Science Advisor to the President War II by President Franklin Delano Roosevelt. Vannevar Bush chaired this office through Roosevelt's death in 1945, and continued under Roosevelt's successor Harry S. Truman until 1951. After the war, President Harry S. Truman replaced the OSRD with the Science Advisory Committee in 1951. The office was moved to the White House on November 21, 1957, by President Dwight D. Eisenhower to provide advice and recommendation in response to the Space Race started by the USSR's launch of the first artificial Earth satellite, Sputnik 1. President Richard M. Nixon eliminated the PSAC in 1973, rather than appointing a replacement for
President-elect of the United States the 25th Amendment. The first instance was in 1973, when Gerald Ford was nominated by President Richard Nixon to succeed Spiro Agnew, who had resigned. The second came in 1974, when Ford, who had succeeded to the presidency following Nixon's resignation, nominated Nelson Rockefeller to succeed him. During both vacancies, the nominee was called Vice President-designate, instead of Vice President-elect, as neither had been elected to the office. As a result of these events, the nation has had two more Vice Presidents than it has had Vice President-elects. While he is currently the 48th U.S. Vice President, Mike Pence was