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Propulsion Problem. As now planned, the body of the ICBM will have two alternative "configurations" (shape and arrangement of rockets), one to be built by Convair, the other by Martin. The propulsion problem is considered fairly well in hand, and the industrial hero of rocket propulsion is North American Aviation, Inc. Back in the early postwar years, North American got a contract to develop a long-range, air-breathing, (i.e., winged) missile. The best chance seemed to be for a high-performance plane propelled by a ramjet engine at very high altitude and at two or three times the speed of sound. Since ram-jets have no thrust at all when standing still and not much thrust below the speed of sound, a rocket booster was necessary to get the winged missile (now called the Navaho) up to cruising speed. North American found that HO one was interested in developing rocket motors big enough for the Navaho's booster, so it did the job itself, starting almost from scratch and building its own test facilities in the Santa Susana mountains, 40 miles northwest of Los Angeles.
Santa Susana is a fabulous place, a three-sq.-mi. area fenced and guarded, and crowded with up-and-down ridges dotted with rounded red rocks. A steep road winds over a pass and plunges into an amazing array of futuristic structures. There is no natural level land. Big buildings, fat tanks and weird testing equipment perch on crags or nestle in rocky crannies. New construction is being pushed with frantic urgency. The whole place swarms with hard-hatted workers. Bulldozers climb like mountain goats, pushing parts of the mountains ahead of them. A plant is in construction that will take from the air 600 tons of liquid oxygen per day.
Tucked away in ravines, to reflect sound upward, are the massive steel structures where rocket motors are put through their paces. Their beams are as strong as the piers of suspension bridges, and they are "fishhooked" into the rock to keep them from being lifted by the thrust of the rockets. Seven hundred feet away are squat blockhouses with periscope windows. When a powerful motor is under test, an enormous flame licks down the precipice, sometimes bounding upward in a billow of yellow fire. A sound like the rumble of doomsday rolls among the rocks, making the flesh quiver like shaken jelly.
The rocket motors responsible for all this commotion are dainty, five-foot things, some of which have the silhouette of a slim-waisted girl in a dancing dress. Around their bodices (combustion chambers) and flaring skirts (tail cones) are parallel metal strengthening bands that look like decorative ruffles. When stored in the open, they often wear translucent fichus of plastic film. A strong man can put one of them in the trunk of a car, but these frail dancing girls of space could lift 40 cars; when they are flying at full speed, they develop millions of horsepower, more than the top energy production of Hoover Dam.