"The Spaceline. By extending a line, anchored on the moon, to deep within Earth’s gravity well"

That's the concept. They could have fit that within in the title of the post.

A pointer to where they compute this in the paper would be helpful. There are a lot of comments to just read the paper because they calculate this or that, but I quickly read the thing through and either missed all these points being covered, or it's not actually considered.