Key statistics
Satellite NAVSTAR 51 (USA 166) at a glance.
Uptime
8355
Days in orbit
Revolutions
≈ 2.0
Per day
Orbit
MEO
Medium Earth Orbit
Inclination
54.9
Latest
Satellite identification and parameters
Extended collection of information and parameters for NAVSTAR 51 (USA 166).
Object identification
Identified? True
Debris? False
Object name: NAVSTAR 51 (USA 166)
International designator: 2003-005A
Object number (NORAD): 27663
Object ID (CCSDS): 27663
Country: UNITED STATES OF AMERICA (US)
Current information (Y/N): Y
RCS size: LARGE
Orbital parameters
Period: 717.951 minutes
Inclination: 54.9232 deg
SMA: 26559.703 km
Apoapsis: 20573.29 km
Periapsis: 19789.846 km
RAAN: 222.3526 deg
Eccentricy: 0.01474873
Argument of periapsis: 51.8083 deg
Mean anomaly: 128.0829 deg
Mean motion: 2.00570905 rev/day
Mean motion (dot): 0.00000023 rev/day2
B* drag term: 0.0 1/REarth
Two-line elements (TLE)
Creation date: Dec. 14, 2025, 3:07 a.m.
Reference frame: TEME
Reference center: EARTH
Epoch: Dec. 13, 2025, 9:15 a.m. UTC
TLE line 0: 0 NAVSTAR 51 (USA 166)
TLE line 1: 1 27663U 03005A 25347.38572791 .00000023 00000-0 00000-0 0 9990
TLE line 2: 2 27663 54.9232 222.3526 0147487 51.8083 128.0829 2.00570905167584
Live tracking on map
Real-time ground track for satellite NAVSTAR 51 (USA 166).
In-orbit conjunctions
There are no conjunctions computed for NAVSTAR 51 (USA 166), at the moment. Check back to stay up to date, as we update our databases every day.
Go to all conjunctionsAssociated space launch
USA-166, also known as GPS IIR-8 and GPS SVN-56, is an American navigation satellite which forms part of the Global Positioning System. It was the eighth Block IIR GPS satellite to be launched, out of thirteen in the original configuration, and twenty one overall.
NAVSTAR 51 (USA 166) was lifted into orbit during the mission ‘Delta II | GPS IIR-8’, on board a Delta II space rocket.
The launch took place on Jan. 29, 2003, 6:06 p.m. from Space Launch Complex 17B.
For more information about the launch, click the button.
Delta II | GPS IIR-8
Agency: N/A
Status: Launch Successful
Launch date: Jan. 29, 2003, 6:06 p.m. UTC
Rocket: Delta II
Launch pad: Space Launch Complex 17B
Location: Cape Canaveral SFS, FL, USA
...
Latest news about this satellite
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