Following the outbreak of
World War II, Smith obtained a position at the
Johns Hopkins Applied Physics Laboratory Maryland. As a civilian scientist, he was assigned to the
Army Air Force in
England, and planned railway targets for airstrikes in support of
D-Day. For this work he was presented with the
Medal of Freedom. He studied and reported on the dangers of
radioactive material contamination from
nuclear weapons. In 1949, Smith at Oak Ridge conducted a study sponsored by the
Atomic Energy Commission (A.E.C.)'s Division of Biology and Medicine, and performed calculations to determine the theoretical number of atomic bomb detonations necessary to achieve significant radiation exposure and radioactive material fallout. In 1951 after the
Ranger and
Greenhouse tests, Smith reassessed the earlier calculations and estimates. He determined that detonation of 100,000
Nagasaki type bombs would be sufficient to achieve the
doomsday effect. With this information, the A.E.C.'s staff of the Division of Biology and Medicine concluded this to be extremely remote and dubbed the study as
Project GABRIEL. ==Project GABRIEL==