Rockets on a timetable (Nov, 1950)
Rockets on a timetable
By Richard F. Dempewolff
X IS ZERO; the exclamation point in time when the 58-foot, two-stage “Bumper” rocketâ€”combining a modified V-2 with a 700-pound WAC Corporal riding its noseâ€”will stand on its fiery tail above the new long-range proving ground in Cocoa, Fla., whoosh to the stratosphere and lay itself out for the world’s first long, horizontal stretch above the Atlantic.
No one knows when X will arrive. At . any moment, time may stand still while men, hanging half in and half out of yawning hatches in the side of the four-story monster rocket, hold up the count as they make final adjustments.
“It is X minus 20 minutes. Stand by,” growls the PA system. In the massive concrete blockhouse beside the firing apron, you feel the tension tugging at the pit of your stomach. The “technical director” is clipping orders in gibberish: “Check the bucking voltage … you’re four points down . . . keep, a cheesebox on number three scope . . .”
Through the periscope mirror window in the 14-foot-thick concrete wall you see ladders come down. Hatches are locked. Knots of men move toward the blockhouse. Green lights flick on across a big board, as each department in the launching project indicates readiness. The droning count moves down the minutesâ€””X minus 15, X minus 14, X minus 13″â€”until minutes have run out. Then the loudspeaker punctuates the last tense 20 seconds with the finality of a metronome: “… five … four .. . three . . . two . . . one . . .”
At “five” the engineer in the blockhouse jabs the red “fire” button. An electric current flashes out to the base of the rocket, igniting a pyrotechnic device like a Fourth of July pinwheel. There’s a crack like a pistol shot as the rocket valves leap open. Alcohol and liquid oxygen drop through pipe lines from fuel tanks into the motor, where the pinwheel spews its flame. Wispy vapors curl around the fins. A finger of fire stabs at the launching “pad.” Then, with an uncanny roar, a dazzling fountain of white-hot flame gushes over the concrete in mushrooming waves.
“… ZERO!” The monster quivers, lifts slowly and hangs for one incredible instant on its own tail a few feet above the ground. There’s a frightening storm of noise, like no other sound on earth. Another split second and the pad is empty of all but sound.
Before you can rush out the blockhouse door, the first preview of push-button warfare, and the first successful horizontal Bumper launching from the new 3000-mile proving grounds near Banana River, is over. Already the rocket is in the stratosphere, burning 10 tons of fuel per minute, traveling 2730 miles per hour and trailing a vapor plume. A gyroscopic steering device turns it on its side, to horizontal flight. As the main part of the rocket is spent, the WAC Corporal takes off and continues the flight to its watery finish while the V-2 shell drops to the sea. As they whoosh through the sky, both parts of the rocket send back valuable information to the telemetering stations.
X for this first big long-range rocket in the United States occurred last summer. Most details are still secret. But for any rocket, X is merely a crashing climax to months of preparation, tricky handling of fantastic materials, using equally fantastic equipment in a security-bound, guided missiles business that is strictly Buck Rogers. More than a hundred days before firing, men hunch over drawing boards calculating trajectories, planning, revising, drawing up specifications for parts and instruments. Safety engineers, radar and radio operators, search units, optical scanners, fuel menâ€”all form a vast army of experts marching toward X.
X ceases to be just a mark on a piece of paper on the day a big rocket rolls to the proving ground from the factory. It may come in several ways. V-2s arrive in three sectionsâ€”nose, belly and finsâ€”cradled on three weird flatcars with hayracklike ribs curling up from the sides. Rails lead right into the rocket hangar. The flatcars are pushed together until the rocket pieces butt so they can be joined.
About a week before X-Day, the rocket shell is transported from hangar to concrete launching site or pad. For smaller missiles like the eight-finned Lark or the WAC Corporal, Jeeps or trucks with special racks do the job. Some of these rack assemblies can be jacked up to become portable launchers. The boys just roll to a selected spot on the desert, tilt the rack and “let ‘er go.”
V-2s and Vikings are not so easy. An empty V-2, without its one-ton warhead and 5000 gallons of fuel, weighs 10,000 pounds. You can punch a hole in the “skin” with a screwdriverâ€”it’s only as thick as ordinary aircraft skin, and unsupported except for the motor mounts. To lug this around without damaging it takes some doing. More than a third of the Germans’ V-2s were wrecked before they ever reached wartime launching sites.
The Navy’s big Viking wheels out of the hangar on a special Martin-built carriage. It is an elongated tricycle airplane landing gear assembly, strapped by yokes to the long cylinder. At launching site, a crane hauls up the nose and the tail follows into place, rolling on its rear wheels. This is especially handy on the Navy’s rocket launcher, USS Norton Sound, where heavy, complicated apparatus is impractical. It made possible the record flight of the Viking from her unique launching deck last year.
