Then the Nanodisaster. Out-of-control nanotech-powered swarms and other technological catastrophes arise suddenly and propagate rapidly across the Solar System. Security measures, and retribution against those thought responsible, cause additional death and destruction. Trade and cooperation collapse, governments fall, and wars and rebellions break out. Each attempt to contain the chaos leads to new accidents and new conflicts. Billions die. Most of the survivors shelter behind their defences, refusing all communication and contact. Others take refuge in the relatively unaffected regions of the Kuiper Belt and Oort Cloud. A few attempt to flee the Solar System entirely in hasty new interstellar colonization efforts.