From paragraph 4:

Once part of a proud European space agency, this ESA research institute today basically was an archive.

If you are referring to the organization that is currently known as the European Space Agency, then you need to capitalize accordingly when spelling out the full name.

But what was it that was wrong here? Then it hit him, it never snowed in September, not here?

I'm going to suggest that the text be rewritten like this:

But what was it that was wrong here? Then it hit him: it never snowed here in September, did it?