In 2154, Enterprise NX-01's primary warp coil was damaged beyond repair due to a Xindi attack at Azati Prime. In order to make a rendezvous with Degra on time, Captain Archer was forced to mount an attack on an innocent Illyrian starship for the purpose of stealing their warp coil. (ENT: "Damage") According to Star Trek: The Next Generation Technical Manual (p. 1), 1,200,000 Cochrane-hours was the goal life cycle of the primary warp coils of a Galaxy-class starship between refurbishments, when the development of the class began.