Ring of Gundam (2009)

The story of "Ring of Gundam" takes place in a new era long after the events of the first Mobile Suit Gundam series' One-Year War. In this world setting, a giant 600-kilometer-wide ring now floats in lunar orbit. An Earth Federation Forces member named Eiji discovers an object called "Beauty Memory" buried in a high-altitude, massive rockbed on Earth.

Unfortunately the movie Ring of Gundam is not yet available on HBO Max.