{
  "id": "ufo",
  "name": "UHF Follow-On (UFO)",
  "aliases": [],
  "domain": "space",
  "country": "USA",
  "category": "Narrowband military communications constellation",
  "status": "in-service",
  "fielded": 1993,
  "operators": [
    "USA"
  ],
  "summary": "Legacy UHF satellites that replaced FLTSATCOM and Leasat; being superseded by MUOS.",
  "specs": [
    {
      "k": "orbit_regime",
      "v": "GEO",
      "src": [
        "asf-ultra-high-frequency-follow-on"
      ],
      "conf": "high"
    },
    {
      "k": "sats_count",
      "v": 4,
      "src": [
        "asf-ultra-high-frequency-follow-on"
      ],
      "conf": "medium",
      "note": "UFO 8, 9, 10 (Block 3) and UFO 11 (Block 4) remain active of 11 launched"
    },
    {
      "k": "first_launch",
      "v": 1993,
      "src": [
        "asf-ultra-high-frequency-follow-on"
      ],
      "conf": "medium"
    },
    {
      "k": "mass_kg",
      "v": 3206,
      "src": [
        "asf-ultra-high-frequency-follow-on"
      ],
      "conf": "medium",
      "note": "7,068 lb (Block 3)"
    },
    {
      "k": "power_w",
      "v": 3800,
      "src": [
        "asf-ultra-high-frequency-follow-on"
      ],
      "conf": "medium",
      "note": "Block 3"
    },
    {
      "k": "contractor",
      "v": "Hughes (Blocks 1–3), Boeing (Block 4)",
      "src": [
        "asf-ultra-high-frequency-follow-on"
      ],
      "conf": "medium"
    },
    {
      "k": "on_orbit",
      "v": 11,
      "src": [
        "celestrak-gp"
      ],
      "conf": "high",
      "note": "Payloads with current element sets in the public catalog, active or not."
    },
    {
      "k": "active_sats",
      "v": 4,
      "src": [
        "celestrak-gp"
      ],
      "conf": "medium",
      "note": "Count in the CelesTrak active satellites list, which estimates operational status."
    },
    {
      "k": "perigee_km",
      "v": [
        35761,
        35773
      ],
      "src": [
        "celestrak-gp"
      ],
      "conf": "high",
      "note": "Active satellites per CelesTrak, element epoch about 2026-11-08."
    },
    {
      "k": "apogee_km",
      "v": [
        35802,
        35811
      ],
      "src": [
        "celestrak-gp"
      ],
      "conf": "high",
      "note": "Active satellites per CelesTrak, element epoch about 2026-11-08."
    },
    {
      "k": "period_min",
      "v": 1436.1,
      "src": [
        "celestrak-gp"
      ],
      "conf": "high",
      "note": "Active satellites per CelesTrak, element epoch about 2026-11-08."
    },
    {
      "k": "inclination_deg",
      "v": [
        9.08,
        11.95
      ],
      "src": [
        "celestrak-gp"
      ],
      "conf": "high",
      "note": "Active satellites per CelesTrak, element epoch about 2026-11-08."
    }
  ],
  "payloads": [],
  "variants": [],
  "art": "satellite",
  "image": null,
  "verified": null,
  "changelog": [
    {
      "date": "2026-11-08",
      "change": "Entry created from cited open sources"
    },
    {
      "date": "2026-11-08",
      "change": "Orbital elements from CelesTrak GP data (epoch about 2026-11-08): 11 catalogued, 4 active."
