Traveller: Naval Adventure 2 - Showing the Sunburst - Rules of Play says:

Taking command of a warship assigned to the troubled Jewell-Vilis naval station, the Travellers are sent on what looks like a simple flag-showing mission. All they have to do is visit a few worlds, remind friend and foe alike that the navy is around, and give assistance to Imperial diplomats operating in the region. There is, however, a sealed section in their orders – to be opened after their ship leaves port. Shakedown Cruise is a complete naval mission for Traveller. A copy of the Element Class Cruiser: Shipbuilder’s Blueprints box set is required.