The Defense Advanced Research Projects Agency has given contracts to Lockheed Martin and Northrop Grumman to work on a quiet supersonic aircraft. This technology could eventually feed into the B-X bomber project, intended to produce a new strategic aircraft that would enter service in 2037 and be able to strike targets anywhere in the world. The B-X is to take off at 100,000 pounds (of which 20,000 pounds would be the bomb load) and cruise at Mach-2. It would be able to fly 6,000 nautical miles without refueling. (The Concorde airliner takes off at 400,000 pounds and can cruise at Mach-2 for 3,550 miles; only 28,000 pounds of its takeoff weight is "payload".)--Stephen V Cole