The Space Shuttle

Although most people do not think of it as such, the space shuttle is a launch vehicle. One of its purposes is to carry satellites and space probes into space. The space shuttle is a combination of different types of rockets working together.

The shuttle itself has liquid-fuel engines that burn liquid hydrogen and liquid oxygen. When the engines are running, all that comes out is superheated steam. If you look closely at a photo of a shuttle launch, you will see that it looks as though nothing is coming out of the shuttle's main engines. There is no smoke at all but only the faintest, bluish flame. That is because steam is an invisible gas.

Fuel and oxidizer for the shuttle's main engines are carried in a huge external tank attached to the underside of the shuttle. The space shuttle carries no fuel on board. As soon as it has used up the propellants in the tank, the tankis discarded. (This happens very quickly. If water, instead of fuel, were pumped by the

Liquid Hydrogen Space Shuttle

This photo, taken during the launch of a space shuttle, illustrates a major difference between two types of rocket motors. The two solid-fuel boosters attached to the sides of the large orange main tank produce an intense flame and thick clouds of smoke. The three main engines of the shuttle, however, produce only a bright glow and no visible flame at all. This is because the main engines burn hydrogen and oxygen. The only by-product of this combustion is water, so what you see coming from the main engines is nothing more than superheated steam.

This photo, taken during the launch of a space shuttle, illustrates a major difference between two types of rocket motors. The two solid-fuel boosters attached to the sides of the large orange main tank produce an intense flame and thick clouds of smoke. The three main engines of the shuttle, however, produce only a bright glow and no visible flame at all. This is because the main engines burn hydrogen and oxygen. The only by-product of this combustion is water, so what you see coming from the main engines is nothing more than superheated steam.

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Shuttle Rocket Composition Liquid Oxigen

main engines

main engines

The space shuttle is a complex, multistage rocket. The shuttle itself carries no fuel or oxidizer. Instead, its main engines are supplied with liquid hydrogen and liquid oxygen from a huge external tank attached to the belly of the spacecraft. Two solid-fuel strap-on boosters are attached to the sides of the tank. These boosters are jettisoned as soon as their propellant is burned up. Once the external tank is empty, it, too, is discarded.

three main engines, an average family-sized swimming pool could be drained in twenty-five seconds). From then on, the shuttle carries no fuel. When it returns from space, it is an unpowered glider.

The big boosters strapped onto the sides of the shuttle are solid-fuel rockets. They are made of exotic materials, such as carbon fiber, and use modern fuel mixtures. But the solid-fuel boosters are not too different from the rockets that Congreve or Hale made nearly two hundred years ago. They are essentially enormous metal tubes packed with fuel. A

central hollow core allows the fuel to burn evenly. And like a Congreve rocket, once the solid-fuel boosters are ignited, they can be neither turned off nor controlled. They will burn at full force until all of their fuel is spent.

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NASA engineers test a solid-fuel booster for a space shuttle in the 1980s.
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First launched in 1947, the Aerobee enjoyed a successful career of more than thirty-eight years. Meanwhile, the Aerobee carried a wide variety of instruments, adding immeasurably to our knowledge of the upper atmosphere. Aerobees carried some of the first living creatures—mice and small monkeys—to the edge of space. They also took the first color photographs of Earth from space and made numerous important astronomical observations and discoveries. The last Aerobee was launched in 1985.

The successor to the Aerobee was the Viking, developed by the U.S. Navy. Much larger than the Aerobee—at about 46 feet (14 m) long—the Viking was capable of reaching altitudes of more than 150 miles (241 km). The Viking boasted a large number of innovative features, not the least of which was its gimballed engine. Set into a pair of nested rings, the engine could be swung in any direction. Connected to an autopilot, this allowed the rocket to maintain a steady, stable, straight course. This rock-solid stability was extremely important when taking delicate scientific measurements, such as those involving individual stars, where a steady view is essential.

Unfortunately, large liquid-fuel rockets like the Viking are expen-

Aerobee sounding rockets are used to gather information about the upper atmosphere.

sive. At $400,000 per launch (in 1950s dollars), the Viking simply cost too much to be used as a sounding rocket. This was a boon for the development of solid-fuel sounding rockets. One of the earliest developed after World War II was the Deacon, which was only 1 percent of the cost of a Viking to launch. With the help of a booster, the Deacon could carry a 50-pound (23 kg) payload to nearly 70 miles (113 km) above the surface of Earth. This allowed instruments to measure near-space conditions and make observations above the bulk of Earth's atmosphere. This success led to an entire family of low-cost, efficient solid-fuel sounding rockets that used existing rockets by "stacking" them.

Other countries also developed sounding rockets, both solid-fuel and liquid-fuel. The Soviets created a large number of them beginning in the 1950s. The French began launching the liquid-fuel

Kappa Sounding Rocket
The most popular sounding rocket was the two-stage, solid-propellant NikeApache. Large numbers of Nike-Apache rockets were launched by NASA between 1962 and 1980.

Veronique in 1950. The Veronique had been developed, like so many others, from the V-2. It was so successful that it became the French equivalent of the American Aerobee. It was used for decades.

Britain did not develop a sounding rocket of its own until the mid-1950s. The liquid-fuel Skylark was designed by Walter Riedel, who had been von Braun's deputy at Peenemunde. More than 350 Skylarks were launched. Later models, such as the three-stage Skylark 12, carried 770-pound (350 kg) payloads as high as 620 miles (998 km).

