astrodynamical

The story

1. Proto-Indo-European*h₂eHs-
2. Proto-Indo-European*h₂stḗr
3. Proto-Hellenic*astḗr
4. Ancient Greekἀστήρ (astḗr)
5. Ancient Greekᾰ̓́στρον (ắstron)
6. Englishastro-
7. Proto-Indo-European*dewh₂-
8. Proto-Hellenic*dunamai
9. Ancient Greekδῠ́νᾰμαι (dŭ́nămai)
10. Ancient Greekδύναμις (dúnamis)
11. Ancient Greekδυναμικός (dunamikós)
12. Frenchdynamique
13. Englishdynamic
14. Proto-Indo-European*h₂el-
15. Proto-Indo-European*h₂élisder.?
16. Englishdynamical
17. English todayastrodynamical

From astro- + dynamical.