Showing posts with label exploration of space. Show all posts
Showing posts with label exploration of space. Show all posts

Monday, September 24, 2012

Rocket





The invention: Liquid-fueled rockets developed by Robert H. Goddard

made possible all later developments in modern rocketry,

which in turn has made the exploration of space practical.

The person behind the invention:



Robert H. Goddard (1882-1945), an American physics professor







History in a Cabbage Patch



Just as the age of air travel began on an out-of-the-way shoreline
at Kitty Hawk, North Carolina, with the Wright brothers’ airplane
in 1903, so too the seemingly impossible dream of spaceflight
began in a cabbage patch in Auburn, Massachusetts, with
Robert H. Goddard’s launch of a liquid-fueled rocket on March 16,
1926. On that clear, cold day, with snow still on the ground, Goddard
launched a three-meter-long rocket using liquid oxygen and
gasoline. The flight lasted only about two and one-half seconds,
during which the rocket rose 12 meters and landed about 56 meters
away.
Although the launch was successful, the rocket’s design was
clumsy. At first, Goddard had thought that a rocket would be
steadier if the motor and nozzles were ahead of the fuel tanks,
rather like a horse and buggy. After this first launch, it was clear
that the motor needed to be placed at the rear of the rocket. Although
Goddard had spent several years working on different
pumps to control the flow of fuel to the motor, the first rocket had
no pumps or electrical system. Henry Sacks, a Clark University
machinist, launched the rocket by turning a valve, placing an alcohol
stove beneath the motor, and dashing for safety. Goddard and
his coworker Percy Roope watched the launch from behind an iron
wall.
Despite its humble setting, this simple event changed the course
of history. Many people saw in Goddard’s launch the possibilities
for high-altitude research, space travel, and modern weaponry. Although
Goddard invented and experimented mostly in private,

others in the United States, the Soviet Union, and Germany quickly
followed in his footsteps. The V-2 rockets used by Nazi Germany
in World War II (1939-1945) included many of Goddard’s designs
and ideas.



A Lifelong Interest


Goddard’s success was no accident. He had first become interested
in rockets and space travel when he was seventeen, no doubt
because of reading books such as H. G.Wells’s The War of the Worlds
(1898) and Garrett P. Serviss’s Edison’s Conquest of Mars (1898). In
1907, he sent to several scientific journals a paper describing his ideas
about traveling through a near vacuum. Although the essay was rejected,
Goddard began thinking about liquid fuels in 1909. After finishing
his doctorate in physics at Clark University and postdoctoral
studies at Princeton University, he began to experiment.
One of the things that made Goddard so successful was his ability
to combine things he had learned from chemistry, physics, and
engineering into rocket design. More than anyone else at the time,
Goddard had the ability to combine ideas with practice.
Goddard was convinced that the key for moving about in space
was the English physicist and mathematician Sir Isaac Newton’s
third law of motion (for every action there is an equal and opposite
reaction). To prove this, he showed that a gun recoiled when it was
fired in a vacuum. During World War I (1914-1918), Goddard
moved to the Mount Wilson Observatory in California, where he
investigated the use of black powder and smokeless powder as
rocket fuel. Goddard’s work led to the invention of the bazooka, a
weapon that was much used duringWorldWar II, as well as bombardment
and antiaircraft rockets.
After World War I, Goddard returned to Clark University. By
1920, mostly because of the experiments he had done during the
war, he had decided that a liquid-fuel motor, with its smooth thrust,
had the best chance of boosting a rocket into space. The most powerful
fuel was hydrogen, but it is very difficult to handle. Oxygen had
many advantages, but it was hard to find and extremely dangerous,
since it boils at -148 degrees Celsius and explodes when it comes in
contact with oils, greases, and flames. Other possible fuels were pro-

pane, ether, kerosene, or gasoline, but they all had serious disadvantages.
Finally, Goddard found a local source of oxygen and was able
to begin testing its thrust.

