The sea-based radar considered a key to the nation's missile defense shield has left Hawaii for its home port of Adak at the end of the Aleutian Chain.
The X-band radar is part of the Missile Defense Agency's $43-billion program and is used to track missile launches. It looks like a giant golf ball sitting atop a 27-story, partially submersible oil rig.
The radar has been in Hawaii for repairs and has never been to its home port. It was on course to Adak more than 10 months ago but turned back to Hawaii after experiencing ballast problems.