Scope: what that description requires in unmodded FTL.

Set up the correct attempt

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The description names the Kestrel Cruiser, so the six aliens have to be aboard that ship; aliens aboard any other ship do not count. It does not list which aliens qualify. Steam achievement list

Count kinds, not individuals

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The description asks for six unique aliens, so several aliens of the same kind count only once toward the six. Steam achievement list

Keep all six aboard at once

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Because the description says "simultaneously", all six have to be aboard the Kestrel at the same moment. Six different aliens gathered over a whole run do not meet that condition if some of them die or leave before the last one comes aboard, and losing the only alien of one kind lowers the count again. Steam achievement list Keep a written list of the kinds aboard and protect them during fights.

Confirm completion

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Check the platform achievement list for The United Federation. On 18 October 2026, Steam's global achievement statistics showed 16.1% of FTL players with it. Steam achievement list

For keeping the Kestrel and its crew alive, Tips for Beginners covers pausing to give orders, crew care and when to escape a fight, and Power and Shields covers ship power and shields.