The Man Who Started the Space Age

The Russian (Ukraine-born) rocket engineer Sergei Korolev (1907–66) was the driving technical force behind the initial intercontinental ballistic missile (ICBM) program and the early outer space exploration projects of the former Soviet Union. In 1954, he started work on the first Soviet ICBM, called the R-7. This powerful rocket system was capable of carrying a massive payload across continental distances. As part of cold-war politics, Soviet premier Nikita Khrushchev allowed Korolev to use this military rocket to place the first artificial satellite (named Sputnik 1) into orbit around Earth on October 4, 1957. This event is now generally regarded as the beginning of the Space Age. Korolev was also the technical expert responsible for the April 12, 1961, mission that placed the first human (Yuri Gagarin) in orbit around Earth in the Vostok 1 spacecraft.

Korolev was trained in aeronautical engineering at the Kiev Polytechnic Institute and, after receiving a secondary education, cofounded the Moscow rocketry organization GIRD (Gruppa Isutcheniya Reaktivnovo Dvisheniya, Group for Investigation of Reactive Motion). In Russia, GIRD lasted only two years before the military, seeing the potential of rockets, replaced it with the RNII (Reaction Propulsion Scientific Research Institute). RNII developed a series of rocket-propelled missiles and gliders during the 1930s, culminating in Korolev’s RP-318, Russia’s first rocket propelled aircraft. Before the aircraft could make a rocket-propelled flight, however, Korolev and other aerospace engineers were thrown into the Soviet prison system in 1937–38, during the peak of Joseph Stalin’s political purges.

Korolev at first spent months in transit on the Trans-Siberian railway and on a prison vessel at Magadan. This was followed by a year in the Kolyma gold mines, the most dreaded part of the Gulag. However, Stalin recognized the importance of aeronautical engineers in preparing for the impending war with Hitler and retrieved Korolev and other technical personnel from incarceration. He reasoned that these prisoners could help the Red Army by developing new weapons. Consequently, a system of sharashkas (prison design bureaus) was set up to exploit the jailed talent.

Korolev was saved by the intervention of senior aircraft designer Sergei Tupolev, himself a prisoner, who personally requested Korolev’s services in the TsKB-39 sharashka.

Following World War II, Korolev was released from prison and appointed chief constructor for development of a long-range ballistic missile. By April 1, 1953, as Korolev was preparing for the first launch of the R-11 rocket, he received approval from the Council of Ministers for development of the world’s first ICBM, the R-7. To concentrate on development of the R-7, Korolev’s other projects were spun off to a new design bureau in Dnipropetrovs’k headed by Korolev’s assistant, Mikhail Kuzmich Yangel.

This was the first of several design bureaus that would spin off from Korolev’s work. It was Korolev’s R-7 ICBM that launched Sputnik 1 on October 4, 1957. During the early 1960s, Korolev campaigned to send a Soviet cosmonaut to the Moon. Following the initial reconnaissance of the Moon by the Luna 1, 2, and 3 spacecraft, Korolev established three largely independent efforts aimed at achieving a Soviet lunar landing before the Americans. The first objective, met by Vostok and Voskhod spacecraft, was to prove that human spaceflight was possible. The second objective was to develop lunar vehicles, which would soft-land on the Moon’s surface to ensure that a cosmonaut would not sink into the dust accumulated by 4 billion years of meteorite impacts. The third objective, and the most difficult to achieve, was to develop a huge booster to send cosmonauts to the Moon. Beginning in 1962, his design bureau began work on the N-1 launch vehicle, a counterpart to the American Saturn V. This giant rocket was to be capable of launching a maximum of 110,000 pounds (50,000 kg) into low-Earth orbit. Although the project continued until 1971 before cancellation, the N-1 never made a successful flight.

On January 14, 1966, Korolev died at a hospital in Moscow. He was only 58 years old. Some of Korolev’s contributions to space technology include the powerful, legendary R-7 rocket (1956); the first artificial satellite (1957); pioneering lunar spacecraft missions (1959); the first human spaceflight (1961); a spacecraft to Mars (1962); and the first space walk (1965). Korolev is now recognized as the brilliant rocket engineer who ushered in the Space Age.

Text 4 Andrey Nikolayevich Tupolev

Andrey Nikolayevich Tupolev,  (born October 29 [November 10, New Style], 1888, Pustomazovo, Russia—died December 23, 1972, Moscow), one of the Soviet Union’s foremost aircraft designers, whose bureau produced a number of military bombers and civilian airliners—including the world’s first supersonic passenger plane.

