In another blow to Boeing Co.’s battered defense business, the U.S. Air Force on Thursday tapped rival Lockheed Martin Corp. for a contract potentially worth more than $3.5 billion to build a new generation of global positioning satellites. Chicago-based Boeing, which has a huge workforce in Southern California, would have made the satellites in El Segundo. The loss of the contract, known as Global Positioning System IIIA, was Boeing’s third high-profile defeat in as many months. The company lost a $35-billion contest to build aerial refueling tankers for the Air Force in February and a $3.74-billion award to build unmanned spy planes for the Navy in April. For the full story visit http://www.latimes.com/business/la-fi-satellites16-2008may16,0,5434942.story