Didn't Earth get consumed by the sun? How could a space ship endure that?
Kaguya's eternity manipulation can here at least make something "eternal" and thus indestructible while she maintains it, people were guessing last year that that's why they still have clothes (artistic license aside). It was also brought up directly in the story by Eirin when she was talking about building that underground research city to create her warp spaceship, she said that Kaguya's power would mean they didn't have to worry about maintenance.
There is something different. Mokou completely losing it with a "Uuuu" cry.
What, this spaceship?Wahhhhhh-! Kaguyaaaaaa!!!Ka-Kaguya?Hey, Mokou! It's been a while.The Sinner of Eternity and the Instantaneous
Houraisan KaguyaUuuu...Huh?Is this a hallucination? How...Before the Earth's gone, Eirin left this behind for me.Wait, are you crying?Wait, don't hug me!!!