Defensive shields are physical protective barriers that enclose around the viewing screen and possibly the exterior of Core command on a battlestar.
Commander Adama orders activation of these shields as they fight off the first waves of a Cylon Raider attack on Galactica and her sister battlestars in the opening salvos of the ill-fated Battle of Cimtar (Saga of a Star World). Adama's commands to activate and deactivate the shield are "Positive shields" and "Negative shields", respectively.
Notes
- The physical properties, energy properties, or overall protection given by these shields are never explained in the Original Series.
- In comparison, Galactica's counterpart in the Re-imagined Series uses heavy armoring and ribbing through out its superstructure, enabling it to withstand a direct nuclear missile strike to its hull.