Beneath the Mobile Launcher Platform (MLP) looking up at the Solid Rocket Motor's (SRM's) Exit Cone, which sits below the Solid Rocket Booster (SRB) Aft Skirt. The Aft Skirt sits atop four Hold Down Posts (HDPs), which are welded to the sides of the MLP.

The orange cap keeps critters and such from nesting and other contaminates from penetrating inside the motor before launch.