How is victory decided when two civilizations reach Alpha Centauri in the same year?

Solution 1:

If they both have the same year of arrival, the one that arrives first wins. Freeciv tracks flight times as decimals, not integers, so a ship with a 15.2-year flight time beats one launched a year later with a 14.4-year flight time.

If both ships have identical arrival times (which pretty much requires identical ships launched the same year), turn order is used as a tiebreaker: the civilization that would take their turn first is the winner.

Victory is evaluated at the start of each year, and there are two things that can preempt a spaceship victory: hitting the turn limit, or a civilization winning through cultural domination (if it's enabled).