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 Defense Calibration
Bus & Motor
NRL 14", Unknown motor
Mass
4 kg wet, 4 kg dry
Launch date (UTC)
Launch vehicle
Launch site
Object type
Shape & HBR
Sphere, 0.2 m
Radar Cross Section
0.126 m², Small (<0.1 m²)
Expand to show TLE details & historyLast TLE update: 1 day ago
TLE from 1 day ago
0 CALSPHERE 4(A)
1 01520U 65065H 25260.08079406 .00000099 00000-0 17069-3 0 9993
2 01520 89.9144 124.9983 0070017 152.9758 1.4273 13.36215598926235Epoch: 2025-09-17T01:56Z
TLE epoch observation values (Epoch: 2025-09-17T01:56:20.606Z)
Latitude
25.60569°
Longitude
-80.39024°
Altitude
1,074.036 km
Speed
7.343 km/s
True Right ascension
20h 19m 49s
True Declination
25° 28' 39"
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
20:52:45
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
1,172.983 km
Perigee altitude
1,067.976 km
Semi-major axis
7,498.616 km
Eccentricity
0.007
Inclination
89.9144°
RAAN
124.9983°
Arg. of periapsis
152.9758°
True anomaly
1.44746°
Mean anomaly
1.4273°
Eccentric anomaly
1.43736°
Mean motion
3.3425 °/min
Orbital period
107.7 mins
BSTAR
0.00017069
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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. |
|---|---|---|---|---|---|---|---|
| 9 mins | 2025-09-18 04:43:53.467Z | 334.822° NNW | 2025-09-18 04:48:53.467Z | 284.956° WNW | 21.543° | 2025-09-18 04:52:53.467Z | 242.476° WSW |
| 11 mins | 2025-09-18 15:01:53.467Z | 158.031° S | 2025-09-18 15:06:53.467Z | 80.518° E | 41.676° | 2025-09-18 15:12:53.467Z | 5.899° NNE |
| 9 mins | 2025-09-18 16:50:53.467Z | 240.536° WSW | 2025-09-18 16:54:53.467Z | 280.974° WNW | 20.276° | 2025-09-18 16:59:53.467Z | 328.283° NNW |
| 10 mins | 2025-09-19 02:18:53.467Z | 30.163° NE | 2025-09-19 02:22:53.467Z | 75.102° E | 26.322° | 2025-09-19 02:28:53.467Z | 141.468° SSE |
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 ascending order |
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CAUTION: Conjunctions in this section are generated from low-fidelity TLE screenings
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