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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Edit Public Description
Identifier
Orbit
Country
USRelated business
Manufacturer
APL
Mission
Civil Science
Bus & Motor
DME, Unknown motor
Mass
98 kg wet, 98 kg dry
Launch date (UTC)
Launch vehicle
Launch site
Object type
Shape & HBR
Oct Cyl, 0.5 m
Radar Cross Section
0.700 m², Medium (>0.1 m² and < 1m²)
Expand to show TLE details & historyLast TLE update: 9 hours ago
TLE from 9 hours ago
0 EXPLORER 31 (ISIS-X)
1 01806U 65098B 25261.26097696 .00001123 00000-0 39477-3 0 9994
2 01806 79.7764 214.0496 1423876 307.5329 40.4423 12.08009721615855Epoch: 2025-09-18T06:15Z
TLE epoch observation values (Epoch: 2025-09-18T06:15:48.409Z)
Latitude
0.00007°
Longitude
122.67279°
Altitude
859.156 km
Speed
7.779 km/s
True Right ascension
14h 16m 11s
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
07:49:51
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
2,784.699 km
Perigee altitude
500.581 km
Semi-major axis
8,020.777 km
Eccentricity
0.14239
Inclination
79.7764°
RAAN
214.0496°
Arg. of periapsis
307.5329°
True anomaly
52.57971°
Mean anomaly
40.4423°
Eccentric anomaly
46.34482°
Mean motion
3.02147 °/min
Orbital period
119.15 mins
BSTAR
0.00039477
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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 | 2025-09-18 20:18:11.889Z | 121.493° SE | 2025-09-18 20:23:11.889Z | 77.204° E | 23.419° | 2025-09-18 20:31:11.889Z | 29.369° NE |
| 18 mins | 2025-09-18 22:16:11.889Z | 206.752° SW | 2025-09-18 22:22:11.889Z | 282.008° WNW | 42.672° | 2025-09-18 22:34:11.889Z | 8.753° NNE |
| 11 mins | 2025-09-19 00:22:11.889Z | 288.179° WNW | 2025-09-19 00:27:11.889Z | 320.637° NNW | 16.01° | 2025-09-19 00:33:11.889Z | 350.729° N |
| 25 mins | 2025-09-19 06:43:11.889Z | 2.188° NNE | 2025-09-19 06:55:11.889Z | 59.631° ENE | 30.879° | 2025-09-19 07:08:11.889Z | 122.779° SE |
| 28 mins | 2025-09-19 08:43:11.889Z | 346.77° N | 2025-09-19 08:58:11.889Z | 248.233° W | 44.66° | 2025-09-19 09:11:11.889Z | 179.189° S |
| 20 mins | 2025-09-19 10:46:11.889Z | 327.561° NNW | 2025-09-19 10:56:11.889Z | 285.206° WNW | 23.293° | 2025-09-19 11:06:11.889Z | 239.885° WSW |
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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