9 Kappa-Mu

9 Kappa-Mu is a thirty-kilometre black geodesic sphere orbiting between Terra and Venus, invisible to every sensor except eyes and touch. The Mechanicum named it; nothing has ever scored its hull, and the catacombs may predate the Dark Age. Alpha Legion cells used it as a rendezvous until Archamus's Huscarls raided them in the Solar War.