| Nominative | astronaut |
| Genitive | astronauta |
| Dative | astronautovi; astronautu |
| Accusative | astronauta |
| Vocative | astronaute |
| Locative | astronautovi; astronautu |
| Instrumental | astronautem |
| Nominative | astronauti; astronauté |
| Genitive | astronautů |
| Dative | astronautům |
| Accusative | astronauty |
| Vocative | astronauti; astronauté |
| Locative | astronautech |
| Instrumental | astronauty |