Meanwhile, Japan developed tiny solid-fuel rockets, which were just 9 to 12 inches (23 to 30 cm) long and less than 1 inch (2.5 cm) in diameter. They were called pencil rockets because of their size and shape. These tiny rockets provided valuable data on propellants and engine design.

From the pencil rockets grew the Kappa series of liquid-fuel rockets. In 1958 a Kappa 6 carried a 6-pound (2.7 kg) pay-load to an altitude of 135 miles (217 km). Eventually the Japanese developed their successful Lambda series of four-stage solid-fuel sounding rockets. A Lambda rocket launched Osumi, Japan's first satellite.

Australia, India, Canada, Israel, and Brazil have also developed sounding rockets for scientific research. The simplicity and inexpensive-ness of sounding rockets has enabled countries that do not have the facilities to develop rockets of their own to purchase them from other nations. This has given many small countries the ability to participate in important scientific research.

All Kinds of Rockets

Rockets are not limited to scientific research, space exploration, or the military. After the great ocean liner Titanic struck an iceberg in April 1912, its crew desperately tried to summon help by firing signal rockets. The ship carried thirty-six rockets to be used in an emergency. They were the most up-to-date maritime models. They were different from previous signal rockets because they carried an explosive device that created a loud bang in addition to a shower of white stars.

Unfortunately, the crew members who fired the rockets did not do so properly. The international distress signal required that a rocket be fired once every minute. Instead, the crew fired only eight rockets at irregular intervals over the period of one hour. This signaled only that the ship was having problems navigating. Thus, at least one potential rescue ship ignored Titanic's cry for help.

One of the earliest civilian uses for rockets—other than for signaling—was for lifesaving. A lifesaving rocket was used by the British to rescue people from sinking ships. One end of a rope was fastened to a stronghold on the rescue vessel, while the other end was attached to a rocket. When the rescuers shot the rocket, the rope was propelled across the water and landed on the sinking ship. Passengers and crew could use the rope to make their way to safety.

Although Congreve designed one of the earliest lifesaving rockets, they were refined by other inventors such as John Dennett (1790-1852).

Dennett's rockets were fired from lightweight, portable stands that could be set up and aimed by anyone. Some of his rockets were designed to snag themselves in a ship's rigging or to attach themselves to parts ofthe wreck. This was in case the ship's crew was too exhausted to attach the line. Thousands of people have been saved using these rockets, and modern forms of lifesaving rockets are still used.

In the nineteenth century, whaling was an important and lucrative industry because oil from whale blubber was used to fuel lanterns. Whalers used rockets to shoot harpoons from the decks of small boats into the bodies of whales. Successful rocket attacks on whales were recorded as early as 1821. The captain of the Fame boasted that he had caught nine whales with rocket harpoons.

Years later, a whaling rocket was patented by Thomas Welcome Roys, a U.S. whaling captain, and Gustavus Adolphus Lilliendahl, a

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When lifesaving rockets were used, a light line was carried by the rocket to the ship in distress.

fireworks manufacturer from New York City. Thinking that the Roys-Lilliendahl rocket harpoon was not powerful enough, John Nelson Fletcher and Robert L. Suits designed their own rocket in 1878 and began selling it. The Fletcher-Suits rocket harpoon was 6.5 feet (2 m) long and weighed 32 pounds (15 kg). According to the manufacturers, it could hit a whale 180 feet (55 m) away. It was considerably more effective than a hand-thrown harpoon.

In modern times, rocket-propelled harpoons are rarely if ever used. Whalers instead use harpoons fired by high-powered guns. These are more accurate and don't have to be used at such dangerously close range to the whale as a rocket had to be.

Rockets are also good at making objects move fast. In the early 1950s, an air force doctor named John Paul Stapp was in an air force study of the effects of deceleration on the human body—or the effect

THE WHALE FISHERY.

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This illustration from a nineteenth-century U.S. manual shows the proper use of a rocket harpoon.

THE WHALE FISHERY.

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This illustration from a nineteenth-century U.S. manual shows the proper use of a rocket harpoon.

of coming to a sudden stop when traveling at a high speed. One goal was to increase survival rates in airplane crashes.

So a special rocket-powered sled—dubbed Sonic Wind I—that ran along a track in the New Mexico desert was built. On December 10, 1954, Dr. Stapp strapped himself into the seat. Twelve large solid-fuel motors accelerated him from a standing start to 632 miles (1,017 km) an hour in just five seconds. At the end of the track, scoops built into the bottom of the sled hit a reservoir of water between the tracks. The sled came to a complete stop in just 1.3 seconds.

This created a force on Dr. Stapp's body more than forty times that of gravity, increasing his weight to 6,800 pounds (3,087 kg) almost instantly. Not only did he set a land speed record, Stapp's work helped in developing seat belts and improving aircraft seats, restraints, and other safety devices. This has saved many lives.

Rocket-propelled sleds were used in the 1950s and 1960s to provide data relating to the effects of high acceleration and deceleration on the human body. Top: A rocket sled has been fitted with ten large solid-fuel motors. When these motors are ignited, the sled will race down the track at an extremely high speed. At the end of the run, a scoop on the bottom will hit a pool of water between the tracks, slowing the sled to a stop. Second from top: This rocket sled was used to test escape systems for fighter pilots. Third from top: A sled races down a track under full rocket power. Bottom: Using a combination of water and a parachute, an experimental rocket sled is brought to a halt.

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  • silvia
    What do fuel tubes from the space shuttle look like?
    2 months ago

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