    }
  ],
  "satellites": [
    {
      "name": "UFO 1 (USA 98)",
      "norad": 22563,
      "cospar": "1993-015A",
      "perigee_km": 36058,
      "apogee_km": 36091,
      "inclination_deg": 26.15,
      "period_min": 1450.8,
      "epoch": "2026-11-07",
      "active": false,
      "owner": null,
      "launch": null
    },
    {
      "name": "UFO 2 (USA 95)",
      "norad": 22787,
      "cospar": "1993-056A",
      "perigee_km": 35764,
      "apogee_km": 35808,
      "inclination_deg": 11.95,
      "period_min": 1436.1,
      "epoch": "2026-11-07",
      "active": true,
      "owner": "US",
      "launch": "1993-09-03"
    },
    {
      "name": "UFO 3 (USA 104)",
      "norad": 23132,
      "cospar": "1994-035A",
      "perigee_km": 35760,
      "apogee_km": 35813,
      "inclination_deg": 12.43,
      "period_min": 1436.1,
      "epoch": "2026-11-07",
      "active": false,
      "owner": null,
      "launch": null
    },
    {
      "name": "UFO 4 (USA 108)",
      "norad": 23467,
      "cospar": "1995-003A",
      "perigee_km": 35773,
      "apogee_km": 35802,
      "inclination_deg": 9.74,
      "period_min": 1436.1,
      "epoch": "2026-11-08",
      "active": true,
      "owner": "US",
      "launch": "1995-01-29"
    },
    {
      "name": "UFO 5 (USA 111)",
      "norad": 23589,
      "cospar": "1995-027A",
      "perigee_km": 36203,
      "apogee_km": 36233,
      "inclination_deg": 12.11,
      "period_min": 1458.2,
      "epoch": "2026-11-08",
      "active": false,
      "owner": null,
      "launch": null
    },
    {
      "name": "UFO 6 (USA 114)",
      "norad": 23696,
      "cospar": "1995-057A",
      "perigee_km": 36184,
      "apogee_km": 36246,
      "inclination_deg": 11.68,
      "period_min": 1458,
      "epoch": "2026-11-08",
      "active": false,
      "owner": null,
      "launch": null
    },
    {
      "name": "UFO 7 (USA 127)",
      "norad": 23967,
      "cospar": "1996-042A",
      "perigee_km": 35796,
      "apogee_km": 35838,
      "inclination_deg": 11.26,
      "period_min": 1437.6,
      "epoch": "2026-11-08",
      "active": false,
      "owner": null,
      "launch": null
    },
    {
      "name": "UFO 8 (USA 138)",
      "norad": 25258,
      "cospar": "1998-016A",
      "perigee_km": 35769,
      "apogee_km": 35821,
      "inclination_deg": 11.31,
      "period_min": 1436.5,
      "epoch": "2026-11-07",
      "active": false,
      "owner": null,
      "launch": null
    },
    {
      "name": "UFO 9 (USA 140)",
      "norad": 25501,
      "cospar": "1998-058A",
      "perigee_km": 36342,
      "apogee_km": 36428,
      "inclination_deg": 11.48,
      "period_min": 1466.8,
      "epoch": "2026-11-08",
      "active": false,
      "owner": null,
      "launch": null
    },
    {
      "name": "UFO 10 (USA 146)",
      "norad": 25967,
      "cospar": "1999-063A",
      "perigee_km": 35761,
      "apogee_km": 35811,
      "inclination_deg": 9.93,
      "period_min": 1436.1,
      "epoch": "2026-11-06",
      "active": true,
      "owner": "US",
      "launch": "1999-11-23"
    },
    {
      "name": "UFO 11 (USA 174)",
      "norad": 28117,
      "cospar": "2003-057A",
      "perigee_km": 35768,
      "apogee_km": 35805,
      "inclination_deg": 9.08,
      "period_min": 1436.1,
      "epoch": "2026-11-07",
      "active": true,
      "owner": "US",
      "launch": "2003-12-18"
    }
  ],
  "url": "https://www.defensepedia.com/systems/ufo.html",
  "sources": {
    "asf-ultra-high-frequency-follow-on": {
      "title": "Ultra-High Frequency Follow-On (weapons and platforms entry)",
      "publisher": "Air & Space Forces Magazine",
      "url": "https://www.airandspaceforces.com/weapons/ultra-high-frequency-follow-on/",
      "published": null,
      "tier": 3,
      "checked": "2026-11-08"
    },
    "celestrak-gp": {
      "title": "NORAD GP element sets (current data)",
      "publisher": "CelesTrak (data from the U.S. Space Force 18th/19th Space Defense Squadron catalog)",
      "url": "https://celestrak.org/NORAD/elements/",
      "published": "2026-11-08",
      "tier": 1,
      "checked": "2026-11-08"
    }
  }
}