Showing default

USA 77, 21809

Orbit data source: Space-Track

USA 77, 21809 is an American payload satellite in LEO that was launched on Fri, 08 Nov 1991 UTC via a TITAN 403A 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/21809?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/21809?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

21809, 1991-076E

Orbit

LEO

Last TLE update

6 hours ago

Origin

National Reconnaissance Office (US)

Manufacturer

NRL

Mission

Defense Sigint

Bus & Motor

NOSS B SSU, Unknown motor

Mass

~400 kg wet, ~400 kg dry

Launch date (UTC)

1991-11-08 (34 years ago)

Launch vehicle

TITAN 403A

Launch site

Air Force Western Test Range (AFWTR)

Object type

Payload

Rocket body

Debris

Shape & HBR

Cyl, 1 m

Radar Cross Section

1.178 m², Large (>1 m²)

Expand to show TLE details & history

TLE from 6 hours ago

0 USA 77
1 21809U 91076E   25185.62750188  .00003575  00000-0  31726-3 0  9993
2 21809  63.3016   3.5672 0900676  68.1039 301.3235 13.53479587 57178

Epoch: 2025-07-04T15:03Z

TLE epoch observation values (Epoch: 2025-07-04T15:03:36.162Z)

Latitude

-0.00005°

Longitude

-145.21068°

Altitude

760.076 km

Speed

7.625 km/s

True Right ascension

00h 14m 16s

True Declination

0° 00' 00"

Sunlit

Object was in daylight at epoch

Visualization orbit readout

Latitude

41.90954°

Longitude

-119.15364°

Altitude

427.928 km

Speed

7.981 km/s

Apparent Right ascension

23h 16m 20s

Apparent Declination

3° 28' 03"

Sunlit

Object is in daylight

Visualization observer readout

Local Sidereal Time

08:27:10

Azimuth

307.752° NW

Elevation

-31.835°

Doppler factor

Orbital elements

Apogee altitude

1,728.089 km

Perigee altitude

388.524 km

Semi-major axis

7,436.443 km

Eccentricity

0.09007

Inclination

63.3016°

RAAN

3.5672°

Arg. of periapsis

68.1039°

True anomaly

Unknown

Mean anomaly

301.3235°

Eccentric anomaly

Unknown

Mean motion

3.38451 °/min

Orbital period

106.37 mins

BSTAR

0.00031726

Loading maneuver chart data...

Loading SW <> Apogee altitude chart data...

Loading historical data...

Other satellites on launch #76 in the year 1991 (1991-11-08 UTC)

USA 77 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.
9 mins	2025-07-04 22:40:13.363Z	323.658° NNW	2025-07-04 22:43:13.363Z	286.111° WNW	44.615°	2025-07-04 22:49:13.363Z	150.043° SSE
4 mins	2025-07-05 14:17:13.363Z	246.787° WSW	2025-07-05 14:19:13.363Z	299.033° NW	30.055°	2025-07-05 14:21:13.363Z	5.727° NNE

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 ascending order

Check out USA 77, 21809 on other resources

View USA 77, 21809 on NASA - NSSDCA Website

View USA 77, 21809 on Heavens-Above

View USA 77, 21809 on Keep Track

View USA 77, 21809 on Celestrak

View USA 77, 21809 on Gunter's Space Page

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