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: 12 hours ago
TLE from 12 hours ago
0 CALSPHERE 4(A)
1 01520U 65065H 25260.96132128 .00000106 00000-0 18582-3 0 9991
2 01520 89.9142 124.9909 0070097 150.5156 277.0700 13.36215787926354Epoch: 2025-09-17T23:04Z
TLE epoch observation values (Epoch: 2025-09-17T23:04:18.158Z)
Latitude
66.86475°
Longitude
141.98527°
Altitude
1,128.948 km
Speed
7.297 km/s
True Right ascension
08h 20m 45s
True Declination
66° 44' 47"
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
03:59:15
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
1,173.042 km
Perigee altitude
1,067.916 km
Semi-major axis
7,498.616 km
Eccentricity
0.00701
Inclination
89.9142°
RAAN
124.9909°
Arg. of periapsis
150.5156°
True anomaly
276.27202°
Mean anomaly
277.07°
Eccentric anomaly
276.67109°
Mean motion
3.3425 °/min
Orbital period
107.7 mins
BSTAR
0.00018582
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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. |
|---|---|---|---|---|---|---|---|
| 13 mins | 2025-09-18 15:00:13.222Z | 161.607° S | 2025-09-18 15:07:13.222Z | 66.58° ENE | 41.408° | 2025-09-18 15:13:13.222Z | 5.331° NNE |
| 8 mins | 2025-09-18 16:51:13.222Z | 243.064° WSW | 2025-09-18 16:55:13.222Z | 284.878° WNW | 20.2° | 2025-09-18 16:59:13.222Z | 323.827° NNW |
| 9 mins | 2025-09-19 02:19:13.222Z | 32.459° NE | 2025-09-19 02:23:13.222Z | 80.355° E | 26.499° | 2025-09-19 02:28:13.222Z | 137.72° SSE |
| 10 mins | 2025-09-19 04:06:13.222Z | 342.874° N | 2025-09-19 04:11:13.222Z | 276.106° WNW | 33.773° | 2025-09-19 04:16:13.222Z | 215.827° 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 ascending order |
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CAUTION: Conjunctions in this section are generated from low-fidelity TLE screenings
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