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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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https://www.satcat.com/sats-embedded/870?theme=dark&initialShowStats=false

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ISO8601 Format

Identifier

870, 1964-051A

Orbit

LEO

Country

Related business

National Aeronautics and Space Administration (NASA) (US)

Manufacturer

Cutler-Hammer/AIL

Mission

Spacecraft

Bus & Motor

S-48, Unknown motor

Mass

44 kg wet, 44 kg dry

Launch date (UTC)

1964-08-25 (62 years ago)

Launch vehicle

SCOUT X-4

Launch site

Air Force Western Test Range (AFWTR)

Object type

Payload

Rocket body

Debris

Shape & HBR

Unknown

Radar Cross Section

Medium (>0.1 m² and <1 m²)

Expand to show TLE details & history
Last TLE update: 13 hours ago

TLE from 13 hours ago

0 EXPLORER 20
1 00870U 64051A   26104.11789829  .00000110  00000-0  76617-4 0  9992
2 00870  79.9005 348.4727 0097556  91.8751 269.3581 13.91778381124521

Epoch: 2026-04-14T02:49Z

TLE epoch observation values (Epoch: 2026-04-14T02:49:46.412Z)

Latitude

-0.00005°

Longitude

103.73056°

Altitude

926.727 km

Speed

7.388 km/s

True Right ascension

23h 13m 53s

True Declination

0° 00' 00"

Sunlit

Object was in daylight at epoch

Visualization orbit readout

Latitude

Unknown

Longitude

Unknown

Altitude

Unknown

Speed

Unknown

Apparent Right ascension

Unknown

Apparent Declination

Unknown

Sunlit

N/A

Visualization observer readout

Local Sidereal Time

22:23:02

Azimuth

Unknown

Elevation

Unknown

Doppler factor

Unknown

Orbital elements

Apogee altitude

990.867 km

Perigee altitude

848.478 km

Semi-major axis

7,297.809 km

Eccentricity

0.00976

Inclination

79.9005°

RAAN

348.4727°

Arg. of periapsis

91.8751°

True anomaly

268.24048°

Mean anomaly

269.3581°

Eccentric anomaly

268.79927°

Mean motion

3.4814 °/min

Orbital period

103.41 mins

BSTAR

0.000076617

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Other satellites on launch #51 in the year 1964 (1964-08-25 UTC)

SCOUT X-4 DEB, 875 (Decayed)

SCOUT X-4 DEB, 873 (Decayed)

SCOUT X-4 R/B, 871

SCOUT X-4 DEB, 874 (Decayed)

SCOUT X-4 DEB, 40592 (Decayed)

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EXPLORER 20 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.
10 mins	2026-04-14 16:44:10.394Z	170.999° S	2026-04-14 16:49:10.394Z	102.114° ESE	39.211°	2026-04-14 16:54:10.394Z	22.082° NNE
6 mins	2026-04-14 18:32:10.394Z	266.094° W	2026-04-14 18:34:10.394Z	291.822° WNW	18.452°	2026-04-14 18:38:10.394Z	337.947° N
9 mins	2026-04-15 03:34:10.394Z	2.467° NNE	2026-04-15 03:38:10.394Z	73.521° E	39.796°	2026-04-15 03:43:10.394Z	152.441° SSE
5 mins	2026-04-15 05:20:10.394Z	298.958° NW	2026-04-15 05:22:10.394Z	274.486° WNW	17.09°	2026-04-15 05:25:10.394Z	239.231° WSW

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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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Check out EXPLORER 20, 870 on other resources

View EXPLORER 20, 870 on NASA - NSSDCA Website

View EXPLORER 20, 870 on Heavens-Above

View EXPLORER 20, 870 on Keep Track

View EXPLORER 20, 870 on Celestrak

View EXPLORER 20, 870 on Gunter's Space Page

Satcat and Kayhan Space are not affiliated with NASA, Celestrak, Heavens-Above, Keep Track, or Gunter's Space Page.

EXPLORER 20, 870

Orbit data source: Space-Track

Expand to show TLE details & historyLast TLE update: 13 hours ago

TLE from 13 hours ago

TLE epoch observation values (Epoch: 2026-04-14T02:49:46.412Z)

Visualization orbit readout

Visualization observer readout

Orbital elements

Other satellites on launch #51 in the year 1964 (1964-08-25 UTC)

EXPLORER 20 Visibility forecast

Co-orbital & Co-planar RSOs

Check out EXPLORER 20, 870 on other resources

Documentation

Expand to show TLE details & history
Last TLE update: 13 hours ago