Why NASA's space program should be funded by the government?

NASA was created by Congress and and operates under a Federal Statute (law). A common misconception is that it is a large agency and its operations are performed by NASA employees. In fact, NASA is a relatively small organization, and the bulk of its centers and operations are performed by civilian Aerospace contractors. The debate on "privatizing" NASA is ridiculous, since private companies essentially run the space program anyway. NASA just administers it.

The Space Program is only one of NASA's functions; by law, its mandate is to oversee the space program, as well as aeronautics and aerospace research.