Boeing Co. and Elon Musk’s Space Exploration Technologies Corp. will split as much as $6.8 billion in federal funding to help the U.S. The contract to ferry astronauts to the International Space Station will pay a maximum of $4.2 billion to Boeing and $2.6 billion to closely held SpaceX, the National Aeronautics and Space Administration said today. A third contender, Sierra Nevada Corp., was shut out.