In 1955, President Dwight Eisenhower approved a plan to orbit a satellite during the International Geophysical Year, an international scientific effort involving scientists from 67 countries to advance studies of Earth. The Soviet Union launched Sputnik 1 on October 4, 1957, and Sputnik 2 on November 3, 1957, while the United States' first satellite attempt, using a Vanguard rocket from Complex 18 on December 6, 1957, rose four feet before exploding. The United States entered the Space Age at 10:48 p.m. on January 31, 1958, when a Juno 1 rocket lifted off from Pad-A at Launch Complex 26 carrying Explorer I, the nation's first satellite to successfully orbit Earth. The countdown was conducted from the Launch Complex 26 Blockhouse, and the mission was a cooperative effort by the Army Ballistic Missile Agency, the U.S. Air Force, the Jet Propulsion Laboratory, and other academic and aerospace entities. Weighing 30 pounds, Explorer I carried instruments to measure temperature, micrometeorite impacts, and radiation, and its data confirmed intense radiation areas around Earth that were named the Van Allen radiation belts for Dr. James Van Allen, who designed the satellite's equipment. Explorer I transmitted data for 105 days, completed 58,376 orbits around Earth, and re-entered the atmosphere and burned up in 1970. Complex 26 also launched bio-flights to test whether life could be sustained in space, sending Gordo on December 13, 1958, and Able and Baker on May 28, 1959. It also served for numerous Jupiter missile launches in NATO's combat training program, with Italian and Turkish missile crews using the facility from 1961-1963. Complex 26 hosted 36 launches from 1956-1963, and after its deactivation the Blockhouse opened to the public in February 1968 as part of what is now known as the Air Force Space & Missile Museum.