Showing default

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.

Loading next visibility...

Iframe embed code

<iframe src="https://www.satcat.com/sats-embedded/870?theme=dark&initialShowStats=false" width="600" height="400" frameborder="0" title="Kayhan Space Satcat Satellite Viewer"></iframe>

Iframe URL

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

Optional Secondary NORAD IDs

Max 10 NORAD IDs; Separated by commas

Initial load time (optional)

ISO8601 Format

TLE date request (optional)

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

DCONE + 6 ANT, 18.5 m

Radar Cross Section

Medium (>0.1 m² and <1 m²)

Expand to show TLE details & history
Last TLE update: 22 hours ago

TLE from 22 hours ago

0 EXPLORER 20
1 00870U 64051A   26207.56408879  .00000123  00000-0  87317-4 0  9991
2 00870  79.8954 235.8862 0097090 179.5693 180.5566 13.91798067138912

Epoch: 2026-07-26T13:32Z

TLE epoch observation values (Epoch: 2026-07-26T13:32:17.271Z)

Latitude

0.00005°

Longitude

88.55404°

Altitude

996.055 km

Speed

7.318 km/s

True Right ascension

15h 43m 32s

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

01:17:34

Azimuth

Unknown

Elevation

Unknown

Doppler factor

Unknown

Orbital elements

Apogee altitude

990.457 km

Perigee altitude

848.75 km

Semi-major axis

7,297.74 km

Eccentricity

0.00971

Inclination

79.8954°

RAAN

235.8862°

Arg. of periapsis

179.5693°

True anomaly

180.54592°

Mean anomaly

180.5566°

Eccentric anomaly

180.55125°

Mean motion

3.48145 °/min

Orbital period

103.41 mins

BSTAR

0.000087317

Loading maneuver chart data...

Computing Atmospheric mass density...

Loading historical data...

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

SCOUT X-4 DEB, 873 (Decayed)

SCOUT X-4 DEB, 875 (Decayed)

SCOUT X-4 DEB, 40592 (Decayed)

SCOUT X-4 R/B, 871

SCOUT X-4 DEB, 874 (Decayed)

Did you know?

You can import UDL-sourced sensor .json files into the Sandbox to generate a visibility chart that accounts for multi-vendor sensor geometry.

Click here to try in Sandbox

EXPLORER 20 Visibility forecast

Loading observer location...
Set 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.
8 mins	2026-07-27 12:33:19.099Z	19.275° NNE	2026-07-27 12:37:19.099Z	69.932° E	22.578°	2026-07-27 12:41:19.099Z	119.015° SE
8 mins	2026-07-27 14:18:19.099Z	326.875° NNW	2026-07-27 14:22:19.099Z	257.286° W	33.549°	2026-07-27 14:26:19.099Z	201.197° SSW
9 mins	2026-07-28 01:53:19.099Z	149.477° SSE	2026-07-28 01:57:19.099Z	100.552° ESE	29.783°	2026-07-28 02:02:19.099Z	33.555° NE
9 mins	2026-07-28 03:38:19.099Z	234.198° WSW	2026-07-28 03:42:19.099Z	288.863° WNW	29.316°	2026-07-28 03:47:19.099Z	350.354° N

Items per page:

1–4 of 4 items

of 1 page

Co-orbital & Co-planar RSOs

Thresholds — Semi-major Axis: ±100 km, RAAN: ±3°, Inclination: ±5°
TCA is derived from TLE conjunctions

Please sign-in to view Co-orbital & Co-planar RSOs.

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

CAUTION: Conjunctions in this section are generated from low-fidelity TLE screenings

Authenticating...

Click to sort rows by Secondary header in ascending order	Click to sort rows by Secondary name header in ascending order	Click to sort rows by Country header in ascending order	Click to sort rows by Owner header in ascending order	Click to sort rows by Obj. Type header in ascending order	Click to sort rows by Miss dist. header in ascending order	Click to sort rows by Rel. speed header in ascending order	Click to sort rows by Apr. angle header in ascending order	Click to sort rows by TCA header in descending order

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: 22 hours ago

TLE from 22 hours ago

TLE epoch observation values (Epoch: 2026-07-26T13:32:17.271Z)

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: 22 hours ago