COSMOS 2129, 21104
Orbit data source: Space-Track
COSMOS 2129, 21104 is a payload satellite owned by UNKS RF (CIS) in LEO that was launched on Tue, 12 Feb 1991 UTC via a KOSMOS 11K65M launch vehicle from the Plesetsk Missile And Space Complex (PKMTR). Payload-class satellites include a variety of spacecraft equipped with specific instruments for various scientific and technological missions. These include communications satellites like Starlink; space stations such as the ISS; scientific satellites like the Hubble; Earth observation satellites from companies like Planet Labs, Umbra, and HawkEye 360; GPS; miniature CubeSats for education and research; and military/defense satellites.
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21104 intel report (Beta)
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Identifier
Orbit
Country
CISRelated business
Manufacturer
NPO PM
Mission
Spacecraft
Bus & Motor
STRELA-1 11F625, Unknown motor
Mass
60 kg wet, 60 kg dry
Launch date (UTC)
Launch vehicle
Launch site
Object type
Shape & HBR
Unknown shape, 0.4 m
Radar Cross Section
Medium (>0.1 m² and <1 m²)
Expand to show TLE details & historyLast TLE update: 11 hours ago
TLE from 11 hours ago
0 COSMOS 2129
1 21104U 91009E 26070.86994977 -.00000008 00000-0 47803-4 0 9996
2 21104 74.0331 329.5526 0024898 158.8924 282.6153 12.53742275605329Epoch: 2026-03-11T20:52Z
TLE epoch observation values (Epoch: 2026-03-11T20:52:43.660Z)
Latitude
71.9164°
Longitude
-92.4739°
Altitude
1,456.724 km
Speed
7.142 km/s
True Right ascension
02h 00m 56s
True Declination
71° 49' 26"
Sunlit
Visualization orbit readout
Latitude
Unknown
Longitude
Unknown
Altitude
Unknown
Speed
Unknown
Apparent Right ascension
Unknown
Apparent Declination
Unknown
Sunlit
Visualization observer readout
Local Sidereal Time
12:08:45
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
1,466.194 km
Perigee altitude
1,427.229 km
Semi-major axis
7,824.848 km
Eccentricity
0.00249
Inclination
74.0331°
RAAN
329.5526°
Arg. of periapsis
158.8924°
True anomaly
282.33669°
Mean anomaly
282.6153°
Eccentric anomaly
282.47601°
Mean motion
3.13566 °/min
Orbital period
114.81 mins
BSTAR
0.000047803
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Other satellites on launch #9 in the year 1991 (1991-02-12 UTC)
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You can import UDL-sourced sensor .json files into the Sandbox to generate a visibility chart that accounts for multi-vendor sensor geometry.COSMOS 2129 Visibility forecast
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Span | Click to sort rows by Start time (UTC) header in descending order | Start Az. | Max El. time (UTC) | Max El. Az. | Max El. | End time (UTC) | End Az. |
|---|---|---|---|---|---|---|---|
| 16 mins | 2026-03-12 17:35:18.811Z | 172.399° S | 2026-03-12 17:43:18.811Z | 101.006° ESE | 37.926° | 2026-03-12 17:51:18.811Z | 29.145° NE |
| 14 mins | 2026-03-12 19:34:18.811Z | 241.007° WSW | 2026-03-12 19:40:18.811Z | 294.309° NW | 30.71° | 2026-03-12 19:48:18.811Z | 4.715° NNE |
| 15 mins | 2026-03-13 03:41:18.811Z | 353.178° N | 2026-03-13 03:48:18.811Z | 68.775° E | 38.108° | 2026-03-13 03:56:18.811Z | 139.579° SSE |
| 12 mins | 2026-03-13 05:39:18.811Z | 316.708° NNW | 2026-03-13 05:45:18.811Z | 258.98° W | 29.109° | 2026-03-13 05:51:18.811Z | 207.353° SW |
Co-orbital & Co-planar RSOs
Thresholds — Semi-major Axis: ±100 km, RAAN: ±3°, Inclination: ±5°
TCA is derived from TLE conjunctions
Click to sort rows by RSO header in ascending order | Click to sort rows by Country header in ascending order | Click to sort rows by Type header in ascending order | Click to sort rows by Inclination Δ header in ascending order | Click to sort rows by RAAN Δ header in ascending order | Click to sort rows by Coplanar Angle header in ascending order | Click to sort rows by SMA Δ header in ascending order | Click to sort rows by Orbital period header in ascending order | Click to sort rows by <5km Md TCA header in descending order |
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CAUTION: Conjunctions in this section are generated from low-fidelity TLE screenings
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