A "blacked-out" military installation in use during preparation for the 3rd Bugger invasion. The albedo of Eros at that time was only slightly brighter than a black hole.

Eros served as an advance bugger installation during the 1st invasion. It was the bugger's who first "blacked-out" Eros, which is what drew human attention to the planet. Terran philosophers watched as the planet grew dimmer and dimmer, until it disappeared from sight.

The first expedition to Eros was summarily destroyed by the resident buggers, the crew executed and the ships dismantled. Finally, the Interplanetary Fleet managed, with great effort, to secure Eros. The conquest of Eros proved to be a "treasure trove" of alien technologies. Gravity manipulation and effective use of stellar energy, as well as the Ansible, were products of finds made on Eros.

During preparation for the 3rd invasion, any civilian adviser or technician brought to Eros was required to remain there indefinitely. Much of IF's riskier strategies was apparent to any visitor to Eros, and quarantine seemed the simplest and most effective security measure.