While early sea trials of the Joint Strike Fighter have focused on ship suitability for the U.S. Navy and Marine Corps, a wave of upcoming tests are about to evaluate roles geared primarily for U.K. operations of the Lockheed Martin F-35B short-takeoff-and-vertical landing (Stovl) version. Lockheed Martin, BAE Systems and U.S. and U.K. military test units are set to begin an intensive second phase of envelope expansion flights using the ski jump ramp at the U.S. NAS Patuxent River