"Theory of Diffraction"

by Robert Hutchings Goddard


Theory of Diffraction

by Robert Hutchings Goddard

A Thesis Presented to the Faculty of Clark University, in Partial Fulfillment of the Requirements for the Degree of Master of Arts, June 8, 1910

Robert Hutchings Goddard is widely regarded as "the father of modern rocketry."  Born a the son of a machine shop owner in 1882, Goddard became a physics instructor at Clark University.  In 1910 he submitted this hand-written thesis, to receive this Master of Arts (MA) degree.

An important (and hard-to-find) document, "Theory of Diffraction" covers light, shadows, the Fraunhofer diffraction phenomena, Babinet's principle, apertures of various sizes and shapes, screens, diffraction gratings, Fresnel diffraction phenomena, Summerfeld's Treatment, and applications to a perfectly reflecting body.  Written in his own hand, with many detailed (and hand-drawn) illustrations, this book is a most interesting read for everyone interested in the science of light.

The book also provides many insights into the mind and thinking of this important inventor.  It's a good (an most unusual) addition to the collection of any rocket scientist, engineer, or technician, as well.

As a young physics graduate student, he conducted static tests with small solid-fuel rockets, and in 1912 he developed the detailed mathematical theory of rocket propulsion.  He continued these efforts and actually received two patents in 1914.  One was the first for a rocket using solid and liquid fuel, and the other for a multistage rocket. 

In 1915 he proved that rocket engines could produce thrust in a vacuum--proving that space flight was indeed possible.  In 1916 the Smithsonian Institution provided funds for Goddard to continue his work on solid-propellant rockets and to begin development of liquid-fuel rockets as well.

During World War I, Goddard developed several types of solid-fuel rockets to be fired from handheld launching tubes.  These formed the basis of the bazooka and other powerful rocket weapons of World War II.

Goddard continued as a professor of physics at Clark, turning his attention to liquid rocket propulsion.  In 1916 he applied to the Smithsonian Institution for assistance in 1916 and received a $5,000 grant.  His research was ultimately published by the Smithsonian as the classic study, A Method of Reaching Extreme Altitudes, in 1919.

In this now-famous treatise, Goddard described how rockets could be used to explore the upper atmosphere.  He went on to show that at a velocity of 6.95 miles per second (11.2 kps), without air resistance, an object could escape Earth's gravity and head into infinity, or toward other celestial bodies. This became known as the Earth's "escape velocity."  He explained that humans could reach the Moon using these techniques.

On March 16, 1926, Goddard launched his first liquid-fuel rocket, a liquid oxygen and gasoline vehicle that rose 184 feet in 2.5 seconds.  This event heralded the modern age of rocketry.

He continued to experiment with rockets and propellants for the rest of his life.  From 1930 to 1941, he launched rockets of increasing complexity and capability.  He developed systems for steering a rocket in flight by using a rudder-like device to deflect the gaseous exhaust, with gyroscopes to keep the rocket headed in the proper direction. 

The culmination of this effort was a successful launch of a rocket to an altitude of 9,000 feet in 1941.  Later that year joined the U.S. Navy, and spent the duration of World War II developing a jet-assisted takeoff (JATO) rocket to shorten the distance required for heavy aircraft launches.  Some of this work led to the development of the “throttlable” Curtiss-Wright XLR25-CW-1 rocket engine, which later powered the Bell X-2 research airplane and helped overcome the transonic barrier in 1947.  Goddard did not live to see this; he died in Baltimore, Maryland, on August 10, 1945.

In 1960 the U.S. government recognized Robert Goddard's work when the Department of Defense and the National Aeronautics and Space Administration (NASA) awarded his estate $1 million for the use of his 214 rocketry patents.  Although he did not live to see the space age begin, if any one man had a central role in its creation, it was Goddard.

Samples of Goddard's hand-drawn illustrations from the text
(much smaller than in book)

We obtained a high-resolution digital scan of Robert H. Goddard's original manuscript, and have printed it with a high-resolution laser printer (not photocopied) on high-quality, bright-white, 24-pound, acid-free paper.  It's quality bound for years of reference use.  70 pages, 8-1/2 x 5-1/2" size.


Priority Mail Postage US $3.85            Global Priority Mail (Canada / Mexico) US$7.00          Global Priority Mail International US$9.00.

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