Complex sentence: After commissioning in 1967 she underwent a long period of sea trials, culminating in the test firing of a Polaris missile from the USAF Eastern Test Range off Cape Kennedy at 11:15 on 15 February 1968.
Split into simpler sentences: After commissioning in 1967 she underwent a long period of sea trials culminating in the test firing of a Polaris missile. Fired from the USAF Eastern Test Range off Cape Kennedy at 11:15 on 15 February 1968.