You're probably familiar with supersonic planes like the SR-71 Blackbird pictured above, which managed to fly at over three times the speed of sound, but imagine this: NASA set aside $15 million to develop a hypersonic plane that could exit our atmosphere at speeds between Mach 5 and Mach 20. The US space agency's not expecting to build it quite that cheaply, of course, and it's not holding out hope for a contractor to build the entire plane just yet -- the organization intends to fund some sixteen smaller science and engineering projects (ranging from "how to build a Mach 8+ engine" to "predicting hypersonic fluid dynamics") a
