Constitution-class Federation starship, registry no. NCC-1672, commanded by Captain Ronald Tracey. In 2268, the Exeter visited planet Omega IV, where Captain Tracey brought back a deadly virus from an ancient bacteriological war which infected his entire crew and reduced them to dehydrated crystals. Having developed an immunity from the planet's atmosphere, Tracey returned to the surface and became involved in the internal struggles there, providing the primitive civilization with phaser weapons. Tracey was discovered by the U.S.S. Enterprise and arrested on charges of violating the Prime Directive.