FY-1C did not maneuver
This shows the orbital period versus time for FY-1C.
At the highest magnification we see a periodic change in the
orbital period which is probably due to the definition of "mean elements"
in the NORAD orbital model; it does not reflect meaningful changes
in the spacecraft's orbit. At the more global level we see
a significant change in orbital period in 2002, followed by
a steady slow decline. There is no evidence for active orbital
maintenance since 2002. The 2002 change could be a maneuver (perhaps to clear
the original orbit to avoid collisions with FY-1D) or some kind
of orbital resonance.
The spike at the end of the data in 2007 is due to two post-intercept
elsets which presumably refer to debris objects and should not have
been assigned to FY-1C.