In Exercise Long Horn, the vast Army-Air Force mock war in Texas, the green-clad Aggressor forces had just seized a position deep behind the defenders' lines and were massing for a new attack. Suddenly a blank mortar shell exploded over the invaders' heads with a roar and a burst of smoke. The umpires stunned the Aggressors with a terse ruling: 1,600 of their men had just been put out of action; the exploding shell symbolized a devastating hit by a revolutionary new weapon, atomic artillery.
This week the U.S. Army and the Atomic Energy Commission confirmed what Exercise Long Horn hinted at. The atomic bomb, once a massive city-buster suitable only for use in strategic air attack, has been tamed and reshaped as a major new tactical weapon for the U.S. Army. Its bulk has been compressed and slimmed into a workable artillery shell. The shell can be fired with pinpoint accuracy by a new highly mobile atomic artillery piece. The atomic cannon is already in production.
The Green Light. The Army has dreamed of drafting the atom into the artillery ever since it heard about Hiroshima. But the dream was wild and impractical until the atomic scientists discovered how to bring off small, controlled, atomic explosions. Then a young Army ordnance expert who is also a nuclear physicist, Colonel Angelo R. del Campo, drew up some sketches and took them to the AEC laboratories at Los Alamos. Working in high secrecy, West Pointer del Campo spent months juggling the requirements of artillery against the requirements of an atomic charge. (Sample: the mechanical parts of an atomic bomb need only be strong enough to withstand the bumps of turbulent air; the mechanical parts of an atomic shell must be 4,000 times as strong to stand up under the explosion when the gun is fired.) One day Del Campo telephoned his Pentagon bosses: "I've just returned from Los Alamos and the light is green."
Army Chief of Staff J. Lawton Collins hustled the design to a meeting of the Joint Chiefs of Staff. The J.C.S. ran it through the wringer of the interservice Weapons Systems Evaluation Group, headed by able General John E. Hull. The W.S.E.G. approved. The Navy, wise to the ways of big guns, pitched in to help with the construction of the first shell and first gun. The first test (made without an atomic charge in the shell) was a shattering failure, but after subsequent tests were successful, Collins gave the order for large-scale production.
Lineal Descendant. The A-cannon is not designed to replace divisional artillery, the 105-mm. and 155-mm. howitzers. It is what is known as "Army" artillery, a lineal descendant of such famous oldtime corps performers as Long Tom and Big Bertha, a type of heavy artillery brought to the front only for such special purposes as siege action or destruction of an enemy massed for a river crossing. Its use against lesser concentrations would be militarily ineffective as well as prohibitively expensive. At long range the big gun is four times as accurate as the average field piece, and can shoot four types of non-atomic shells.