The V-2 makes its trip to the pad on a Meilerwagen, invented and used by the Germans when they were launching the rockets against England. Still best for V-2 toting, the Meilerwagen is a massive trailer with a steel cradle on its back. The cradle is hinged at the rear of the trailer and equipped with hydraulic lifts capable of raising 10 tons. In the hangar, a crane lifts the nose of the assembled V-2 off its flatcar bed. The Meilerwagen backs underneath the missile, the crane lowers the rocket gently into the Meilerwagen cradle, and off drives the rocket to the launching pad. Once at the site, the “wagen’s” hydraulic pumps go to work, the cradle rises slowly like the big ladder on a fire rig, until the rocket is setting vertically on its four-legged launching platform.
Once the big rocket is pointed skyward, X is in sight. The huge metal scaffolding of the gantry crane, about 60 feet high, is wheeled over the monster. Crews swarm over it like ants. New gantries, like the one at Cocoa, are masterpieces of design. The structural members are used for ladders to reach various sections of the rocket. A handful of men can wheel the vast tangle of featherweight metal tubing on its casters. The whole thing weighs only 600 pounds. It comes in two slices, which clamp around the rocket like a mold. Three of its hinged decks, about 34, 42 and 50 feet high respectively, “drawbridge” down by handcrank around the V-2’s belly.
For a week, the launching site is a beehive of activity. In mobile machine shops at the gantry’s base, machinists turn out precision parts. Signal men at outlying stations check and test equipment. Telemetering films from 30 channels are studied and adjustments made. At night, rocket and gantry lie under the eerie glare of floodlights. Up on the top deck, or “widow’s walk,” shadowy figures install the telemetering devices in the rocket’s high noseâ€”or the secondary rocket, if it’s a Bumper. On the second platform, men’s legs jut from open ports containing pressurization tanks for the fuel, and the maze of electronic controls. One engineer at White Sands has a standing bet that some day a technician will fall in, get lost in the spaghetti, and be locked up inside on X-Day. “He’ll have quite a ride,” he says. On the bottom gantry deck, engineers and fuel men make final adjustments in the cavernous engine. The steering vanes, made of pure carbon to withstand the thousands of degrees of heat blasting from the rocket’s tail, are adjusted with microscopic precision.
About 16 hours before X the ambulance rolls into the launching site, fire fighters move on station in their weird, Martian asbestos suits and the men prepare for a full-scale rehearsal. “Take-off” is prevented only by four small bolts that are enough to hold the rocket to earth under 20,000 pounds of thrust. The gantry is then hauled away, power lines attached and everyone moves to the protection of the fortlike blockhouse with its 14-foot concrete walls and 27-foot-thick ceiling, some 150 feet from the pad. “From the looks of it,” remarks one engineer, “you’d think they expected the rocket might fall on them. That is just what they expectâ€”and it has happened!” One Aerobee at White Sands fell over on take-off and the ensuing blast of white heat from its exploding fuel seared everything for hundreds of yards around.
After the “test hop,” the gantry comes back, and the pace quickens. From his microphone in the blockhouse, the technical director begins to call off the time every 15 minutes. At X minus 20 minutes, it will be every minute; at X minus 20 seconds, every second. Meteorologists have checked weather for optimum flight conditions and at last the moment for firing is set.
“X minus six hours,” blares the loudspeaker. “Check water and cooling systems; fire fighters on station.”
No one expects that in six hours the rocket will take off. At any point up to within a minute or two of firing, the count may “hold” for a recheck. “Hold at X minus 18,” the speaker may groan. When the failure is remedied, minutes or days later, the count will pick up again at “18.” This can be nerve-wracking. A draftsman at White Sands recalls a Bumper launching that had everyone jittery. “X minus two minutes,” grated the loudspeakerâ€”then, “HOLD IT!” Something was jammed up in telemetering. The count backed up to X minus 10, then 20, then one hour. Three times it came back to two minutes. The rocket finally took off a week later.
At about X minus four hours, crews dressed from head to foot in plastic suits and hoods, like men from another world, move into the area with trucks carrying queer metal tanks. This is hydrogen peroxide which, when combined with another chemical, suddenly becomes steam that turns the rocket’s high-speed fuel injector turbines. It’s tricky stuff. Almost any foreign matterâ€”including skinâ€”that touches it, will set it off. A handful of sawdust thrown in a container of it will cause a fantastic explosion. “Somebody spilled some on a Jeep at White Sands,” recalls Dr. H. E. Newell, head of the Rocket Sonde Research Branch of the Navy’s program (which has nothing to do with the Army’s V-2, but includes the big Viking) “and POOFâ€”no Jeep.” It runs off Pliofilm like water, however, and the sterile alloy drums lined with inert material in which it is carried make it as easy to handle as cordwood. But it’s treated like nitroglycerin just the same. So is the nitric acid, used as an oxidizer for some rocket fuels. While not explosive, you can see what nitric would do simply by dropping a penny in it. The penny disappears in a cloud of ugly green fumes.
“X minus three hours and 30 minutes,” drones “the voice,” and fueling goes onâ€” all of it dangerous and requiring vast precautions. Tanks of soda for neutralizing . acid can be seen everywhereâ€”including each deck of the gantry. Smoking is prohibited within 75 feet of the area; sandbags surround portable equipment. Firemen stand by with water and foam hoses ready to flood the entire place at an instant. The big rocket’s 2500 gallons of ethyl alcohol are poured in from tank trucks. No one worries about the alcohol. It’s pretty stable.
