value_dec": 1802 }
    ],
    "sync_word": "0x7776",
    "hash_chain": { "prev_hash": "abc...def", "frame_hash": "123...789", "algorithm": "SHA-256" }
  }
}