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USA 81, 21949

Orbit data source: Space-Track

USA 81, 21949 is a payload satellite owned by NRO (US) in LEO that was launched on Sat, 25 Apr 1992 UTC via a TITAN II SLV 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/21949?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/21949?theme=dark&initialShowStats=false

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ISO8601 Format

Identifier

21949, 1992-023A

Orbit

LEO

Country

Related business

National Reconnaissance Office (US)

Manufacturer

LMSC/MOTO

Mission

Defense Sigint

Bus & Motor

NRO-T2, Unknown motor

Mass

~1,450 kg wet, ~1,200 kg dry

Launch date (UTC)

1992-04-25 (34 years ago)

Launch vehicle

TITAN II SLV

Launch site

Air Force Western Test Range (AFWTR)

Object type

Payload

Rocket body

Debris

Shape & HBR

Cyl + 1 Ant, 5.0 m

Radar Cross Section

1.422 m², Large (>1 m²)

Expand to show TLE details & history
Last TLE update: 5 hours ago

TLE from 5 hours ago

0 USA 81
1 21949U 92023A   26092.34050965  .00000235  00000-0  79454-4 0  9995
2 21949  85.0041 117.7912 0001605  69.1320 291.0045 14.32375900 98176

Epoch: 2026-04-02T08:10Z

TLE epoch observation values (Epoch: 2026-04-02T08:10:20.033Z)

Latitude

0.00003°

Longitude

164.51734°

Altitude

786.414 km

Speed

7.461 km/s

True Right ascension

07h 51m 09s

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

18:49:48

Azimuth

Unknown

Elevation

Unknown

Doppler factor

Unknown

Orbital elements

Apogee altitude

781.95 km

Perigee altitude

779.652 km

Semi-major axis

7,158.938 km

Eccentricity

0.00016

Inclination

85.0041°

RAAN

117.7912°

Arg. of periapsis

69.132°

True anomaly

290.98733°

Mean anomaly

291.0045°

Eccentric anomaly

290.99591°

Mean motion

3.58319 °/min

Orbital period

100.47 mins

BSTAR

0.000079454

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Other satellites on launch #23 in the year 1992 (1992-04-25 UTC)

TITAN 2 R/B, 21950

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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 81 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.
9 mins	2026-04-02 13:46:42.405Z	355.505° N	2026-04-02 13:50:42.405Z	353.192° N	44.038°	2026-04-02 13:55:42.405Z	177.628° S
5 mins	2026-04-03 01:05:42.405Z	107.63° ESE	2026-04-03 01:07:42.405Z	80.282° E	17.187°	2026-04-03 01:10:42.405Z	43.173° NE
8 mins	2026-04-03 02:44:42.405Z	209.849° SW	2026-04-03 02:47:42.405Z	259.589° W	36.48°	2026-04-03 02:52:42.405Z	351.175° N

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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 81, 21949 on other resources

View USA 81, 21949 on NASA - NSSDCA Website

View USA 81, 21949 on Heavens-Above

View USA 81, 21949 on Keep Track

View USA 81, 21949 on Celestrak

View USA 81, 21949 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 81, 21949

Orbit data source: Space-Track

Expand to show TLE details & historyLast TLE update: 5 hours ago

TLE from 5 hours ago

TLE epoch observation values (Epoch: 2026-04-02T08:10:20.033Z)

Visualization orbit readout

Visualization observer readout

Orbital elements

Other satellites on launch #23 in the year 1992 (1992-04-25 UTC)

USA 81 Visibility forecast

Co-orbital & Co-planar RSOs

Check out USA 81, 21949 on other resources

Documentation

Expand to show TLE details & history
Last TLE update: 5 hours ago