 Complete the following phrase:  John E. Pickering 27 April 1918  19 September 1997 was an American pioneer in the field of radiobiology, aviation medicine and space medicine and a Colonel in the United States Air Force. He spent much of his career in the Department of Radiobiology, Air University, School of Aviation Medicine at Randolph Air Force Base, Texas. Pickering was involved with the first tests involving nuclear powered aircraft. Pickering co-wrote President John F. Kennedys last official speech before the 