'astronautical' originates from Greek roots, specifically the words 'astron' and 'nautes', where 'astron' meant 'star' and 'nautes' meant 'sailor'. The adjective was formed in English by adding the suffix '-ical' to 'astronaut'.

'astronautical' developed from the modern English noun 'astronaut' (coined in the 20th century from Greek elements 'astron' + 'nautes') with the adjectival suffix '-ical' to produce 'astronautical', used to describe matters of astronautics and space travel.

Initially formed from a literal sense of 'star-sailor', the word's meaning shifted to the technical sense of 'relating to space travel, spacecraft, or the science/engineering of operating them'.