Physicist James Van Allen, who is best known for discovering bands of intense radiation surrounding the Earth that were later named in his honor, died Aug. 9. He was 91.

Van Allen’s 1958 discovery of Earth’s radiation belts using the U.S. Explorer 1 spacecraft was just one highlight of a career devoted to unmanned space exploration. In 1973 he led the first survey of Jupiter’s radiation belts with the Pioneer 10 spacecraft, and in 1979 discovered and surveyed Saturn’s radiation belts using Pioneer 11.

While exploring the radiation belts of the solar system, Van Allen also was a professor and head of the University of Iowa’s Department of Physics and Astronomy, where he served from 1951 to 1985, when he retired.

Born in Mount Pleasant, Iowa, Van Allen graduated with his bachelor’s degree in physics from Iowa Wesleyan College in 1935 and later went on to earn his master’s and doctorate at the University of Iowa in 1936 and 1939, respectively.

In the early 1940s, Van Allen helped develop radio proximity fuses, which were used as detonators to defend naval ships. In November 1942, he was commissioned as a naval officer and served 16 months in the South Pacific as an assistant staff gunnery officer.

In 1946, he returned to research at the Johns Hopkins Applied Physics Laboratory, Laurel, Md., leading experiments on V2 and Aerobee rockets.

“His teaching prowess was legendary, his research was defining and his collegiality and service were unmatched,” Gary Fethke, interim president of the University of Iowa, said in the university’s Aug. 9 release announcing Van Allen’s death.

From 1982 to 1984, Van Allen served as president of the American Geophysical Union (AGU), from which he received the John A. Fleming Award in 1963 and the William Bowie Medal in 1977 – both for his contributions to geophysics. In 1994, he was presented a lifetime achievement award by NASA commemorating his 80th birthday and the 75th anniversary of the AGU.

Van Allen is survived by his wife, Abigail Fithian Halsey II Van Allen, his five children, Cynthia Van Allen Schaffner of New York City; Margot Van Allen Cairns of Vancouver, British Columbia; Sarah Van Allen Trimble of Washington; Thomas Van Allen of Aspen, Colo.; and Peter Van Allen of Philadelphia – along with seven grandchildren.