The high-altitude maritime surveillance UAV Northrop Grumman has been developing for the U.S. Navy since 2008, the MQ-4C Triton, is almost ready to embark on its first operational assignment to the island of Guam in the Pacific. The Navy has been constructing a massive hangar and maintenance facility at Andersen AFB there, one large enough to shelter four of the gliderlike aircraft against the tropical rains that prevail from July to November.