Pathfinders are the "tip of the spear" for exploring new worlds. While planetary surveying is typically a long-term, multiple-team process, the Initiative found an alternative, thanks to Alec Ryder's AI research: an individual equipped with the best training and technology available, and an AI partner that can run complex studies in seconds and a hundred test simulations a minute. With AI support, Pathfinders can determine within hours whether a planet is suitable for habitation, and direct the Nexus as to what colonist block stands the best chance there.
Pathfinders are trained to improve the viability of potential planets, initiate first contact with unknown species, find suitable outpost sites, and handle any external threats before the first colonist touches soil. The presence of a Pathfinder is a reassurance that a planet can be settled safely and with a high expectation of success.