The story
- Proto-Indo-European*h₂eHs-
- Proto-Indo-European*h₂stḗr
- Proto-Hellenic*astḗr
- Ancient Greekἀστήρ (astḗr)
- Ancient Greekἄστρον (ástron)
- Frenchastro-
- Proto-Indo-European*(s)neh₂-
- Proto-Indo-European*néh₂us
- Ancient Greekναῦς (naûs)
- Ancient Greekναύτης (naútēs)
- Frenchastronaute
- Frenchastronautique
- English todayastronautics
From French astronautique (“astronautics”) + English -ics. By surface analysis, astro- (“space”) + nautics (“navigation”).
Etymology from Wiktionary, CC BY-SA 4.0.