John Challens

Wallace John Challens, CBE (14 May 1915 – 1 March 2002) was a British scientist and civil servant. A graduate of University College, Nottingham, he began working at the Royal Arsenal in Woolwich in 1936. In 1939, he was transferred to the rocket department. After the defeat of Germany, he was sent to the United States as part of the British Scientific Mission to work on the V-1 flying bomb and the V-2 rocket. On returning to the United Kingdom in 1947, he was recruited by William Penney for the British atomic bomb project. He led the team that developed the firing circuits for the bomb used in Operation Hurricane, the first British nuclear test. He later developed a neutron generator. He took part in most of the British nuclear tests at Maralinga, and was the scientific director of the Operation Grapple tests in 1957. He subsequently became the AWRE's Assistant Director in 1965, Deputy Director in 1972, and Director from 1976 until his retirement in 1978.