Humanity stands at the threshold of a discovery that no existing law was written to govern: the finding of life beyond Earth. Space missions now make the detection of extraterrestrial microbes a question of when, not if, yet the foundational treaties of the space age—drafted when such a prospect seemed safely distant—offer almost no guidance on ownership, biosecurity, or the weaponization of alien biology. As with so many pivotal moments in human history, the frameworks we inherit may prove far too small for the world we are about to enter.