NASA on Tuesday announced plans for a supersonic X-plane. The space agency announced that Lockheed Martin won the $247.5 million contract to build the plane — the Low-Boom Flight Demonstrator (LBFD). In a news conference, officials said the goal of the LBFD is to make supersonic flight over land quieter. If accomplished, that could allow commercial routes to be used for faster-than-sound flights. — GEEKWIRE This story is developing.