An unmanned minehunting vehicle developed by Lockheed Martin Corp ( id="symbol_LMT.N_0"> LMT.N ) has shown improved reliability in new tests, moving it a step closer to use on U.S. warships, Navy officials said on Thursday. An improved version of the Remote Minehunting System has completed 850 hours of testing, paving the way for 10 weeks of development and operational testing this fall, which should allow the system to go into use in 2015. "Ultimately, this system is going to take sailors out of the minefield," Steve Lose, the Navy's program manager for the Lockheed system, told Reuters in a telephone interview. Hunting for mines in harsh, murky waters is a critical mission for the Navy. It is keen to shift that work to unmanned systems and keep sailors out of harm's way. Sea mines are inexpensive weapons that are readily available to terrorists, rogue nations and potential adversaries. Lockheed's Remote Minehunting System combines a diesel-pow