恒星 こうせい かん航行 こうこうじゃなかったです
kō seikankōkōjanakattadesu

Noun
Desu Copula

The polite, past negative form of 恒星間航行

1. Interstellar travel wasn't.; It wasn't interstellar travel.

Past/Perfective
Negative
Polite
Casual Register