Help: BUILD fortifications on a captured planet

Syntax:  BUild [Absolute|Relative] <vpos> <hpos>

A  fortified  planet  hits  harder  and  is  more  resistant  to
destruction  by the enemy.  A planet can normally be built up to
4 times.  As  your  team's  starbases  are  destroyed  by  enemy
action,  a  fifth  build will complete the construction of a new
starbase on the planet.  Only 10 starbases can be functional  at
any one time.

Examples:

BU 32 12        Build the planet at sector 32-12.
BU A 32 12      Equivalent to "BU 32 12"
BU R 1 1        Build the planet at sector 32-12, if your
                present location is 31-11.