During World War II, the National Bureau of Standards (NBS) played an important role in the Nation's military effort. The Bureau established an ordnance group, and its members were given wide creative latitude to develop and improve weaponry. One of the ordnance group's chief accomplishments was the development of the radio proximity fuse, which allowed a projectile to explode when in effective proximity to its target rather than on impact. A tiny radio transmitter and receiver powered by a battery or generator, the proximity fuse was triggered by reflected radio waves. The first major combat use of proximity fuses was during the pre-invasion bombardment of Iwo Jima in 1945.
The NBS ordnance group also helped to develop the first guided missile successfully used in combat. Known as the Bat, it was a large bomb mounted in a glider-type of fuselage, with two short wings and a tail. The bomb was guided to its target by a radar device and exploded on impact. NBS designed its aerodynamic and stabilization characteristics and coordinated the civilian agencies working on the project. The Bat was used in the Pacific Theater toward the end of the war. It was used primarily against Japanese ships because its radar could easily pick up the image of a ship on a blank ocean.


