The New Trinidad pirates, based on space platforms over the empty world of New Trinidad, had attacked ships and outposts throughout the Koprulu sector for decades. Disunity from terran civil wars prevented the formation of strong standing militias capable of stopping them.
The shipping conglomerate devoted considerable funds to the Terran Dominion in order to hire groups of mercenaries to remove the pirate threat once and for all. The mercenaries appear to have been successful.
The pirates were introduced (and destroyed) in the map Mercenaries.
The concept seems to have been borrowed from TSR's Alternity game system setting, Star*Drive, another space opera setting. In the Lucullus system on the Verge of settled space, the Union Penates, a notorious criminal group, is headquartered in the habitat dome of Trinidad on the inhospitable planet of Penates (the citizenry must live in domed cities), and one of the mercenary leaders, Commander Hale, is based on Star*Drive character Warthen Hale, ex-President of the Orion League. TSR, the same company that created Alternity, created a crossover product entitled Alternity: StarCraft Edition.