Lockheed Martin's Skunk Works has already begun development on the high altitude SR-72, which will fly at Mach 6—twice the speed of the SR-71—and will be capable of carrying weapons. Unlike the Blackbird, the SR-72 is an armed platform that will be capable of attacking from the edge of space. (sploid.gizmodo.com) さらに...
The link referenced in the squawk post is to Gizmodo, which is certainly not a bad tech news consolidator but its summary article actually is based on the exclusive source in Aviation Week and provides a direct link to that source article.