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EXPLORER 31 (ISIS-X), 1806

Orbit data source: Space-Track

EXPLORER 31 (ISIS-X), 1806 is a payload satellite owned by GSFC (US) in LEO that was launched on Mon, 29 Nov 1965 UTC via a THOR SLV-2 AGENA B 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/1806?theme=dark&initialShowStats=false

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Identifier

1806, 1965-098B

Orbit

LEO

Country

Related business

National Aeronautics and Space Administration (NASA) (US)

Manufacturer

APL

Mission

Spacecraft

Bus & Motor

DME, Unknown motor

Mass

98 kg wet, 98 kg dry

Launch date (UTC)

1965-11-29 (60 years ago)

Launch vehicle

THOR SLV-2 AGENA B

Launch site

Air Force Western Test Range (AFWTR)

Object type

Payload

Rocket body

Debris

Shape & HBR

Unknown

Radar Cross Section

Medium (>0.1 m² and <1 m²)

Expand to show TLE details & history
Last TLE update: 12 hours ago

TLE from 12 hours ago

0 EXPLORER 31 (ISIS-X)
1 01806U 65098B   26038.20090226  .00001021  00000-0  35008-3 0  9996
2 01806  79.7750  97.0452 1423939  29.3703 338.0244 12.08223725632999

Epoch: 2026-02-07T04:49Z

TLE epoch observation values (Epoch: 2026-02-07T04:49:17.955Z)

Latitude

0.00003°

Longitude

-112.60744°

Altitude

615.468 km

Speed

8.022 km/s

True Right ascension

06h 28m 10s

True Declination

0° 00' 00"

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

19:24:32

Azimuth

Unknown

Elevation

Unknown

Doppler factor

Unknown

Orbital elements

Apogee altitude

2,783.667 km

Perigee altitude

499.718 km

Semi-major axis

8,019.829 km

Eccentricity

0.14239

Inclination

79.775°

RAAN

97.0452°

Arg. of periapsis

29.3703°

True anomaly

330.74295°

Mean anomaly

338.0244°

Eccentric anomaly

334.51382°

Mean motion

3.02201 °/min

Orbital period

119.13 mins

BSTAR

0.00035008

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Other satellites on launch #98 in the year 1965 (1965-11-29 UTC)

THOR AGENA B DEB, 1944 (Decayed)

ALOUETTE 2 DEB, 25058 (Decayed)

THOR AGENA B DEB, 1948

THOR AGENA B DEB, 1951

THOR AGENA B R/B, 1807

ALOUETTE 2, 1804

THOR AGENA B DEB, 2153

THOR AGENA B DEB, 2092

ALOUETTE 2 DEB, 20833 (Decayed)

THOR AGENA B DEB, 1808 (Decayed)

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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.

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EXPLORER 31 (ISIS-X) 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.
16 mins	2026-02-07 17:17:39.524Z	317.751° NNW	2026-02-07 17:24:39.524Z	266.294° W	24.867°	2026-02-07 17:33:39.524Z	221.63° SW
6 mins	2026-02-08 04:47:39.524Z	194.526° SSW	2026-02-08 04:49:39.524Z	211.717° SW	42.732°	2026-02-08 04:53:39.524Z	9.361° NNE
10 mins	2026-02-08 13:09:39.524Z	39.191° NE	2026-02-08 13:13:39.524Z	66.728° ENE	16.171°	2026-02-08 13:19:39.524Z	98.245° ESE
20 mins	2026-02-08 15:07:39.524Z	355.832° N	2026-02-08 15:14:39.524Z	81.128° E	43.932°	2026-02-08 15:27:39.524Z	163.706° S
5 mins	2026-02-08 17:08:39.524Z	317.172° NNW	2026-02-08 17:13:39.524Z	281.584° WNW	25.171°	2026-02-08 17:13:39.524Z	281.584° WNW

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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 EXPLORER 31 (ISIS-X), 1806 on other resources

View EXPLORER 31 (ISIS-X), 1806 on NASA - NSSDCA Website

View EXPLORER 31 (ISIS-X), 1806 on Heavens-Above

View EXPLORER 31 (ISIS-X), 1806 on Keep Track

View EXPLORER 31 (ISIS-X), 1806 on Celestrak

View EXPLORER 31 (ISIS-X), 1806 on Gunter's Space Page

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

EXPLORER 31 (ISIS-X), 1806

Orbit data source: Space-Track

Expand to show TLE details & historyLast TLE update: 12 hours ago

TLE from 12 hours ago

TLE epoch observation values (Epoch: 2026-02-07T04:49:17.955Z)

Visualization orbit readout

Visualization observer readout

Orbital elements

Other satellites on launch #98 in the year 1965 (1965-11-29 UTC)

EXPLORER 31 (ISIS-X) Visibility forecast

Co-orbital & Co-planar RSOs

Check out EXPLORER 31 (ISIS-X), 1806 on other resources

Documentation

Expand to show TLE details & history
Last TLE update: 12 hours ago