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.
Focus sentinelFocus sentinel
Request partner network tasking
Focus sentinelFocus sentinel
Embed this page
Focus sentinelFocus sentinel
731 intel report (Beta)
Focus sentinelFocus sentinel
Edit Public Description
Focus sentinelFocus sentinel
Edit Sat Name
Focus sentinelFocus sentinel
Create New Watchlist
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: 1 day ago
TLE from 1 day ago
0 GREB
1 00731U 64001E 26163.05451270 -.00000008 00000-0 33052-4 0 9990
2 00731 69.9065 278.1009 0012503 24.8657 335.3048 13.96309367176869Epoch: 2026-06-12T01:18Z
TLE epoch observation values (Epoch: 2026-06-12T01:18:29.897Z)
Latitude
-0.00002°
Longitude
-1.91314°
Altitude
900.635 km
Speed
7.406 km/s
True Right ascension
18h 32m 24s
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
19:57:16
Azimuth
Unknown
Elevation
Unknown
Doppler factor
Unknown
Orbital elements
Apogee altitude
913.761 km
Perigee altitude
895.55 km
Semi-major axis
7,282.793 km
Eccentricity
0.00125
Inclination
69.9065°
RAAN
278.1009°
Arg. of periapsis
24.8657°
True anomaly
335.24486°
Mean anomaly
335.3048°
Eccentric anomaly
335.27484°
Mean motion
3.49218 °/min
Orbital period
103.09 mins
BSTAR
0.000033052
Loading maneuver chart data...
Computing Atmospheric mass density...
Loading historical data...
Loading historical data...
Loading historical data...
Loading historical data...
Loading historical data...
Loading historical data...
Loading historical data...
Other satellites on launch #1 in the year 1964 (1964-01-11 UTC)
Did you know?
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
Loading observer location...
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 | 2026-06-13 10:07:54.088Z | 248.468° W | 2026-06-13 10:12:54.088Z | 311.455° NW | 25.822° | 2026-06-13 10:16:54.088Z | 0.368° NNE |
| 8 mins | 2026-06-13 17:24:54.088Z | 8.061° NNE | 2026-06-13 17:27:54.088Z | 47.793° ENE | 24.886° | 2026-06-13 17:32:54.088Z | 109.308° ESE |
| 9 mins | 2026-06-13 19:09:54.088Z | 318.06° NNW | 2026-06-13 19:13:54.088Z | 257.328° W | 36.291° | 2026-06-13 19:18:54.088Z | 182.961° SSW |
| 10 mins | 2026-06-14 08:26:54.088Z | 185.338° SSW | 2026-06-14 08:30:54.088Z | 129.275° SE | 40.689° | 2026-06-14 08:36:54.088Z | 32.1° NE |
Co-orbital & Co-planar RSOs
Thresholds — Semi-major Axis: ±100 km, RAAN: ±3°, Inclination: ±5°
TCA is derived from TLE conjunctions
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
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 descending order |
|---|