The ultimate treatment of the visitor center that is recommended in this HSR can be described as a rehabilitation project that includes four primary components: 1. preservation and repair of the building's existing historically significant features and material, especially on the exterior and in the Lobby, Museum, and Flight Room, which are the building's principal character- defining spaces; 2. rehabilitation of the building's mechanical and electrical systems to comply with modern building, life safety, and accessibility codes, and to meet current and future programmatic demands; 3. design and construction of a new addition that will add a greatly expanded museum component to the site and accommodate new offices and other service areas; and 4. restoration of the building's most- significant features that have been lost to unsympathetic modern alterations.