So, I'm trying to remember the name of a series of books that features telepaths who contact people with their minds across the galaxy, and send ships. I remember one of the key ones was on a moon in the outer solar system, I want to say Io.
There was different ratings of telepaths, L1s were the most powerful, and extremely rare. 2 L2's that were perfectly matched, or maybe 3 L3's, could almost do what an L1 could do. But much lower than that, and they had relatively little power, although they were still matched.
There were multiple books, novel sized.
Also, the books featured a species of aliens who I believe were at war at first, but later they were at peace with humans. In order to help learn about each other, they started small communities where both human and aliens were raised together, so they could better understand each other's language.