Monday, September 7, 2009

September 7: James Van Allen

James Alfred Van Allen
September 7, 1914 – August 9, 2006

James Van Allen was an American space scientist at the University of Iowa. The Van Allen radiation belts were named after him, following the 1958 satellite missions (Explorer 1 and Explorer 3) in which Van Allen had argued that a Geiger counter should be used to detect charged particles.

Van Allen received his Bachelor of Science degree, summa cum laude, from Iowa Wesleyan College in 1935. During his undergraduate years, he studied with Professor Thomas Poulter, a first-class physicist. He tracked meteors, conducted a magnetic survey of Mount Pleasant, and measured cosmic rays at ground level. He earned his master’s degree in solid state physics and his Ph.D. in nuclear physics from the University of Iowa. His doctoral research was on measuring the cross-section of the deuteron-deuteron reaction.

As a staff physicist for the Department of Terrestrial Magnetism of the Carnegie Institution in Washington, D.C., Van Allen worked on developing photoelectric and radio proximity fuzes for bombs, rockets, and gun-fired projectiles. It was here that Dr. Van Allen acquired his interest in cosmic rays.

In 1950 an event occurred that began small but was to affect the future of Van Allen and all his countrymen. In March, British Physicist Sydney Chapman dropped in on Van Allen [and] remarked that he would like to meet other scientists in the Washington area. Van Allen got on the phone, soon gathered eight or ten top scientists (Lloyd Berkner, S. Fred Singer, and Harry Vestine) in the living room of his small brick house. ‘It was what you might call a pedigreed bull session,’ he says. ... The talk turned to geophysics and the two ‘International Polar Years’ that had enlisted the world’s leading nations to study the Arctic and Antarctic regions in 1882 and 1932. Someone suggested that with the development of new tools such as rockets, radar and computers, the time was ripe for a worldwide geophysical year. The other men were enthusiastic, and their enthusiasm spread around the world from Washington DC. From this meeting Lloyd Berkner and other participants proposed to the International Council of Scientific Unions that an IGY be planned for 1957-58 during the maximum solar activity). ... The International Geophysical Year (1957-58) stimulated the U.S. Government to promise earth satellites as geophysical tools. The Soviet government countered by rushing its Sputniks into orbit. The race into space or Space Race may be said to have started in Van Allen’s living room that evening in 1950.
– TIME, 1959

On October 4, 1957 the Soviet Union (USSR) successfully launched Sputnik 1, the world's first artificial satellite, as part of their participation in the IGY.

The first American satellite, Explorer 1, was launched into Earth's orbit on January 31, 1958 on a Jupiter C missile from Cape Canaveral, Florida. Aboard Explorer 1 were a micrometeorite detector and a cosmic ray experiment designed by Dr. Van Allen and his graduate students. Data from Explorer 1 and Explorer 3 (launched March 26, 1958) were used by the Iowa group to make the first space-age scientific discovery: the existence of a doughnut-shaped region of charged particle radiation trapped by Earth’s magnetic field.

Pioneer 3, the third intended U.S. International Geophysical Year lunar probe under the direction of NASA with the Army acting as executive agent, was launched from the Atlantic Missile Range by a Juno II rocket. The primary objective of the flight, to place the 12.95 pound (5.87 kg) scientific payload in the vicinity of the moon, failed. Pioneer III did reach an altitude of 63,000 miles (101 Mm), providing Van Allen additional data that led to discovery of a second radiation belt. Trapped radiation starts at an altitude of several hundred miles from Earth and extends for several thousand miles into space. The Van Allen radiation belts are named for Dr. James Van Allen, their discoverer.

In 1959 TIME magazine credited James Van Allen as the man most responsible for giving the U.S. “a big lead in scientific achievement.” They called Van Allen “a key figure in the cold war’s competition for prestige. ...Today he can tip back his head and look at the sky. Beyond its outermost blue are the world-encompassing belts of fierce radiation that bear his name. No human name has ever been given to a more majestic feature of the planet Earth.”

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