ISS Excalibur (NCC-1664)

In the mirror universe, the ISS Excalibur was an Imperial Starfleet vessel in service in the 23rd century.

In 2268, the Excalibur was ordered to test the new M-5 multitronic computer that had been developed. One of the tests was to participate in wargames against several other starships, including the ISS Enterprise. During the wargames, the M-5 computer supposedly malfunctioned and launched an assault with full weapons power against the Enterprise. The Enterprise was able to survive the assault, and later Captain Spock suspected it was an attempt to assassinate him. (TOS novel: Glass Empires: The Sorrows of Empire).


 * It is possible that the ISS Excalibur is the mirror universe counterpart of the USS Excalibur, a Constitution-class starship, in service in the 23rd century.