Defiant is getting closer to embarking on a key long-endurance cruise that could have important ramifications for the U.S.

The Defiant will have to pass one final test that comes in the form of a long voyage out on the open seas, facing different ...

Following its christening, the USX-1 Defiant soon will begin an at-sea demonstration of its reliability and endurance. The ...

DARPA christened the USX-1 Defiant, a 180-foot fully autonomous medium unmanned surface vessel built for the U.S. Navy.