Abstract: A Common Bus Structure for Avionics and Satellites (CBSAS) (10) as shown in FIG. 1 is comprised of a module lid (14), module floor (38), module stack base (16), module bolts (22) and stackable modules (12). Stackable modules (12) are sub-dividable to create module sealed chamber volumes (45) individually as required, while stackable modules (12) simultaneously create at least one collectively continuous raceway sealed chamber volume (44) perpendicular to individual stackable modules (12) in the vertical direction where no module floor (38) is present, in order to internally electrically interconnect the contents of any stackable module (12) with the contents of any other stackable module (12) via internal connector raceway system (24). Raceway sealed chamber volume (44) therefore collectively and continuously traverses all present stackable modules (12) positioned between module lid (14) and module stack base (16).