“X minus three hours. Move oxygen into area, move tool trailer behind blockhouse.”
In rolls the ingenious vehicle which hauls the frigid liquid that will make the alcohol burn. It’s a regular truck chassis on which is a 3000-gallon Thermos bottle that looks like a cement mixer. Inside the big steel cylinder are huge bottles, fitting one inside the other. The oxygen is in the innermost. One odd property of the 247-de-grees-below-zero liquid is that it insulates itself by forming a wall of frost on the outside of its containers. If tightly confined, the constantly “boiling” fluid will build up pressure and burst its container. Hence, it must be vented. But that pressure can be useful, too. The truck spews vapor trails through its vents only until loading time. Then the vents are closed, and the pressure is used to force oxygen into the rocket.
Finally, fueling is completed; checks are almost finished. The loudspeaker takes on a deeper more concise tone: “X minus one hour.” Slowly, the gantry rolls back and the rocket stands alone against the sky, a white plume of venting oxygen pouring skyward from a hole in its nose. A long pole beside the rocket supports a power cable hooked near the tip, supplying electric power and conserving the batteries inside. This will fall away at launching. Quickly removable “German ladders”â€”square, four-sectioned telescoping affairsâ€”are raised by handcrank against the side for last-minute adjustments. Each section of these odd ladders pulls the next along behind it.
All up and down the range, tension is mounting steadily. Observer stations report readiness by radio and telephone. At one of them, men are tracking through high-powered telescopes. From the instant of launching, the arc described by the swing of their scopes will be automatically transmitted to pens that mark the exact course and landing spot of the rocket on a map of the area. On land-bound ranges, planes scout for stray civilians who might still be within the boundaries.
“X minus 45 minutes!”
Red lights switch to green on the blockhouse control-board panel as Radar Tracking announces readiness. “Dopples,” or sound tracking, switches green. The “Telemetering” light goes green too, indicating that all gear is ready to receive impulses from the soaring rocket, providing a progress report of the trip. “Rocket Controls” blinks greenâ€”and so does “Cut-Off.”
Cut-Off is a fantastic safety system which consists of a detector circuit built into the radar scopes. If the radar loses contact with the rocket in flight, this system automatically detonates a TNT charge in the rocket, destroying it. A lost rocket may never be picked up again. In the early days, one V-2 from White Sands made an unscheduled stop in Juarez and the boys still hear about it. Though they carry no charge, big rockets falling from 100 miles up can blast a 50-foot crater 20 feet deep in the ground.
To double check against a rocket getting away, there’s also a “continuous pressure button,” which is held down under the safety engineer’s thumb throughout the flight. If the rocket veers off its prescribed course, that button can be released and instantly the rocket explodes, no matter where it is.
By “X minus 30 minutes,” all the hundreds of intricate operations involved in the launching project are ready. Everyone is standing by. Months of preparation border on climax. Faces of the men at the blockhouse control panel are grim. A dozen things still can go wrong. “Every rocket is different,” explains Doctor Newell. We’re still experimenting with new systems and firing techniques at every launching. Hence, there’s always cause for new worries and tensionâ€”like the time we rigged a circle of jato units around the base of a big rocket. They were to fire on take-off and set the rocket spinning as it went up. Suppose they didn’t fire simultaneously and the rocket went wild? Suppose they didn’t fire at all? Actually, it worked perfectly, and the rocket bored its way skyward as plannedâ€”but the tension was rugged.”
If anything goes wrong with any of the hundreds of circuits necessary to a perfect take-off, the firing button won’t set off the rocket. Furthermore, there are fast-moving routines followed in such emergencies. They came in handy on one Aerobee at White Sands, Doctor Newell remembers. With only one minute to go, a diaphragm ruptured and hissing acid burst through it, poured to the pad and started a fire at the base of the rocket. Instantly the “fire” button was pushedâ€”to get the rocket out of the way. But automatic controls already had cut the circuit. The button wouldn’t work. Men raced around the blockhouse. Pressure was “dumped” from the rocket by remote control; within seconds water jets poured a Niagara over the missile; firemen standing by moved in with foam and high-pressure hose and added to the drenching; a switch in the blockhouse was thrown, sealing off the booster rocket so it wouldn’t go off separately.
Usually, by the time the loudspeaker intones “X minus 20 minutes,” everything rests on the success or failure of electronic and mechanical equipment. A purplish red smoke grenade goes off, warning all personnel that everything is set.
At X minus 2 minutes, a red Very flare streaks to the sky. There isn’t much anyone can do now. “It is X minus one minute,” drones the speaker, and you can hear a pin drop in the blockhouse. “The next count you hear will be minus 20 seconds. Stand by.” If it’s White Sands or Halloman, men at some 30 stations uprange will be fingering their instruments nervously. If it’s Cocoa, observers way out on the Bahama Islands will be alert for the white vapor streak across the sky that tells them another long-range rocket is streaking horizontally for a new distance record.
“Eight . . . seven . . . six . . . fiveâ€”down goes the buttonâ€”four .. . three . . . two . . . one . . . zero.”.