The Victorian era was one of discovery and exploration. To do this, brave adventurers would set out on missions, most of which they wouldn't return from, the newest dev diary explains.
In Victoria 3, you will be able to make a Decision to go on an Expedition if you fulfill the prerequisites for it, which is having an interest in the region and, sometimes, some special technology.
For instance, developers give us an example, exploring the African rivers without protection against malaria may not be the greatest idea. Apart from that, any country can decide to embark on this adventurous enterprise.
Most of these Decisions will aad Journal Entries, allowing players to track the progress of the missions themselves. Once you've made the Decision to start an expedition, you will be asked to denote a budget and choose the expedition leader. Expedition leaders can make or break the expeditions, as corrupt ones will divert the budget to their own ends, while incompetent ones will have it end in the worst way for your country possible.
To give players more interaction with expeditions, each in-game month you will be given an update and choices on how the expedition should progress. However, should all be in good order, instead of choosing options, you will be given a report on how the expedition itself progressed.
A failed expedition is not the end of the world, as you can repeat them as much as you want, and as much as you can afford to. however, bear in mind that the costs are not only monetary but societal as well.