Key statistics
Satellite GP-B at a glance.
Uptime
7812
Days in orbit
Revolutions
≈ 14.8
Per day
Orbit
LEO
Low Earth Orbit
Inclination
89.8
Latest
Satellite identification and parameters
Extended collection of information and parameters for GP-B.
Object identification
Identified? True
Debris? False
Object name: GP-B
International designator: 2004-014A
Object number (NORAD): 28230
Object ID (CCSDS): 28230
Country: UNITED STATES OF AMERICA (US)
Current information (Y/N): Y
RCS size: LARGE
Orbital parameters
Period: 97.126 minutes
Inclination: 89.8368 deg
SMA: 6999.212 km
Apoapsis: 622.56 km
Periapsis: 619.594 km
RAAN: 55.6849 deg
Eccentricy: 0.00021185
Argument of periapsis: 104.5249 deg
Mean anomaly: 255.6211 deg
Mean motion: 14.82617179 rev/day
Mean motion (dot): 0.00001191 rev/day2
B* drag term: 0.00014603233 1/REarth
Two-line elements (TLE)
Creation date: Sept. 8, 2025, 6:18 p.m.
Reference frame: TEME
Reference center: EARTH
Epoch: Sept. 8, 2025, 12:27 p.m. UTC
TLE line 0: 0 GP-B
TLE line 1: 1 28230U 04014A 25251.51913297 .00001191 00000-0 14603-3 0 9995
TLE line 2: 2 28230 89.8368 55.6849 0002119 104.5249 255.6211 14.82617179610605
Live tracking on map
Real-time ground track for satellite GP-B.
In-orbit conjunctions
A list of the most updated potential collisions computed for object GP-B.
Associated space launch
Gravity Probe B (GP-B) was a satellite-based experiment to test two unverified predictions of general relativity: the geodetic effect and frame-dragging. This was to be accomplished by measuring, very precisely, tiny changes in the direction of spin of four gyroscopes contained in an Earth-orbiting satellite at 650 km (400 mi) altitude, crossing directly over the poles.
GP-B was lifted into orbit during the mission ‘Delta II | Gravity Probe B’, on board a Delta II space rocket.
The launch took place on April 20, 2004, 4:57 p.m. from Space Launch Complex 2W.
For more information about the launch, click the button.
Delta II | Gravity Probe B
Agency: N/A
Status: Launch Successful
Launch date: April 20, 2004, 4:57 p.m. UTC
Rocket: Delta II
Launch pad: Space Launch Complex 2W
Location: Vandenberg SFB, CA, USA
...
Latest news about this satellite
There are no fresh news available about this satellite. Check back as we update our databases every day.
Newsletter sign-up
Weekly statistics, charts and insights to help you stay on top of the space industry.
