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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Edit Public Description
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: 22 hours ago
TLE from 22 hours ago
0 CALSPHERE 4(A)
1 01520U 65065H 25347.17230631 .00000156 00000-0 28406-3 0 9999
2 01520 89.9097 124.2369 0068221 268.3406 266.9124 13.36239789937861Epoch: 2025-12-13T04:08Z
TLE epoch observation values (Epoch: 2025-12-13T04:08:07.265Z)
Latitude
5.44533°
Longitude
160.09467°
Altitude
1,128.817 km
Speed
7.287 km/s
True Right ascension
20h 16m 54s
True Declination
5° 24' 52"
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
00:14:01
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
1,171.545 km
Perigee altitude
1,069.233 km
Semi-major axis
7,498.526 km
Eccentricity
0.00682
Inclination
89.9097°
RAAN
124.2369°
Arg. of periapsis
268.3406°
True anomaly
266.13216°
Mean anomaly
266.9124°
Eccentric anomaly
266.52224°
Mean motion
3.34256 °/min
Orbital period
107.7 mins
BSTAR
0.00028406
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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. |
|---|---|---|---|---|---|---|---|
| 8 mins | 2025-12-14 08:09:32.571Z | 110.716° ESE | 2025-12-14 08:13:32.571Z | 72.983° E | 18.985° | 2025-12-14 08:17:32.571Z | 34.473° NE |
| 13 mins | 2025-12-14 09:54:32.571Z | 187.156° SSW | 2025-12-14 10:00:32.571Z | 273.854° WNW | 43.299° | 2025-12-14 10:07:32.571Z | 353.544° N |
| 12 mins | 2025-12-14 21:12:32.571Z | 12.653° NNE | 2025-12-14 21:17:32.571Z | 76.262° E | 41.212° | 2025-12-14 21:24:32.571Z | 169.093° S |
| 8 mins | 2025-12-14 23:01:32.571Z | 321.826° NNW | 2025-12-14 23:04:32.571Z | 290.299° WNW | 21.214° | 2025-12-14 23:09:32.571Z | 241.433° WSW |
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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