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
Medium (>0.1 m² and <1 m²)
Expand to show TLE details & historyLast TLE update: 10 hours ago
TLE from 10 hours ago
0 CALSPHERE 4(A)
1 1520U 65065H 26199.82518549 .00000084 00000-0 14424-3 0 9999
2 1520 89.8987 122.1769 0070922 15.9472 54.4242 13.36283641966936Epoch: 2026-07-18T19:48Z
TLE epoch observation values (Epoch: 2026-07-18T19:48:16.026Z)
Latitude
71.10248°
Longitude
-111.22786°
Altitude
1,104.815 km
Speed
7.321 km/s
True Right ascension
08h 09m 53s
True Declination
71° 00' 06"
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
18:55:59
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
1,173.405 km
Perigee altitude
1,067.045 km
Semi-major axis
7,498.362 km
Eccentricity
0.00709
Inclination
89.8987°
RAAN
122.1769°
Arg. of periapsis
15.9472°
True anomaly
55.08862°
Mean anomaly
54.4242°
Eccentric anomaly
54.75607°
Mean motion
3.34267 °/min
Orbital period
107.7 mins
BSTAR
0.00014424
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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 | 2026-07-19 06:49:13.916Z | 9.411° NNE | 2026-07-19 06:56:13.916Z | 101.405° ESE | 41.1° | 2026-07-19 07:02:13.916Z | 167.947° S |
| 8 mins | 2026-07-19 08:39:13.916Z | 324.983° NNW | 2026-07-19 08:43:13.916Z | 282.639° WNW | 21.334° | 2026-07-19 08:47:13.916Z | 243.706° WSW |
| 11 mins | 2026-07-19 18:56:13.916Z | 160.967° S | 2026-07-19 19:01:13.916Z | 63.362° ENE | 42.256° | 2026-07-19 19:07:13.916Z | 3.896° NNE |
| 7 mins | 2026-07-19 20:46:13.916Z | 252.565° W | 2026-07-19 20:49:13.916Z | 284.703° WNW | 17.831° | 2026-07-19 20:53:13.916Z | 323.141° NNW |
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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