On the ground immediately north of the firehouse is an octagonal foundation that is the remains of one of four celestial navigation buildings. These silo-like buildings, used to train aircrews, were some of the tallest structures on the base. Inside each silo was a simulated cockpit, capable of holding four people (pilot, co-pilot, navigator, and radio operator or instructor), elevated on a movable armature, under a dome with lights set in a pattern resembling stars. Landscapes were projected below the cockpit, so that bombing runs could by simulated under nighttime conditions, navigating by stars. This remarkable system was designed by the Link Company. Several bases around the USA had these training silos in place during the war, none of which seem to have survived.