I never accepted that Khan Noonian Singh's Botany Bay actually launched in the 1990's; only that the beginnings of DY-class technology were in that era. McCoy rolled his eyes when he mentioned "the Eugenics Wars", which could've started in the '90's by killer Al Quaeda Doctor Ayman al-Zawahiri, for all we know. Word is, he's hiding out in Pakistan... Anyway, the notion of "Eugenics Wars" suggests a string of conflicts, which could've started with leftover Cold War conflicts including Al Quaeda. Maybe the final conflict was in the 2050's. Khan's ship could've left anytime between now and then.