GREB, 731
Orbit data source: Space-Track
GREB, 731 is an American payload satellite in LEO that was launched on Sat, 11 Jan 1964 UTC via a THOR SLV-2A AGENA D 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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731 intel report (Beta)
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Identifier
Orbit
Country
USRelated business
Manufacturer
NRL
Mission
Spacecraft
Bus & Motor
NRL 20", Unknown motor
Mass
29 kg wet, 29 kg dry
Launch date (UTC)
Launch vehicle
Launch site
Object type
Shape & HBR
Unknown
Radar Cross Section
Medium (>0.1 m² and <1 m²)
Expand to show TLE details & historyLast TLE update: 16 hours ago
TLE from 16 hours ago
0 GREB
1 731U 64001E 26121.43410198 .00000040 00000-0 67893-4 0 9995
2 731 69.9081 7.5254 0011119 88.4879 271.7500 13.96303278171054Epoch: 2026-05-01T10:25Z
TLE epoch observation values (Epoch: 2026-05-01T10:25:06.411Z)
Latitude
0.00002°
Longitude
-8.11772°
Altitude
908.692 km
Speed
7.398 km/s
True Right ascension
00h 30m 06s
True Declination
0° 00' 00"
Sunlit
Visualization orbit readout
Latitude
Unknown
Longitude
Unknown
Altitude
Unknown
Speed
Unknown
Apparent Right ascension
Unknown
Apparent Declination
Unknown
Sunlit
Visualization observer readout
Local Sidereal Time
09:49:32
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
912.774 km
Perigee altitude
896.579 km
Semi-major axis
7,282.814 km
Eccentricity
0.00111
Inclination
69.9081°
RAAN
7.5254°
Arg. of periapsis
88.4879°
True anomaly
271.62264°
Mean anomaly
271.75°
Eccentric anomaly
271.68632°
Mean motion
3.49216 °/min
Orbital period
103.09 mins
BSTAR
0.000067893
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Other satellites on launch #1 in the year 1964 (1964-01-11 UTC)
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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.GREB 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. |
|---|---|---|---|---|---|---|---|
| 10 mins | 2026-05-02 02:25:57.936Z | 354.705° N | 2026-05-02 02:30:57.936Z | 55.49° ENE | 27.494° | 2026-05-02 02:35:57.936Z | 116.057° SE |
| 9 mins | 2026-05-02 04:12:57.936Z | 311.573° NW | 2026-05-02 04:16:57.936Z | 244.966° WSW | 32.74° | 2026-05-02 04:21:57.936Z | 186.234° SSW |
| 9 mins | 2026-05-02 17:29:57.936Z | 190.828° SSW | 2026-05-02 17:33:57.936Z | 107.696° ESE | 43.38° | 2026-05-02 17:38:57.936Z | 30.082° NE |
| 7 mins | 2026-05-02 19:16:57.936Z | 273.465° WNW | 2026-05-02 19:19:57.936Z | 308.533° NW | 18.681° | 2026-05-02 19:23:57.936Z | 353.519° N |
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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