The U.S. Navy has published a new Unmanned Undersea Vehicle (UUV) Master Plan, the first since 2000. The new plan will serve as a guide for the continued evolution of UUV technologies, increasingly critical components of the 21st century fleet. The plan, completed late in 2004 and approved for publication in January, holds steady on course to develop UUVs' "signature" capabilities-maritime reconnaissance, undersea search and survey, oceanography, communication and navigation aid, and submarine track and trail. At the same time, the plan pushes back the technological boundaries to define a new set of capabilities that will be important going forward. The Navy's new UUV Master Plan depicts four basic classes of tactical UUVs, which are to be developed over the next 10-15 years.