This is an Invitation to Register Interest for the Design Services package of works (Defence Contract DSC-1 2021) under project ESTS4000PH6 Facilities to Support the Hobart Class Destroyer Combat System Enhancement Capability Project (the Project). SEA4000PH6 aims to deliver an Aegis Baseline 9 and Australian Interface combat system enhancement to the Hobart Class Guided Missile Destroyers. The facilities component of the Project focuses on delivering suitable land-based facilities to support SEA4000-6 prior to Q2 2027 in order to support Initial Operating Capability (IOC).