Lockheed Martin Corp. is the world’s largest defense contractor and has led the Western market for advanced fighter aircraft since securing the F-35 Joint Strike Fighter program in 2001. Aeronautics is the company’s largest business segment, with more than two-thirds of its revenue tied to the F-35 program. Its other segments include Rotary and Mission Systems, which mainly covers the Sikorsky helicopter business; Missiles and Fire Control, focused on missiles and missile defense systems; and Space Systems, which manufactures satellites and earns equity income from the United Launch Alliance joint venture.