Complex sentence: Looking Glass (or Operation Looking Glass) is a code name for an airborne command center operated by the United States Navy that provides command and control of U.S. nuclear forces in the event that ground-based command centers are destroyed or rendered inoperable.
Split into simpler sentences: Looking Glass (or Operation Looking Glass) is a code name for an airplane operated by the United States Navy. Its mission is to provide command and control of U.S. nuclear forces in the event that ground-based command centers are destroyed or rendered inoperable.