GALILEO-FM2
Country: European Space Agency
Live Position
Ground Track · Last 90 Minutes
Upcoming Passes · Over Your Location
About This Satellite
Galileo FM2, also identified as GSAT0102, was one of the first two Galileo In-Orbit Validation spacecraft launched on October 21, 2011. It helped establish the navigation constellation after the earlier GIOVE technology experiments. Its catalog identity should not be confused with a later flight merely carrying the number two in a different naming scheme.
A working radio signal still needed detailed testing
ESA's Redu centre checked the first pair's navigation payloads across three radio bands. A 20-metre antenna measured signal characteristics from medium Earth orbit, while a smaller antenna supported telemetry and command tests. Detecting a transmission was only the beginning: the campaign examined whether the payload met its intended performance.
Navigation validation involved more than the spacecraft bus
The Redu campaign was part of validating Galileo as a system. Communications used to monitor and command a satellite serve a different purpose from the navigation signals measured by user receivers. A successful spacecraft-control link alone does not establish the quality of a positioning solution.
Mission reference: ESA: first Galileo pair and the Redu in-orbit navigation-payload test campaign. Editorial review: .
FM2 does not carry the distress-signal repeater fitted to later vehicles
The European GNSS Service Centre explicitly excludes GSAT0101 and GSAT0102 from the Galileo satellites equipped with the SARR search-and-rescue repeater. GSAT0102 can nevertheless appear in the Return Link Service table. These are different functions: absence of the forward-link repeater must not be turned into a claim that the spacecraft has no role in any return-link service. Nor should a generic Galileo payload diagram be assumed to describe FM2 exactly.
Reference: European GNSS Service Centre: GSAT0102 SARR exception and separate forward/return-link status.
E12 identifies a ranging code, not orbital longitude
The official constellation table associates GSAT0102 with E12 and explains that the SV ID denotes the satellite ranging code. Its service status and active Notice Advisory to Galileo Users entries are separate fields. Consult that table for current usability; the enduring spacecraft name and a fresh orbital element set do not replace a service-health notice. This profile deliberately keeps mission history separate from changing operational status.
Reference: European GNSS Service Centre: GSAT0102 identity, E12 and status-field definitions.
Reading this orbital snapshot
Based on TLE epoch: 2026-08-26. Estimated altitude ranges from 23,218 km at perigee to 23,226 km at apogee, a difference of 9 km. The orbital period is about 844.7 minutes. Eccentricity 0.00015 indicates a nearly circular path. In a two-body approximation, perigee speed is 1.00 times apogee speed. These are mean-element estimates, not instantaneous measurements. Distance per orbit uses an ellipse approximation.
Saved build snapshot. If a valid TLE is retrieved, this explanation and the orbit panel update together. Otherwise this dated snapshot is retained.
Ground track is not sensor coverage
An inclination of 56.97 degrees implies approximate geocentric ground-track limits of 57.0 degrees north and south. This is a prograde orbit, moving in the same general direction as Earth rotation. The plotted line marks the point beneath the object. It does not represent camera coverage, radio reception, or a guaranteed visible pass.
Accuracy and missing information
The introductory record describes the build snapshot. The orbital snapshot explanation and orbit panel share any successfully retrieved TLE; check the displayed epoch. Reentered objects retain historical data only. Mission history is not rewritten by TLE updates. TLE/SGP4 positions are predictions and can change after maneuvers or updated observations. The 14-day stale-data cutoff is a display safeguard, not an accuracy guarantee. Local passes are geometric predictions, not a visibility forecast. No verified operator or mission status means unknown, not active. Do not use this catalog for collision avoidance or operational flight decisions.
Catalog sources: CelesTrak SATCAT: NORAD 37847 · GCAT: S37847 (source update 2026 Sep 4 2345:57). Supplementary metadata: SatNOGS DB, retrieved 2026-09-05T12:57:25.375Z. Page assembled 2026-09-15. GCAT phase codes describe trajectory phases, not mission health.
Learn more: TLE data · Perigee and apogee · Ground tracks · JOT (Jewawud Live Orbital Map)