Meteosat-10 replacement

According to this page, Meteosat-11 replaced Meteosat-10 at 0° on 20 February 2018.

This is not a real close encounter (the minimum distance between the satellites was about 2000 km), but it is really interesting to see what EUMETSAT did to replace Meteosat-10. Let's see what happened with the help of TLEs, SDP4 propagator and some graphs.

The graph shows the Meteosat-11 longitude and the mean radius vector.

Before February, the satellite longitude was in the range 3.2 to 3.6 degrees west.
Since that location is not stable, Meteosat-11 needed to be reboosted every 87 days for the normal station-keeping.

When EUMETSAT needed to replace the Meteosat-10, they deboosted the Meteosat-11 (\(\Delta R = 35.3\ km\) and \(\Delta V = 1.3\ m/s\)) to increase the orbital speed and hence to start moving it eastward.
When the satellite reached the new intended longitude, they reboosted the satellite (\(\Delta R = 40.3\ km\) and \(\Delta V = 1.5\ m/s\)) to decrease the orbital speed and hence stopping the eastward motion.

EUMETSAT is now doing the normal station-keeping manoeuvres to keep the longitude in the range -0.2° to 0.8°, which is a similar range used for the Meteosat-10, as explained here.
This graph shows the longitude evolution during the replacement.
The green segments represent the deboost and the reboost phases. The dots represent the TLEs.

It is clearly shown the eastward longitude shift during the "low altitude" phase.


The next two graphs show the mean radius vector and the mean orbital speed during the replacement: