O'Keefe became NASA administrator on December 21, 2001 after the United States Senate confirmed his nomination. He came to NASA without formal training in science or engineering (as was the case with James E. Webb who was NASA administrator from 1961 to 1968). O'Keefe's tenure at NASA can be divided into roughly three equal periods, each marked by a single problem or event of overriding importance. In the period December 2001 through January 2003, O'Keefe eliminated a $5 billion cost overrun in the construction of the International Space Station. In 2003, he dealt with the Space Shuttle "Columbia" accident and its aftermath. From January 2004 through February 2005, O'Keefe re-organized NASA to start working on President George W. Bush's newly announced Vision for Space Exploration to send humans to the Moon and Mars.