It's a pretty complex and manual process. You need tons of space, and it's usually built with composites. It's pretty challenging to inspect them for flaws once

It's a pretty complex and manual process. You need tons of space, and it's usually built with composites. It's pretty challenging to inspect them for flaws once they are built too. Afaik, they are built in dedicated factories but usually on the same continent (at least!) as where they are going to get installed.