John Challens, 86; Created Firing Circuits for British Atom Bomb

John Challens, the scientist who created the electrical firing circuits that detonated Britain’s first atomic bomb, has died at 86, his family said Tuesday.

Challens collapsed while playing golf in his hometown of Basingstoke on March 1 and died soon after of a heart-related illness, his son Bob Challens said.

Challens was one of a group of scientists who worked in secret at the Atomic Weapons Research Establishment at Aldermaston, now the Atomic Weapons Establishment, created in 1950 by Britain’s then-Labor government to develop a nuclear deterrent.

Britain had been forced to go it alone after the United States stopped all collaboration in the atomic field, limiting Britain’s access to nuclear weapons material and to the knowledge needed to produce the weapons.

On Oct. 3, 1952, in the Monte Bello Islands off the northwest coast of Australia, Challens and another scientist made the final checks on the bomb, which had been loaded aboard the frigate Plym. The device was detonated by the electronic firing circuits that he had invented.

Born in Peterborough in eastern England on May 15, 1915, Challens studied at University College in Nottingham before joining the War Office in the 1930s to research the physics of heavy guns.

In 1939, he worked on missile guidance systems at the rocket development establishment at Aberporth in western Wales, and after World War II he joined the British team that investigated Germany’s V1 and V2 buzz bombs.

In 1947, Challens was recruited to work on Britain’s atomic project by William Penney, who had worked on the Hiroshima and Nagasaki bombs.

In the 1950s, Challens took part in British nuclear tests in Australia and later invented an electronic initiator to replace polonium as a firing agent.

In 1959, he became head of development at the Atomic Weapons Research Establishment, producing new warheads for the Royal Air Force and Royal Navy. He became deputy director of the agency in 1972, and later helped to modify the Polaris submarine’s nuclear missile system so that it could penetrate Soviet defenses.

Challens is survived by his second wife, Norma, and two sons by his first marriage.