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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1806 intel report (Beta)
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Identifier
Orbit
Country
USRelated business
Manufacturer
APL
Mission
Spacecraft
Bus & Motor
DME, Unknown motor
Mass
98 kg wet, 98 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: 16 hours ago
TLE from 16 hours ago
0 EXPLORER 31 (ISIS-X)
1 01806U 65098B 26202.05892199 .00000264 00000-0 84376-4 0 9992
2 01806 79.7800 321.8817 1422459 68.2153 306.3977 12.08372865652785Epoch: 2026-07-21T01:24Z
TLE epoch observation values (Epoch: 2026-07-21T01:24:50.859Z)
Latitude
-0.00001°
Longitude
1.83573°
Altitude
1,087.846 km
Speed
7.558 km/s
True Right ascension
21h 27m 31s
True Declination
0° 00' 00"
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
06:19:58
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
2,781.726 km
Perigee altitude
500.338 km
Semi-major axis
8,019.169 km
Eccentricity
0.14225
Inclination
79.78°
RAAN
321.8817°
Arg. of periapsis
68.2153°
True anomaly
291.89639°
Mean anomaly
306.3977°
Eccentric anomaly
299.28953°
Mean motion
3.02238 °/min
Orbital period
119.11 mins
BSTAR
0.000084376
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Other satellites on launch #98 in the year 1965 (1965-11-29 UTC)
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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.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. |
|---|---|---|---|---|---|---|---|
| 13 mins | 2026-07-21 19:50:29.604Z | 347.965° N | 2026-07-21 19:54:29.604Z | 187.443° SSW | 44.791° | 2026-07-21 20:03:29.604Z | 172.143° S |
| 6 mins | 2026-07-22 09:20:29.604Z | 217.125° SW | 2026-07-22 09:23:29.604Z | 290.075° WNW | 34.534° | 2026-07-22 09:26:29.604Z | 354.602° N |
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 |
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CAUTION: Conjunctions in this section are generated from low-fidelity TLE screenings
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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 |
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