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: 13 hours ago
TLE from 13 hours ago
0 EXPLORER 31 (ISIS-X)
1 01806U 65098B 26142.11180675 -.00000125 00000-0 -46652-4 0 9994
2 01806 79.7769 11.3199 1423161 185.6755 172.6546 12.08306238645549Epoch: 2026-05-22T02:41Z
TLE epoch observation values (Epoch: 2026-05-22T02:41:00.103Z)
Latitude
0.00005°
Longitude
91.32214°
Altitude
2,781.163 km
Speed
6.114 km/s
True Right ascension
00h 45m 16s
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
00:23:33
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
2,782.626 km
Perigee altitude
500.028 km
Semi-major axis
8,019.464 km
Eccentricity
0.14232
Inclination
79.7769°
RAAN
11.3199°
Arg. of periapsis
185.6755°
True anomaly
174.42523°
Mean anomaly
172.6546°
Eccentric anomaly
173.56805°
Mean motion
3.02221 °/min
Orbital period
119.12 mins
BSTAR
-0.000046652
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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. |
|---|---|---|---|---|---|---|---|
| 26 mins | 2026-05-22 16:38:57.143Z | 202.785° SW | 2026-05-22 16:53:57.143Z | 289.83° WNW | 42.538° | 2026-05-22 17:04:57.143Z | 5.235° NNE |
| 14 mins | 2026-05-22 18:48:57.143Z | 268.973° W | 2026-05-22 18:55:57.143Z | 300.625° NW | 17.933° | 2026-05-22 19:02:57.143Z | 338.408° N |
| 8 mins | 2026-05-23 03:17:57.143Z | 339.713° N | 2026-05-23 03:21:57.143Z | 270.55° WNW | 41.198° | 2026-05-23 03:25:57.143Z | 184.91° SSW |
| 22 mins | 2026-05-23 14:31:57.143Z | 146.954° SSE | 2026-05-23 14:43:57.143Z | 90.063° ESE | 32.941° | 2026-05-23 14:53:57.143Z | 29.041° NE |
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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