Free of the Empire's enslavement, the humans on Coruscant began investigating the technology their Rakata masters had left. Although they couldn't use the Force-powered machines, the humans learned enough to make tentative forays into space, using slower-than-light vessels manned by crews kept in suspended animation for decades at a time.
Slowly, humans began to colonize new worlds: Alsakan, Metellos, Alderaan. The first explorers to Alderaan discovered the remains of strange insect nests, later known to be built by the Killiks.
The pureblood Sith species on Korriban, having survived both the Infinite Empire's onslaught and a bloody civil war after the death of their king, also became intrigued by the machines the Rakata left behind. Suddenly a spacefaring civilization, the Sith species left Korriban and eventually established a new capital on the planet Ziost.