Ilum Endurance Datacron Location
This Datacron unlocks the codex entry - Galactic History 84: The G0-T0 Coup
This datacron holds unheard of power and knowledge collected by an ancient race. You access its power and discover writings which are clearly only one small piece of a massive galactic history:
During the Republic's weakened period after the Jedi Civil War, Aratech Systems had produced G0-T0 droids with hugely sophisticated programming designed to administer entire worlds. The G0-T0 droids were also given an additional order: find ways to restore the Republic while remaining within all legal boundaries. The conflict between these two factors caused at least one G0-T0 droid to break its programming and go rogue, choosing to strengthen the Republic by any means necessary.
Other G0-T0 droids took more drastic measures. Sixteen of the droids in the Gordian Reach established dictatorships on the worlds they administered, eventually declaring the region an independent territory named "400100500260026." Supreme Chancellor Cressa was forced to deploy the Republic military to reclaim the Gordian Reach. The campaign was a widely publicized success, though not all of the rogue droids were accounted for.
How To Retrieve This Datacron
This Datacron is located in a canyon in the center of Ilum (Screenshot 1 & 2) and much like the other Datacrons on Ilum, is extremely easy to get. There are two ways to get to this Datacron, the first way is to jump down into the canyon (don't just jump straight down, jump from ice ledge to ice ledge so you don't die) and the second way is to take an elevator down. I prefer just falling down into the canyon and then either using Quick Travel or taking the elevator back up.
Take into note that if you're Republic you will want to take the eastern elevator up and if you're Empire you'll want to take the western elevator. If not you'll be fighting some mobs when you come up.