The facility consisted of a labyrinth of winding tunnels and low ceilings, created by the Formics during the Second Invasion. The average age a child would be sent to Command School was 16, but Ender Wiggin was sent there prematurely at the age of 10.
Command School was organized along with the other International Fleet Schools after Mazer Rackham demanded it. The International Fleet decided to put Command School inside the Formic tunnels, with some renovations. Its location was made a secret to the general public, and even ship pilots who traveled to Eros to drop off passengers were required to stay there to keep the secret.
Ender in Exile
With the threat of the Formics gone, the need to keep Eros a secret was gone. The colonists being sent to the abandoned Formic planets stopped at Eros during their journey.