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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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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: 13 hours ago

TLE from 13 hours ago

0 CALSPHERE 4(A)
1 01520U 65065H   26042.58695576  .00000089  00000-0  15203-3 0  9996
2 01520  89.9083 123.7108 0071720  98.4338  10.3781 13.36254295945931

Epoch: 2026-02-11T14:05Z

TLE epoch observation values (Epoch: 2026-02-11T14:05:12.977Z)

Latitude

71.10572°

Longitude

-49.51075°

Altitude

1,082.714 km

Speed

7.343 km/s

True Right ascension

20h 13m 46s

True Declination

71° 00' 17"

Sunlit

Object was in daylight 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

05:12:37

Azimuth

Unknown

Elevation

Unknown

Doppler factor

Unknown

Orbital elements

Apogee altitude

1,174.114 km

Perigee altitude

1,066.556 km

Semi-major axis

7,498.472 km

Eccentricity

0.00717

Inclination

89.9083°

RAAN

123.7108°

Arg. of periapsis

98.4338°

True anomaly

10.52747°

Mean anomaly

10.3781°

Eccentric anomaly

10.45265°

Mean motion

3.3426 °/min

Orbital period

107.7 mins

BSTAR

0.00015203

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

THOR ABLESTAR DEB, 6290 (Decayed)

TRANSIT 5B-7 DEB, 3809 (Decayed)

THOR ABLESTAR DEB, 1521

THOR ABLESTAR DEB, 5265

OPS 8464 (TRANSIT 5B-7), 1514

OPS 8464 DEB *, 2335 (Decayed)

THOR ABLESTAR DEB, 3810

THOR ABLESTAR DEB, 1511

NAVSPASUR ROD 1, 1515

THOR ABLESTAR R/B, 1508

THOR ABLESTAR DEB, 1504

TEMPSAT 1, 1512

DODECAPOLE 2, 1510

DODECAPOLE 2 DEB, 41734

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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.
6 mins	2026-02-12 04:05:25.181Z	100.265° ESE	2026-02-12 04:08:25.181Z	71.38° E	15.747°	2026-02-12 04:11:25.181Z	42.096° NE
12 mins	2026-02-12 05:49:25.181Z	182.23° SSW	2026-02-12 05:55:25.181Z	290.997° WNW	44.326°	2026-02-12 06:01:25.181Z	354.993° N
11 mins	2026-02-12 17:06:25.181Z	15.051° NNE	2026-02-12 17:11:25.181Z	75.105° E	38.137°	2026-02-12 17:17:25.181Z	161.274° S
8 mins	2026-02-12 18:55:25.181Z	325.669° NNW	2026-02-12 18:59:25.181Z	279.127° WNW	22.534°	2026-02-12 19:03:25.181Z	238.456° WSW

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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: 13 hours ago

TLE from 13 hours ago

TLE epoch observation values (Epoch: 2026-02-11T14:05:12.977Z)

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: 13 hours ago