The phrase 'permanently-stationed' is formed from 'permanently' (from Latin 'permanere', meaning 'to remain to the end') and 'stationed' (from Latin 'stationem', meaning 'a standing, position').

'Permanently' and 'stationed' were combined in modern English to describe someone or something assigned to a place for a long duration.

Initially, 'stationed' simply meant 'placed' or 'assigned', but with 'permanently', it evolved to mean 'assigned for a long or indefinite period'.