Once reclaimed through the efforts of the Descendants, constant invasions have brought major operational bases back under Vulgus control.
Albion Headquarters is conducting a reclamation operation to completely annihilate the Vulgus and restore operation sites.
Reclamation Operation is way to replay certain story missions with additional difficulty and rewards. Accessed via a terminal in Albion or through Mission Beacons in the field.
[...] there are Normal and Hard difficulty settings. Both difficulty settings use the same map, but there are big differences in the actual gameplay and content system. While clearing the given mission is the focus of Normal difficulty, Hard difficulty is a mode with a stronger end-game character, providing a bigger challenge and offering distinct rewards based on how the level is cleared.
Hard difficulty features selectable difficulty modifiers. Completing higher difficulties improves chances for better rewards.