In 1909 Tupolev entered the Moscow Imperial Technical School (now Bauman Moscow State Technical University), where he became a student and disciple of Nikolay Y. Zhukovsky, widely considered the father of Russian aviation. In 1918 they organized the Central Aerohydrodynamics Institute, of which Tupolev became assistant director in 1918. He became head of the institute’s design bureau in 1922 and supervised the work of various designers—including Pavel O. Sukhoy, Vladimir M. Myasischev, and Vladimir M. Petlyakov—who later became notable in their own right. This bureau, in producing military and civilian planes that were designated by Tupolev’s initials, ANT, made all-metal construction a standard feature of Soviet aviation.

In 1937 Tupolev, in common with many Soviet designers at the time, was arrested on charges of activities against the state. Following his imprisonment, he was placed in charge of a team that was to design military aircraft. From this came the Tu-2, a twin-engine bomber that saw wide use in World War II and, in 1943, earned Tupolev his freedom and a Stalin Prize. Near the end of the war he was given the job of copying the U.S. B-29 Superfortress, three of which had force-landed in the Soviet Far East. This project resulted in the Tu-4 (NATO designation “Bull”), which first flew in 1947 and was the U.S.S.R.’s principal strategic bomber until the mid-1950s.

After adapting jet propulsion to several piston-engine airframes, Tupolev in 1952 introduced the Tu-16 (“Badger”), a medium-range bomber that featured swept wings and light alloy construction. A team under Aleksandr A. Arkhangelsky, Tupolev’s longtime associate, designed the Tu-95 (“Bear”), a huge turboprop bomber that first flew in 1954 and became one of the most durable military aircraft ever built. Two civilian aircraft were derived from these—the Tu-104, which appeared in 1955 and became one of the first jet transports to provide regular passenger service, and the Tu-114 long-range passenger plane, the largest propeller-driven aircraft ever in regular service.

In 1963 Tupolev’s son Alexey became chief designer of a team that produced the Tu-144 supersonic transport. The Tu-144 broke the sound barrier—the first passenger plane to do so—on a test flight in 1969 and reached twice the speed of sound a year later, but it was plagued by design problems and mismanagement and had only a short life as a passenger jet in 1977–78.

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How do aeronautical engineers study aircraft and design new ones?

As the use of the scientific method became increasingly important, it also became clear to aircraft designers that testing their hypotheses with human subjects was too risky. Wind tunnels were the first tool of aeronautics to be developed. In the very early 1900s designers built models of their aircraft and placed them in tunnels through which air could be blown to simulate flight. While wind tunnels did provide valuable information and were certainly safer than human flight, there were many questions that were left unsolved simply because the interactions of all the forces on an aircraft were too complex for the analysis methods of the day.

The advent of the computer changed everything. Now massive quantities of data could be gathered from wind tunnel tests and analyzed quickly and efficiently using the computer. In addition, new tools were developed.

Next came flight simulators which enabled a pilot to fly without ever leaving the ground. Flight simulator cockpits were designed to be exact duplicates of real aircraft cockpits. Motion systems were added and have evolved to the point where it is very hard to tell the difference between an airplane ride and a simulator ride.

As computers became more sophisticated, they became able to handle vast amounts of data. Aeronautical researchers began simulating airflow in a computer. Computational Fluid Dynamics was born. As advances in computer graphics have been made, it is now possible to sit at a desk and watch a computer-generated airplane fly - complete with the ability to visualize airflow and pressures as well as fly the airplane from takeoff to landing.

However, even with our increased ability to use computers, simulators and wind tunnels, the final and most definitive test of an aircraft is whether or not a pilot can fly it. Flight test, in which a human climbs into the cockpit and flies the aircraft, was originally the first tool of aeronautics but now remains the final and most important test that an aircraft must undergo. Vast improvements have been made in the safety of flight test and the ability of ground engineers and pilots to predict and avoid hazardous situations. All the tests using the other tools of aeronautics result in an aircraft being far more flight-worthy by the time it reaches flight test than it has in the past.

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Microwaves for Radar

World War II provided the impetus to harness microwave energy as a means of detecting enemy planes. Early radars were mounted on the Cliffs of Dover to bounce their microwave signals off Nazi bombers that threatened England. The word radar itself is an acronym for RAdio Detection And Ranging.

Radars grew more sophisticated. Special-purpose systems were developed to detect airplanes, to scan the horizon for enemy ships, to paint finely detailed electronic pictures of harbors to guide ships, and to measure the speeds of targets.

These were installed on land and aboard warships. Radar—especially shipboard scales toward an Allied victory in World War II.

Today, few mariners can recall what it was like before radar. It is such an important aid that it was embraced universally as soon as hostilities ended. Now, virtually every commercial vessel in the world has one, and most larger vessels have two radars: one for use on the open sea and one, operating at a higher frequency, to “paint” a more finely detailed picture, for use near shore.

Microwaves are beamed across the skies to fix the positions of aircraft in flight, an essential aid to control the movement of aircraft from city to city across the nation. These radars have also been linked to computers to tell air traffic controllers the altitude of planes in the area and to label them on their screens.

