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USA 18, 16631

Orbit data source: Space-Track

USA 18, 16631 is an American payload satellite in LEO that was launched on Sun, 09 Feb 1986 UTC via an ATLAS H 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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<iframe src="https://www.satcat.com/sats-embedded/16631?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/16631?theme=dark&initialShowStats=false

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ISO8601 Format

Identifier

16631, 1986-014H

Orbit

LEO

Country

Related business

National Reconnaissance Office (US)

Manufacturer

Martin Marietta

Mission

Spacecraft

Bus & Motor

NOSS SSU, Unknown motor

Mass

200 kg wet, 200 kg dry

Launch date (UTC)

1986-02-09 (40 years ago)

Launch vehicle

ATLAS H

Launch site

Air Force Western Test Range (AFWTR)

Object type

Payload

Rocket body

Debris

Shape & HBR

Unknown

Radar Cross Section

Large (>1 m²)

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Last TLE update: 3 days ago

TLE from 3 days ago

0 USA 18
1 16631U 86014H   26170.97298310  .00010173  00000-0  62481-3 0  9997
2 16631  63.2954  20.8864 0753796 112.5673 255.6893 13.92293251344745

Epoch: 2026-06-19T23:21Z

TLE epoch observation values (Epoch: 2026-06-19T23:21:05.739Z)

Latitude

-0.00005°

Longitude

122.41818°

Altitude

1,096.187 km

Speed

7.217 km/s

True Right ascension

01h 23m 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

23:08:00

Azimuth

Unknown

Elevation

Unknown

Doppler factor

Unknown

Orbital elements

Apogee altitude

1,469.497 km

Perigee altitude

369.324 km

Semi-major axis

7,297.548 km

Eccentricity

0.07538

Inclination

63.2954°

RAAN

20.8864°

Arg. of periapsis

112.5673°

True anomaly

247.53764°

Mean anomaly

255.6893°

Eccentric anomaly

251.59137°

Mean motion

3.48159 °/min

Orbital period

103.4 mins

BSTAR

0.00062481

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Other satellites on launch #14 in the year 1986 (1986-02-09 UTC)

USA 15 DEB, 44435 (Decayed)

USA 15 DEB, 16630 (Decayed)

USA 15 DEB, 16622

USA 15 DEB, 16623 (Decayed)

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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.

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USA 18 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.
8 mins	2026-06-22 15:15:43.192Z	206.284° SW	2026-06-22 15:20:43.192Z	100.163° ESE	43.839°	2026-06-22 15:23:43.192Z	39.52° NE
5 mins	2026-06-23 00:18:43.192Z	310.629° NW	2026-06-23 00:20:43.192Z	224.53° SW	39.134°	2026-06-23 00:23:43.192Z	160.117° S

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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 USA 18, 16631 on other resources

View USA 18, 16631 on NASA - NSSDCA Website

View USA 18, 16631 on Heavens-Above

View USA 18, 16631 on Keep Track

View USA 18, 16631 on Celestrak

View USA 18, 16631 on Gunter's Space Page

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

USA 18, 16631

Orbit data source: Space-Track

Expand to show TLE details & historyLast TLE update: 3 days ago

TLE from 3 days ago

TLE epoch observation values (Epoch: 2026-06-19T23:21:05.739Z)

Visualization orbit readout

Visualization observer readout

Orbital elements

Other satellites on launch #14 in the year 1986 (1986-02-09 UTC)

USA 18 Visibility forecast

Co-orbital & Co-planar RSOs

Check out USA 18, 16631 on other resources

Documentation

Expand to show TLE details & history
Last TLE update: 3 days ago