The US immigration services uses the term Alien, and the US State Department have historically used both.
Given how byzantine the US military industrial complex's paperwork and pretend regulation is someone might have been relying on legislation or paperwork predating the change in word usage, and that that influenced the naming of some program somewhere in the secretive world.
It's also worth noting that such a misconception definitely benefit's the military industrial complex as it draws focus towards something that is not there rather then towards what's actually happening, which again is a very common strategy within military intelligence.
Moreover, when it comes to corps/biz incorporation domestic is in-state, foreign is out of state, and alien is international. presumably if one day one could charter a corporation at an office on Mars it would be extraterrestrial.
Given how byzantine the US military industrial complex's paperwork and pretend regulation is someone might have been relying on legislation or paperwork predating the change in word usage, and that that influenced the naming of some program somewhere in the secretive world.
It's also worth noting that such a misconception definitely benefit's the military industrial complex as it draws focus towards something that is not there rather then towards what's actually happening, which again is a very common strategy within military intelligence.