The Miraz passage was a trade route between Miraz and Alca. According to a Starfleet Academy simulation scenario, several starships were destroyed passing through Miraz, the warp engine being overloaded, without any sign of attack or malfunction. The Starfleet speculated a subspace phenomenon which would destabilize the core, or a new weapon. USS Excalibur, while escorting the Nicholas, traced a subspace signal from a hidden Klingon starbase responsible for the destruction, equipped with an extensive subspace radio array used as a long range weapon.