NASA has always been adept in generating publicity for itself and its activities. Ever since the beginning of the space age, it has found ways to generate headlines. Here is the most recent example. Should its new plane prove to be as quiet as planned, it still won't guarantee that plane manufacturers will build the craft and airlines will buy it. The promise of supersonic air travel has been short-circuited by inadequate technology and physics for decades. There is no guarantee this test vehicle will dampen sonic booms as planned. Still, the contract to build an X-model is news, and NASA has once again proven its worth to the American public. Smart publicity.