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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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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: 10 hours ago

TLE from 10 hours ago

0 EXPLORER 31 (ISIS-X)
1  1806U 65098B   26112.05342785  .00000509  00000-0  17937-3 0  9993
2  1806  79.7856  36.1108 1422639 244.6020 100.1291 12.08320575641911

Epoch: 2026-04-22T01:16Z

TLE epoch observation values (Epoch: 2026-04-22T01:16:56.166Z)

Latitude

0.00002°

Longitude

166.7564°

Altitude

1,996.949 km

Speed

6.748 km/s

True Right ascension

02h 24m 26s

True Declination

0° 00' 00"

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

18:17:46

Azimuth

Unknown

Elevation

Unknown

Doppler factor

Unknown

Orbital elements

Apogee altitude

2,782.134 km

Perigee altitude

500.392 km

Semi-major axis

8,019.4 km

Eccentricity

0.14226

Inclination

79.7856°

RAAN

36.1108°

Arg. of periapsis

244.602°

True anomaly

115.50431°

Mean anomaly

100.1291°

Eccentric anomaly

107.88626°

Mean motion

3.02225 °/min

Orbital period

119.12 mins

BSTAR

0.00017937

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

THOR AGENA B DEB, 1944 (Decayed)

THOR AGENA B DEB, 2092

THOR AGENA B R/B, 1807

THOR AGENA B DEB, 2153

ALOUETTE 2, 1804

THOR AGENA B DEB, 1951

THOR AGENA B DEB, 1948

THOR AGENA B DEB, 1808 (Decayed)

ALOUETTE 2 DEB, 20833 (Decayed)

ALOUETTE 2 DEB, 25058 (Decayed)

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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.
17 mins	2026-04-22 17:20:07.804Z	108.68° ESE	2026-04-22 17:28:07.804Z	72.369° E	19.709°	2026-04-22 17:37:07.804Z	35.245° NE
27 mins	2026-04-22 19:14:07.804Z	173.601° S	2026-04-22 19:26:07.804Z	90.484° ESE	43.664°	2026-04-22 19:41:07.804Z	14.707° NNE
25 mins	2026-04-22 21:17:07.804Z	235.967° WSW	2026-04-22 21:28:07.804Z	297.879° NW	33.416°	2026-04-22 21:42:07.804Z	2.935° NNE
9 mins	2026-04-22 23:31:07.804Z	310.49° NW	2026-04-22 23:35:07.804Z	326.173° NNW	12.358°	2026-04-22 23:40:07.804Z	345.605° N
11 mins	2026-04-23 03:51:07.804Z	11.818° NNE	2026-04-23 03:57:07.804Z	40.831° NE	15.412°	2026-04-23 04:02:07.804Z	69.764° E
18 mins	2026-04-23 05:51:07.804Z	354.771° N	2026-04-23 06:02:07.804Z	74.41° E	40.652°	2026-04-23 06:09:07.804Z	146.755° SSE
15 mins	2026-04-23 07:53:07.804Z	332.137° NNW	2026-04-23 08:01:07.804Z	284.808° WNW	28.872°	2026-04-23 08:08:07.804Z	223.403° SW

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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: 10 hours ago

TLE from 10 hours ago

TLE epoch observation values (Epoch: 2026-04-22T01:16:56.166Z)

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: 10 hours ago