NASA's green supersonic dart, courtesy a design team at Lockheed Martin, isn't all conceptual looks and aggressive lines, as there's an environmental angle—pardon the pun—that's present here too:
Thanks to an "inverted-V" engine design, which places the propulsion under the wings, the team has successfully, in simulations and sketchpads, managed to lower the level of sonic booms, increase range and payload, and address hazily defined "environmental goals"—which we can probably surmise means it flies faster and more efficiently than today's flying tin cans on less fuel.
This green lawn dart was actually presented back in April, at the NASA Aeronautics Research Mission Directorate, but I'm a sucker for the future and flying things, and this is definitely that: Service, if it happens, would not occur until a 2030-2035 timeframe.
Hey, it's a ways off, but I figure it'll be ready to jet me off to my retirement home on the Moon by then. Small victories, right? [Tom's Astronomy Blog]