Key statistics
Satellite REX at a glance.
Uptime
12485
Days in orbit
Revolutions
≈ 14.2
Per day
Orbit
LEO
Low Earth Orbit
Inclination
89.5
Latest
Satellite identification and parameters
Extended collection of information and parameters for REX.
Object identification
Identified? True
Debris? False
Object name: REX
International designator: 1991-045A
Object number (NORAD): 21527
Object ID (CCSDS): 21527
Country: UNITED STATES OF AMERICA (US)
Current information (Y/N): Y
RCS size: MEDIUM
Orbital parameters
Period: 101.159 minutes
Inclination: 89.5229 deg
SMA: 7191.696 km
Apoapsis: 862.165 km
Periapsis: 764.956 km
RAAN: 275.6769 deg
Eccentricy: 0.00675837
Argument of periapsis: 202.9105 deg
Mean anomaly: 156.907 deg
Mean motion: 14.23494584 rev/day
Mean motion (dot): 0.00000185 rev/day2
B* drag term: 0.000073942344 1/REarth
Two-line elements (TLE)
Creation date: Sept. 3, 2025, 2:21 a.m.
Reference frame: TEME
Reference center: EARTH
Epoch: Sept. 2, 2025, 7:18 p.m. UTC
TLE line 0: 0 REX
TLE line 1: 1 21527U 91045A 25245.80431269 .00000185 00000-0 73942-4 0 9990
TLE line 2: 2 21527 89.5229 275.6769 0067584 202.9105 156.9070 14.23494584774218
Live tracking on map
Real-time ground track for satellite REX.
In-orbit conjunctions
A list of the most updated potential collisions computed for object REX.
Associated space launch
REX (Radiation Experiment) or ISES (Integrated Space Experiment System) was an Air Force Rome Laboratory ionospheric research satellite which tested the effects of the atmosphere on radio transmissions, and employed GPS for on-board navigation and attitude control.
REX was lifted into orbit during the mission ‘Scout G-1 | REX’, on board a Scout G-1 space rocket.
The launch took place on June 29, 1991, 2 p.m. from Space Launch Complex 5.
For more information about the launch, click the button.
Scout G-1 | REX
Agency: N/A
Status: Launch Successful
Launch date: June 29, 1991, 2 p.m. UTC
Rocket: Scout G-1
Launch pad: Space Launch Complex 5
Location: Vandenberg SFB, CA, USA
...
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