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TDRS 5, 21639

Orbit data source: Space-Track

TDRS 5, 21639 is a payload satellite owned by GSFC (US) in GEO that was launched on Fri, 02 Aug 1991 UTC via an SPACE SHUTTLE launch vehicle from the Air Force Eastern Test Range (AFETR). 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 URL

https://www.satcat.com/sats-embedded/21639?theme=dark&initialShowStats=false

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Identifier

21639, 1991-054B

Orbit

GEO

Country

Related business

National Aeronautics and Space Administration (NASA) (US)

Manufacturer

TRW

Mission

Operational Civil Communications

Bus & Motor

TDRS, AOCS

Mass

2,534 kg wet, ~1,700 kg dry

Launch date (UTC)

1991-08-02 (35 years ago)

Launch vehicle

SPACE SHUTTLE

Launch site

Air Force Eastern Test Range (AFETR)

Object type

Payload

Rocket body

Debris

Shape & HBR

Hex Cyl + 2 Pan, 8.9 m

Radar Cross Section

13.873 m², Large (>1 m²)

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Last TLE update: 9 hours ago

TLE from 9 hours ago

0 TDRS 5
1 21639U 91054B   26149.31710573  .00000083  00000-0  00000+0 0  9999
2 21639  14.0737 353.9222 0006161 285.5521 273.9488  1.00267879127521

Epoch: 2026-05-29T07:36Z

TLE epoch observation values (Epoch: 2026-05-29T07:36:37.935Z)

Latitude

-4.65874°

Longitude

-168.18486°

Altitude

35,786.062 km

Speed

3.075 km/s

True Right ascension

12h 51m 17s

True Declination

-4° 39' 15"

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

02:08:23

Azimuth

Unknown

Elevation

Unknown

Doppler factor

Unknown

Orbital elements

Apogee altitude

35,814.647 km

Perigee altitude

35,762.689 km

Semi-major axis

42,166.805 km

Eccentricity

0.00062

Inclination

14.0737°

RAAN

353.9222°

Arg. of periapsis

285.5521°

True anomaly

273.87836°

Mean anomaly

273.9488°

Eccentric anomaly

273.91358°

Mean motion

0.25066 °/min

Orbital period

1,436.2 mins

BSTAR

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Other satellites on launch #54 in the year 1991 (1991-08-02 UTC)

IUS R/B(2), 21641

IUS R/B(1), 21640

IUS DEB, 21642 (Decayed)

STS 43, 21638 (Decayed)

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TDRS 5 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.
817 mins	2026-05-29 17:19:58.844Z	248.56° W	2026-05-30 00:48:58.844Z	262.993° W	20.582°	2026-05-30 06:56:58.844Z	249.842° W

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21639 neighbors

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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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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

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Check out TDRS 5, 21639 on other resources

View TDRS 5, 21639 on NASA - NSSDCA Website

View TDRS 5, 21639 on Heavens-Above

View TDRS 5, 21639 on Keep Track

View TDRS 5, 21639 on Celestrak

View TDRS 5, 21639 on Gunter's Space Page

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

TDRS 5, 21639

Orbit data source: Space-Track

Expand to show TLE details & historyLast TLE update: 9 hours ago

TLE from 9 hours ago

TLE epoch observation values (Epoch: 2026-05-29T07:36:37.935Z)

Visualization orbit readout

Visualization observer readout

Orbital elements

Other satellites on launch #54 in the year 1991 (1991-08-02 UTC)

TDRS 5 Visibility forecast

21639 neighbors

Co-orbital & Co-planar RSOs

Check out TDRS 5, 21639 on other resources

Documentation

Expand to show TLE details & history
Last TLE update: 9 hours ago