'space-based' originates from Modern English as a compound of 'space' and 'based'. 'space' originates from Latin, specifically the word 'spatium', where 'spatium' meant 'room, area, interval'. 'base' (past participle 'based') originates ultimately from Greek 'basis' via Latin 'basis' and Old French 'base', where 'basis' meant 'step, foundation'.

'space' entered English via Old French and Latin into Middle English as 'space', and 'base' entered English from Old French 'base' (from Latin/Greek). The compound 'space-based' formed in modern English to describe things having their base or operation in 'space' rather than on Earth.

Initially, 'space' meant 'room' or 'area' and 'base' meant 'foundation'; combined, the phrase originally carried the literal sense of 'having a base in space' and has evolved into the modern adjectival use meaning 'located in or operated from outer space'.