A new kind of radar, phased array, is now being used to search the skies thousands of miles out over the Atlantic and Pacific oceans. Although these advanced radars use microwave energy just as ordinary radars do, they do not depend upon a rotating antenna. Instead, a fixed antenna array, comprising thousands of elements like those of a fly’s eye, looks everywhere. It has been said that these radars roll their eyes instead of turning their heads

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Weight

Weight, or gravity, is the force which always acts downward, toward the center of the earth. It is the total sum of the masses of all its components and contents multiplied by the strength of the gravity, commonly referred to as the number of g’s. The weight may be considered to act as a single force, representing all its components and contents, through a single point called the center of gravity.

Weight is the most reliable force, which always acts in the same direction and gradually decreases as airplane fuel is used. The center of gravity shifts as the weight is redistributed. Although the terms “mass” and “weight” are often confused with each other, it is important to distinguish between them. Mass is a property of a body itself and measures a body’s quantity of matter. Weight, in contrast, is a force representing the force of gravity acting on a body. It is also loosely called gravity. To illustrate the difference, one could describe an object that is taken to the Moon, where the force of gravity is weaker, about one-sixth that on Earth. On the Moon, the object will weigh only about one-sixth as much as it did on Earth. The mass of the object will be the same on the Moon or anywhere else. In other words, it will continue to have the same amount of matter.

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Drag

When an object moves relative to a fluid, either a gas or a liquid, the fluid exerts a frictional force on the object. This force which is referred to as a drag force, is due to the viscosity, or stickiness, of the fluid and also, at high speeds, to the turbulence behind and around the object. To characterize the motion of an object at different speeds relative to the fluid and to understand the associated drag, it is useful to understand Reynolds numbers. The Reynolds number depends on the properties, such as length and velocity, of the fluid and the object relative to the fluid. In case of an airplane, which flies through air, the Reynolds number for air is smaller than that for water because of the lower density of the air. For example, an object of one millimeter long moving with a speed of 1 millimeter per second through water has the same Reynolds number as an object 2 millimeters long moving at a rate of 7 millimeters per second in the air. The drag manifests itself differently for different Reynolds numbers associated to it.

When the Reynolds number is less than 1, as in the case of fairly small objects, such as raindrops, the viscous force is directly proportional to the speed of the object. For large Reynolds numbers, usually above a value between about 1 and 10, there will be turbulence behind the body, known as wake, and hence, the drag force will be larger and it increases as the square of the velocity instead of its linear dependence on the velocity. When the Reynolds number approaches a value of around 1,000,000, the drag force increases abruptly. For above this value, turbulence exits in the layer of fluid lying next to the body all along its sides.

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Lift

Airplane wings and other airfoils are designed to deflect the air so that, although streamline flow is largely maintained, the streamlines are crowded together above the wing. Just as the flow lines are crowded together in a pipe constriction where the velocity is high, so the crowded streamlines above the wing indicate that the airspeed is greater than below the wing. Hence, according to Bernoulli’s principle which states that velocity increases as pressure decreases, the air pressure above the wing is less than that below the wing, and there is a net upward force, which is called dynamic lift, or lift.

In fact, Bernoulli’s principle is only one aspect of the lift on a wing. Wings are usually tilted slightly upward so that air striking the bottom surface is deflected downward. The change in momentum, a product of mass and velocity, of the rebounding air molecules results in an additional upward force on the wing. As the air passes over the wing, it is bent down. The bending of the air is the action; the reaction is the lift on the wing. To generate sufficient lift, a wing must divert air down. To increase the lift, either or both the diverted air and downward velocity must be incremented.

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Thrust

A force pushing an airplane, or any object, forward is called thrust. The thrust is produced by the engines of the airplane or by the flapping of a bird’s wings. The engines push fast-moving air out behind the plane, by either propeller or jet. The fast-moving air causes the plane to move forward, countering drag. Since the Wright brothers first flew in 1903, aeronautical engineers have created a multitude of airplane types, every one of which has dealt with the same four forces of weight, drag, lift, and thrust. All people have to deal with the challenges of stability with respect to these forces. Flying faster than the speed of sound has its own special demands, but the underlying forces of weight, drag, lift, and thrust remain the same.

In some sense, it is easier to fly in space, which is devoid of air, than it is to fly in air. However, spaceflight has its own special challenges. In space, one must deal with only two forces, weight and thrust. Thrust provides the force to lift a rocket into space. Once in orbit, a spacecraft no longer needs propulsion. Short bursts from smaller rockets are used to maneuver the spacecraft. To change its orientation, a spacecraft applies torque, a twisting force, by firing small rockets called thrusters or by spinning internal reaction wheels.

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