Polestar

Polestars are part of Crew Retrieval. By combining up to four polestars together, the pool of crew available to be retrieved can be narrowed down, from all of those available in the Portal to a much smaller number. With the right combination of polestars, most crew can be retrieved with 100% certainty, although those which share all of their traits, skills and rarity with another crew member cannot. (For example, First Officer Burnham has all traits, skills and rarity in common with EV Suit Burnham and so any combination of polestars which could retrieve First Officer Burnham could also retrieve EV Suit Burnham. The converse is not true, as EV Suit Burnham has the Duelist trait, which First Officer Burnham does not have.)