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
Civil Science
Bus & Motor
S-48, Unknown motor
Mass
44 kg wet, 44 kg dry
Launch date (UTC)
Launch vehicle
Launch site
Object type
Shape & HBR
Double Cone + 6 Rod, 18.5 m
Radar Cross Section
0.292 m², Medium (>0.1 m² and < 1m²)
Expand to show TLE details & historyLast TLE update: 21 hours ago
TLE from 21 hours ago
0 EXPLORER 20
1 00870U 64051A 25242.23286719 .00000189 00000-0 13785-3 0 9999
2 00870 79.8950 235.3530 0096652 328.9400 30.6062 13.91706271 92960Epoch: 2025-08-30T05:35Z
TLE epoch observation values (Epoch: 2025-08-30T05:35:19.725Z)
Latitude
-0.00003°
Longitude
172.8507°
Altitude
864.92 km
Speed
7.451 km/s
True Right ascension
15h 41m 24s
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
18:33:44
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
990.462 km
Perigee altitude
849.387 km
Semi-major axis
7,298.062 km
Eccentricity
0.00967
Inclination
79.895°
RAAN
235.353°
Arg. of periapsis
328.94°
True anomaly
31.17601°
Mean anomaly
30.6062°
Eccentric anomaly
30.89051°
Mean motion
3.48122 °/min
Orbital period
103.41 mins
BSTAR
0.00013785
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Other satellites on launch #51 in the year 1964 (1964-08-25 UTC)
EXPLORER 20 Visibility forecast
Observer location: undefined°, undefined°
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. |
|---|---|---|---|---|---|---|---|
| 7 mins | 2025-08-31 09:47:01.527Z | 29.878° NE | 2025-08-31 09:50:01.527Z | 61.369° ENE | 17.141° | 2025-08-31 09:54:01.527Z | 102.509° ESE |
| 10 mins | 2025-08-31 11:31:01.527Z | 342.408° N | 2025-08-31 11:35:01.527Z | 296.454° NW | 43.031° | 2025-08-31 11:41:01.527Z | 179.972° S |
| 6 mins | 2025-08-31 23:09:01.527Z | 115.136° SE | 2025-08-31 23:11:01.527Z | 89.529° E | 19.185° | 2025-08-31 23:15:01.527Z | 44.559° NE |
| 10 mins | 2025-09-01 00:51:01.527Z | 213.675° SW | 2025-09-01 00:55:01.527Z | 274.777° WNW | 38.159° | 2025-09-01 01:01:01.527Z | 1.275° NNE |
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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Authenticating...
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