MELBOURNE, Fla.—In 2024, L3Harris Technologies [LHX] backed out of a partnership begun two years earlier to develop a refueling boom for Embraer’s [EMBJ] KC-390 tanker, but on Thursday Northrop Grumman [NOC] and Embraer announced the signing of a memorandum of understanding at Northrop Grumman’s site here to develop a KC-390 autonomous fixed refueling boom to supplement the aircraft’s probe and drogue. Northrop Grumman is not a complete newcomer to the aerial refueling arena, as the company’s X-47B demonstrated probe and…