CALSPHERE 4(A), 1520
Orbit data source: Space-Track
CALSPHERE 4(A), 1520 is a payload satellite owned by NRL (US) in LEO that was launched on Fri, 13 Aug 1965 UTC via a THOR ABLESTAR launch vehicle from the Air Force Western Test Range (AFWTR). 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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1520 intel report (Beta)
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Identifier
Orbit
Country
USRelated business
Manufacturer
NRL
Mission
Operational spacecraft
Bus & Motor
NRL 14", Unknown motor
Mass
4 kg wet, 4 kg dry
Launch date (UTC)
Launch vehicle
Launch site
Object type
Shape & HBR
Unknown
Radar Cross Section
Small (<0.1 m²)
Expand to show TLE details & historyLast TLE update: 7 hours ago
TLE from 7 hours ago
0 CALSPHERE 4(A)
1 1520U 65065H 26132.80970787 .00000101 00000-0 17606-3 0 9995
2 1520 89.8963 122.8393 0068838 201.8130 233.0602 13.36271517957989Epoch: 2026-05-12T19:25Z
TLE epoch observation values (Epoch: 2026-05-12T19:25:58.759Z)
Latitude
74.30246°
Longitude
-38.86717°
Altitude
1,167.294 km
Speed
7.261 km/s
True Right ascension
08h 12m 49s
True Declination
74° 13' 03"
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
10:52:11
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
1,171.888 km
Perigee altitude
1,068.653 km
Semi-major axis
7,498.407 km
Eccentricity
0.00688
Inclination
89.8963°
RAAN
122.8393°
Arg. of periapsis
201.813°
True anomaly
232.43297°
Mean anomaly
233.0602°
Eccentric anomaly
232.74626°
Mean motion
3.34264 °/min
Orbital period
107.7 mins
BSTAR
0.00017606
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Other satellites on launch #65 in the year 1965 (1965-08-13 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.CALSPHERE 4(A) 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. |
|---|---|---|---|---|---|---|---|
| 7 mins | 2026-05-13 10:04:11.691Z | 42.697° NE | 2026-05-13 10:08:11.691Z | 80.721° E | 15.607° | 2026-05-13 10:11:11.691Z | 108.987° ESE |
| 11 mins | 2026-05-13 11:51:11.691Z | 357.577° N | 2026-05-13 11:56:11.691Z | 265.801° W | 44.296° | 2026-05-13 12:02:11.691Z | 190.459° SSW |
| 8 mins | 2026-05-13 22:10:11.691Z | 108.03° ESE | 2026-05-13 22:14:11.691Z | 69.244° E | 18.974° | 2026-05-13 22:18:11.691Z | 32.238° NE |
| 12 mins | 2026-05-13 23:55:11.691Z | 187.485° SSW | 2026-05-14 00:01:11.691Z | 293.918° NW | 43.111° | 2026-05-14 00:07:11.691Z | 352.764° N |
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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