This event repeats every week on Sunday forever
Welcome to "Good Morning PvP" event. It's all about the Unranked PvP games we play every Sunday starting at 9 PM. How it works is that 1 week it will be on the Republic side and then Imperial side the next. The schedule will be the same.
To know which side it's happening on, in case you forget or miss a few, keep watch on the PvP subforum: SWTOR > Deployment Hangar > PVP DEPARTMENT EVENT SCHEDULING.