Exercise Desert Rock

Las Vegas, Nev. had not seen so many soldiers since World War II. Every evening, swarms of shouting, jostling officers and G.I.s from every branch of the service --paratroopers, artillerymen, medics, engineers--roamed the streets and filled the gambling palaces. The hotels were jammed with high brass, and the big silvery transports sweeping down on McCarran Field kept adding to the flood. Then the planes stopped coming in, the khaki-clad Army abruptly vanished. Out on the desert, 65 miles away, 5.000 hand-picked troops were getting their final briefing before Exercise Desert Rock--the G.I.'s introduction to atomic warfare.

Big Brother Explains. One morning before dawn, huge trucks hauled the troops out to the AEC proving grounds. The loudspeaker voice nicknamed "Big Brother" boomed out instructions: sit down, back to the blast, count three after the flash, then swing around, but don't get up. Some of the men played cards, others tried to read, played nervously with Geiger counters, or just stared at the dust-pluming jeeps scurrying from group to group.

A red-tailed B-29 from Kirtland Air Force Base droned overhead. The G.I.s put away their cards. The plane began to circle. Big Brother started ticking off the seconds. The words "Bomb away" came over the loudspeaker.

For 30 seconds, there was the loudest hush 5,000 men have ever heard. The inevitable joker uttered the inevitable "pop," but his voice quavered. Then came a flash that outshone the sun.

With their backs to the blast, the men saw the surrounding mountains stand out in sharp contrast, felt the earth shake and a wave of heat. It was "like someone had sneaked up on me and breathed heavily on my skin," said a G.I. They slowly counted three, turned around and looked at the huge fireball seven miles away (see NEWS IN PICTURES). It was bright red, and churning. Big Brother kept up a calm, steady patter, explaining what was happening. The blast wave rustled by. One paratrooper confusedly stood up too soon. The returning wave knocked him flat. A deep, sharp "whoomp" echoed and rumbled off the mountain walls.

The men listened as Big Brother pointed out every change in color, explaining which gases and rays were being released. They saw the atomic cloud grow and blossom into the familiar mushroom shape.* When the cloud reached its full height and the dust began to settle, the troops were checked for radioactivity and climbed back into their trucks. The mushroom top broke away and passed under the sun, blotting it out. The trucks rolled forward into the haze and the sour smell of burned cacti and Joshua trees.

On the mountains surrounding Frenchman's Flat, the newsmen barred from the proving grounds (see PRESS) watched a 60-m.p.h. gale drive the atomic cloud toward Las Vegas. The AEC said that the cloud traveled at 40,000 ft., but on Charleston Peak a reporter at the 8,000-ft. level said the cloud passed directly over him about 1,000 ft. up. His shoes showed 10 milliroentgens of radiation, his car over 20 milliroentgens (50 to 100 roentgens are dangerous).

On the desert below, the Geigermen and biological experts started into the blast area. A thousand paratroopers of the 11th Airborne Division and other troops followed them in trucks. Combat teams stormed their objectives: command posts, foxholes and gun emplacements with animals to represent the enemy. "No souvenirs, pick up no souvenirs," Big Brother kept repeating.

A Sergeant Sums Up. When they returned to camp, the men were quickly herded into showers. Some were given test forms to fill out. Did you sweat? Did your heart beat fast at any time? Did you lose bladder control? Most of the answers were no. "I wasn't any more nervous than I would be making a jump," answered one trooper. "In fact, I wasn't even that nervous." The paratroopers said that they would not hesitate to jump into an A-bombed area. They began to think of the atom in terms of tactics. Some thought well-dug-in troops could survive the blast. Others wondered if the table-flat target area provided a real test; they wanted to know how the bomb would work in hilly terrain. Veterans from Korea doubted that the bomb they saw would be effective against widely dispersed troops like the Chinese Reds.

The G.I.s who a month ago regarded the atomic bomb as something mysterious and uncontrollable returned from Frenchman's Flat with some cobwebs cleared away. The bomb was neither a scientist's private miracle nor a surefire home-run pinch hitter, but a potent new weapon to be respected and used on the battlefield. They would go back to their outfits with a good working idea of what it could do to them and the enemy.

A master sergeant summed it up: "When I saw that cloud rising at the bottom like fog coming up out of the sea, I began to get the idea of what atomic warfare might be like."

* The story was going around Las Vegas last week that two Indians were sending smoke signals out on the desert, when they saw one of the atomic-bomb blasts. "Damn," said one, pointing out the mushroom cloud, "I wish I'd said that."

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