EXPLORER 20, 870
Orbit data source: Space-Track
EXPLORER 20, 870 is a payload satellite owned by GSFC (US) in LEO that was launched on Tue, 25 Aug 1964 UTC via an SCOUT X-4 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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Edit Public Description
Identifier
Orbit
Country
USRelated business
Manufacturer
Cutler-Hammer/AIL
Mission
Spacecraft
Bus & Motor
S-48, Unknown motor
Mass
44 kg wet, 44 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: 8 hours ago
TLE from 8 hours ago
0 EXPLORER 20
1 00870U 64051A 25293.27587618 .00000194 00000-0 14155-3 0 9999
2 00870 79.8994 179.8197 0096572 193.9620 165.8865 13.91724377100064Epoch: 2025-10-20T06:37Z
TLE epoch observation values (Epoch: 2025-10-20T06:37:15.701Z)
Latitude
0.00001°
Longitude
51.52376°
Altitude
993.852 km
Speed
7.32 km/s
True Right ascension
11h 59m 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
09:53:43
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
990.339 km
Perigee altitude
849.383 km
Semi-major axis
7,297.998 km
Eccentricity
0.00966
Inclination
79.8994°
RAAN
179.8197°
Arg. of periapsis
193.962°
True anomaly
166.15322°
Mean anomaly
165.8865°
Eccentric anomaly
166.02017°
Mean motion
3.48127 °/min
Orbital period
103.41 mins
BSTAR
0.00014155
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Other satellites on launch #51 in the year 1964 (1964-08-25 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 20 Visibility forecast
Loading observer location...
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. |
|---|---|---|---|---|---|---|---|
| 11 mins | 2025-10-20 17:04:54.320Z | 171.28° S | 2025-10-20 17:09:54.320Z | 104.241° ESE | 40.404° | 2025-10-20 17:15:54.320Z | 19.714° NNE |
| 7 mins | 2025-10-20 18:51:54.320Z | 256.222° W | 2025-10-20 18:54:54.320Z | 290.55° WNW | 20.308° | 2025-10-20 18:58:54.320Z | 335.927° NNW |
| 10 mins | 2025-10-21 03:54:54.320Z | 359.287° N | 2025-10-21 03:59:54.320Z | 88.541° E | 40.214° | 2025-10-21 04:04:54.320Z | 154.484° SSE |
| 5 mins | 2025-10-21 05:41:54.320Z | 295.069° NW | 2025-10-21 05:43:54.320Z | 270.335° WNW | 16.569° | 2025-10-21 05:46:54.320Z | 236.878° WSW |
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 ascending order |
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CAUTION: Conjunctions in this section are generated from low-fidelity TLE screenings
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