Strategic Defence Initiative
From ShireWiki
The Strategic Defence Initiative (SDI) is an agency of the Order of Decima tasked with the defence of the air space and territory of the Imperial Republic against attack by ballistic missiles or other weapons of mass destruction by external forces.
It's existence and operational effectiveness has been continually challenged by the Imperial Shirerithian Air Forces who aspire to gain control of its network of radar sites and anti-ballistic missiles.