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.
Focus sentinelFocus sentinel
Request partner network tasking
Focus sentinelFocus sentinel
Embed this page
Focus sentinelFocus sentinel
1520 intel report (Beta)
Focus sentinelFocus sentinel
Edit Public Description
Focus sentinelFocus sentinel
Edit Sat Name
Focus sentinelFocus sentinel
Create New Watchlist
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: 17 hours ago
TLE from 17 hours ago
0 CALSPHERE 4(A)
1 01520U 65065H 26179.82929887 .00000089 00000-0 15254-3 0 9995
2 01520 89.8988 122.3732 0072124 71.0203 343.2619 13.36280464964261Epoch: 2026-06-28T19:54Z
TLE epoch observation values (Epoch: 2026-06-28T19:54:11.422Z)
Latitude
54.13625°
Longitude
-92.95861°
Altitude
1,080.354 km
Speed
7.342 km/s
True Right ascension
08h 10m 02s
True Declination
53° 58' 48"
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
00:00:32
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
1,174.318 km
Perigee altitude
1,066.155 km
Semi-major axis
7,498.374 km
Eccentricity
0.00721
Inclination
89.8988°
RAAN
122.3732°
Arg. of periapsis
71.0203°
True anomaly
343.0218°
Mean anomaly
343.2619°
Eccentric anomaly
343.14206°
Mean motion
3.34266 °/min
Orbital period
107.7 mins
BSTAR
0.00015254
Loading maneuver chart data...
Computing Atmospheric mass density...
Loading historical data...
Loading historical data...
Loading historical data...
Loading historical data...
Loading historical data...
Loading historical data...
Loading historical data...
Other satellites on launch #65 in the year 1965 (1965-08-13 UTC)
Did you know?
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
Loading observer location...
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 | 2026-06-29 19:08:35.516Z | 112.963° SE | 2026-06-29 19:12:35.516Z | 72.739° E | 19.027° | 2026-06-29 19:16:35.516Z | 32.497° NE |
| 11 mins | 2026-06-29 20:54:35.516Z | 192.824° SSW | 2026-06-29 20:59:35.516Z | 273.453° WNW | 41.831° | 2026-06-29 21:05:35.516Z | 350.673° N |
| 12 mins | 2026-06-30 08:10:35.516Z | 9.976° NNE | 2026-06-30 08:16:35.516Z | 109.905° ESE | 42.018° | 2026-06-30 08:22:35.516Z | 171.325° S |
| 8 mins | 2026-06-30 09:59:35.516Z | 323.323° NNW | 2026-06-30 10:03:35.516Z | 281.58° WNW | 19.015° | 2026-06-30 10:07:35.516Z | 244.5° 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 |
|---|
CAUTION: Conjunctions in this section are generated from low-fidelity TLE screenings
Authenticating...
Click to sort rows by Secondary header in ascending order | Click to sort rows by Secondary name header in ascending order | Click to sort rows by Country header in ascending order | Click to sort rows by Owner header in ascending order | Click to sort rows by Obj. Type header in ascending order | Click to sort rows by Miss dist. header in ascending order | Click to sort rows by Rel. speed header in ascending order | Click to sort rows by Apr. angle header in ascending order | Click to sort rows by TCA header in descending order |
|---|