I wonder what game Hata-sensei is playing here. We already know there are ghosts (Father Radiostar for a start), to say nothing of other supernatural entities. But I suppose he could be saving ghosts and such for future use, say around chapter 300.
aaaa I caught up, man I am getting anxious over Tsukasa's plot, at the least pls don't tell me she'll have to leave Nasa which will lead to a B I G sad