Now that we have private astronauts or are on the verge of having them, NASA should be redefined as having the missione of expanding knowledge, but not via manned flight, at least for a couple of decades. Let the "adventure" be funded by private enterprise, which can best recoup the cost via marketing. That Man can go to space safely has already be proven by NASA and others. The other way of looking at it is that NASAs unstated mission was to subsidize Cold War defense research, to make strong domestic industrial aeronautics industries. If it spent its budget on private space flights it will get a bigger bang for the buck, foment an industrial rennaissance in America at least, and do serious science on its own, with robots. Privatize the risk of human casualties, remove it from the politicians concerns.