They hired the mod creator (as an artist) and, from the Factorio Friday Facts blog posts[1], the expansion has some inspiration from the space mod but is not the same.

[1] https://www.factorio.com/blog/

Oh, that is amazing! Thanks for pointing me to the blog!

If you like Factorio and are at all interested in game design I can highly recommend every one of those blog posts.

It’s amazing how time and time again a they describe a feature and you’re like wow this is perfect and then later they’re like “here’s how to fix all the problems you don’t even notice”.

The mod is older, and they hired the modder to work on the expansion. From the blog posts the expansion is a lot closer to vanilla then the complex mods.

The factorio team hired the person behind the space exploration mod to integrate it into factorio.

Earendel was employed by Wube in February 5, 2021

https://factorio.com/blog/post/fff-365