Another problem was designing a fuel pump. Goddard and his
assistant Nils Riffolt spent years on this problem before the historic
test flight of March, 1926. In the end, because of pressure from the
Smithsonian Institution and others who were funding his research,
Goddard decided to do without a pump and use an inert gas to
push the fuel into the explosion chamber.
Goddard worked without much funding between 1920 and 1925.
Riffolt helped him greatly in designing a pump, and Goddard’s
wife, Esther, photographed some of the tests and helped in other
ways. Clark University had granted him some research money in
1923, but by 1925 money was in short supply, and the Smithsonian
Institution did not seem willing to grant more. Goddard was convinced
that his research would be taken seriously if he could show
some serious results, so on March 16, 1926, he launched a rocket
even though his design was not yet perfect. The success of that
launch not only changed his career but also set the stage for rocketry
experiments both in the United States and in Europe.



Impact


Goddard was described as being secretive and a loner. He never
tried to cash in on his invention but continued his research during
the next three years. On July 17, 1929, Goddard launched a rocket
carrying a camera and instruments for measuring temperature
and air pressure. The New York Times published a story about the
noisy crash of this rocket and local officials’ concerns about public
safety. The article also mentioned Goddard’s idea that a similar
rocket might someday strike the Moon. When American aviation
hero Charles A. Lindbergh learned of Goddard’s work, Lindbergh
helped him to get grants from the Carnegie Institution and the
Guggenheim Foundation.
By the middle of 1930, Goddard and a small group of assistants
had established a full-time research program near Roswell, New
Mexico. Now that money was not so much of a problem, Goddard
began to make significant advances in almost every area of astronautics.
In 1941, Goddard launched a rocket to a height of 2,700 meters.
Flight stability was helped by a gyroscope, and he was finally
able to use a fuel pump.

 During the 1920’s and 1930’s, members of the American Rocket
Society and the German Society for Space Travel continued their
own research. When World War II began, rocket research became a
high priority for the American and German governments.
Germany’s success with the V-2 rocket was a direct result of
Goddard’s research and inventions, but the United States did not
benefit fully from Goddard’s work until after his death. Nevertheless,
Goddard remains modern rocketry’s foremost pioneer—a scientist
with vision, understanding, and practical skill.



                                                                 







                                                                       Robert H. Goddard









In 1920 The New York Times made fun of Robert Hutchings
Goddard (1882-1945) for claiming that rockets could travel
through outer space to the Moon. It was impossible, the newspaper’s
editorial writer confidently asserted, because in outer
space the engine would have no air to push against and so
could not move the rocket. A sensitive, quiet man, the Clark
University physics professor was stung by the public rebuke,
all the more so because it displayed ignorance of
basic physics. “Every vision is a joke,” Goddard
said, somewhat bitterly, “until the first man accomplishes
it.”
Goddard had already proved that a rocket could
move in a vacuum, but he refrained from rebutting
the Times article. In 1919 he had become the first
American to describe mathematically the theory of
rocket propulsion in his classic article “A Method of
Reaching Extreme Altitude,” and duringWorldWar I
he had acquired experience designing solid-fuel rockets.
However, even though he was the world’s leading
expert on rocketry, he decided to seek privacy for
his experiments. His successful launch of a liquidfuel
rocket in 1926, followed by new designs that reached ever
higher altitudes, was a source of satisfaction, as were his 214
patents, but real recognition of his achievements did not come
his way untilWorldWar II. In 1942 he was named director of research
at the U.S. Navy’s Bureau of Aeronautics, for which he
worked on jet-assisted takeoff rockets and variable-thrust liquid-
propellant rockets. In 1943 the Curtiss-Wright Corporation
hired him as a consulting engineer, and in 1945 he became director
of the American Rocket Society.
The New York Times finally apologized to Goddard for its
1920 article on the morning after Apollo 11 took off for the
Moon in 1969. However, Goddard, who battled tuberculosis
most of his life, had died twenty-four years earlier.



See also here !