Permanent Bases

Unlike ships, which are built in one place and immediately go into service, permanent bases begin their lives as Mobile Bases. They are ferried by tug to their final location, and the positional stabilizers are activated. Over the years, they may be upgraded to Base Stations, Battle Stations, and eventually Starbases.

Each upgrade from a Mobile Base to a Y-era base (and on) requires at least one Fleet Repair Dock (or an equivalent number of Repair boxes) or a Tug and costs the EPV of the YBS. Upgrading from a YBS to a YDK requires an FRD or a Tug and costs twice the EPV difference between the YBS and the YDK.

Each upgrade from a Mobile Base to a Middle Years base (and on) requires a Tug and twice the difference in EPV.

Bases at a major planet may be upgraded without the need for a Tug or FRD. The planet is considered to have the necessary facilities for such an activity.

Unit	EP Cost	Upgrade Time
Mobile Base Construction	MB EPV	2 Turns
Mobile Base to Early Base Station	YBS EPV	1 Turn
Early Base Station to Spacedock	2xEPV Difference	2 Turns
Mobile Base to Base Station	2xEPV Difference	1 Turn
Base Station to Battle Station	2xEPV Difference	1 Turn
Battle Station to Starbase	500EP	3 Turns
Middle Years Base to X-Base	2xEPV Difference	1 Turn

While the upgrade is in progress, the section undergoing upgrade at the time of an attack will be non-functional.