|The Vice-president of the United States becomes president upon the death, resignation, or removal of the president, should he or she accept the position. He or she is also the president of the Senate. In general, however, the U.S. Constitution does not grant executive powers to the vice-president. The vice-president normally performs duties assigned by the president and acts as his agent and advisor. The Vice-president also serves as the Chairman of the National Aeronautics and Space Administration (NASA).