The ship, 1, 000 feet long -- about the length of three football fields -- sailed from Port Canaveral on Saturday.

CNN: STORY HIGHLIGHTS

The ship, which is 1, 000 feet long -- about the length of three football fields -- sailed from Port Canaveral on Saturday.

CNN: STORY HIGHLIGHTS

The Homeland Security Committee will hear tomorrow that this unimaginable horror can be triggered by a scenario examined at length by the Commission on the EMP Threat - namely, a ship-launched, ballistic missile-delivered nuclear weapon detonated outside the atmosphere high above the United States.

CENTERFORSECURITYPOLICY: An avoidable catastrophe