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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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Iframe URL

https://www.satcat.com/sats-embedded/1520?theme=dark&initialShowStats=false

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Identifier

1520, 1965-065H

Orbit

LEO

Country

Related business

United States Navy (US)

Manufacturer

NRL

Mission

Operational spacecraft

Bus & Motor

NRL 14", Unknown motor

Mass

4 kg wet, 4 kg dry

Launch date (UTC)

1965-08-13 (61 years ago)

Launch vehicle

THOR ABLESTAR

Launch site

Air Force Western Test Range (AFWTR)

Object type

Payload

Rocket body

Debris

Shape & HBR

Unknown

Radar Cross Section

Small (<0.1 m²)

Expand to show TLE details & history
Last TLE update: 8 hours ago

TLE from 8 hours ago

0 CALSPHERE 4(A)
1 01520U 65065H   26043.92319352  .00000085  00000-0  14440-3 0  9998
2 01520  89.9080 123.6989 0071704  94.7641 318.2695 13.36254520946118

Epoch: 2026-02-12T22:09Z

TLE epoch observation values (Epoch: 2026-02-12T22:09:23.920Z)

Latitude

52.57713°

Longitude

8.50086°

Altitude

1,091.902 km

Speed

7.331 km/s

True Right ascension

08h 15m 16s

True Declination

52° 25' 06"

Sunlit

Object was in full shadow at epoch

Visualization orbit readout

Latitude

Unknown

Longitude

Unknown

Altitude

Unknown

Speed

Unknown

Apparent Right ascension

Unknown

Apparent Declination

Unknown

Sunlit

N/A

Visualization observer readout

Local Sidereal Time

08:43:02

Azimuth

Unknown

Elevation

Unknown

Doppler factor

Unknown

Orbital elements

Apogee altitude

1,174.101 km

Perigee altitude

1,066.567 km

Semi-major axis

7,498.471 km

Eccentricity

0.00717

Inclination

89.908°

RAAN

123.6989°

Arg. of periapsis

94.7641°

True anomaly

317.7189°

Mean anomaly

318.2695°

Eccentric anomaly

317.99457°

Mean motion

3.3426 °/min

Orbital period

107.7 mins

BSTAR

0.0001444

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Other satellites on launch #65 in the year 1965 (1965-08-13 UTC)

THOR ABLESTAR DEB, 1521

THOR ABLESTAR DEB, 5363 (Decayed)

THOR ABLESTAR DEB, 5265

THOR ABLESTAR DEB, 1522

PORCUPINE 2, 1577

OPS 8464 (TRANSIT 5B-7), 1514

DODECAPOLE 2, 1510

DODECAPOLE 2 DEB, 41734

TEMPSAT 1, 1512

THOR ABLESTAR DEB, 1504

THOR ABLESTAR DEB, 3810

NAVSPASUR ROD 1, 1515

THOR ABLESTAR DEB, 1511

THOR ABLESTAR DEB, 6290 (Decayed)

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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	2026-02-13 07:00:19.841Z	233.354° WSW	2026-02-13 07:05:19.841Z	283.197° WNW	20.3°	2026-02-13 07:09:19.841Z	323.853° NNW
9 mins	2026-02-13 16:29:19.841Z	33.825° NE	2026-02-13 16:33:19.841Z	81.093° E	25.72°	2026-02-13 16:38:19.841Z	136.322° SSE
11 mins	2026-02-13 18:16:19.841Z	343.704° N	2026-02-13 18:21:19.841Z	274.757° WNW	35.016°	2026-02-13 18:27:19.841Z	210.418° SW
9 mins	2026-02-14 04:35:19.841Z	126.427° SE	2026-02-14 04:39:19.841Z	74.828° E	28.313°	2026-02-14 04:44:19.841Z	20.1° NNE

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Co-orbital & Co-planar RSOs

Thresholds — Semi-major Axis: ±100 km, RAAN: ±3°, Inclination: ±5°
TCA is derived from TLE conjunctions

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CAUTION: Conjunctions in this section are generated from low-fidelity TLE screenings

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Check out CALSPHERE 4(A), 1520 on other resources

View CALSPHERE 4(A), 1520 on NASA - NSSDCA Website

View CALSPHERE 4(A), 1520 on Heavens-Above

View CALSPHERE 4(A), 1520 on Keep Track

View CALSPHERE 4(A), 1520 on Celestrak

View CALSPHERE 4(A), 1520 on Gunter's Space Page

Satcat and Kayhan Space are not affiliated with NASA, Celestrak, Heavens-Above, Keep Track, or Gunter's Space Page.

CALSPHERE 4(A), 1520

Orbit data source: Space-Track

Expand to show TLE details & historyLast TLE update: 8 hours ago

TLE from 8 hours ago

TLE epoch observation values (Epoch: 2026-02-12T22:09:23.920Z)

Visualization orbit readout

Visualization observer readout

Orbital elements

Other satellites on launch #65 in the year 1965 (1965-08-13 UTC)

CALSPHERE 4(A) Visibility forecast

Co-orbital & Co-planar RSOs

Check out CALSPHERE 4(A), 1520 on other resources

Documentation

Expand to show TLE details & history
Last TLE update: 8 hours ago