On the bright, cold morning of March 16, 1926, Robert H. Goddard, a 44-year-old physics professor,
tramped out into a snow-covered cabbage field outside Auburn, Massachusetts and began setting
up a strange assembly of aluminium hoses and tanks.
At 2:30 that afternoon the contraption was ready, and with his wife and a handful of
bystanders looking on, Goddard backed away to a safe distance and pulled on a long rope.
An ear-splitting screech filled the air as a tongue of flame a foot long shot out of
the device.
At first it clung stubbornly to the ground, but a few seconds later it suddenly shot up
and roared into the air, tracing a tall arc across the sky before streaking down and impacting
the ground 200 feet away.
In that moment, the world changed forever.
Though Goddard’s device had risen only 41 feet, that short flight was the first successful
demonstration of a liquid-fuelled rocket - an event as important to space exploration as
the Wright Brothers’ first flight in 1903 is to aviation.
Every rocket built since, up to the mighty Saturn V that sent men to the moon, owes much
of its design to Goddard’s pioneering work.
Yet despite its historic status, Goddard’s 1926 rocket looks nothing like any rocket
built before or since, being built upside down with its combustion chamber and nozzle
at the top and propellant tanks at the bottom.
But why on earth would Goddard build a rocket in this counterintuitive manner?
The reason has to do with a once-common misunderstanding of physics known as the Pendulum Rocket Fallacy.
Robert Hutchings Goddard’s lifelong obsession with rocketry and spaceflight can be traced
to a single time and place.
On October 19, 1899, the 17-year old Goddard was visiting relatives outside his hometown
of Worcester, Massachusetts when he climbed a cherry tree to trim some dead limbs.
On reaching the top, he looked up into the endless sky and suddenly found himself overcome
by an overwhelming sense of awe and wonder.
As he later wrote:
“As I looked toward the fields at the east, I imagined how wonderful it would be to make
some device which had even the possibility of ascending to Mars, and how it would look
on a small scale, if sent up from the meadow at my feet.
I have several photographs of the tree, taken since, with the little ladder I made to climb
it, leaning against it.
It seemed to me then that a weight whirling around a horizontal shaft, moving more rapidly
above than below, could furnish lift by virtue of the greater centrifugal force at the top
of the path.
I was a different boy when I descended the tree from when I ascended.
Existence at last seemed very purposive.”
For the rest of his life Goddard would celebrate October 19 as his “Anniversary Day”.
Goddard completed his graduate studies at Clark University, receiving his Masters in
Physics in 1910 and his PhD in 1911.
He soon secured a research fellowship at Princeton University’s Palmer Physical Laboratory,
where he began his private studies on rocketry and space travel.
He submitted his first paper on the subject, The Navigation of Space, to the magazine Popular
Science News, but it was returned with a note claiming they had no plans to publish it in
the immediate future.
This was hardly surprising; in the late 19th and early 20th Centuries most scientists saw
rockets little more than toys, dismissing them as a viable means of reaching space or
as a respectable field of study for a physicist.
Indeed, even contemporary science fiction featuring space travel made little use of
rockets, preferring other methods such as giant cannons, antigravity, and even astral
projection.
But Goddard was undeterred, and continued his studies in his spare time.
In 1912 Goddard proved mathematically that a rocket fuelled by liquid propellant rather
than gunpowder could theoretically reach any altitude and place substantial payloads into
outer space.
Goddard had in fact inadvertently re-derived the prior work of Russian theorist Konstantin
Tsiolkovsky, who in 1903 published the groundbreaking treatise The Exploration of Space by Means
of Reactive Propelled Devices.
The paper, considered the founding document of modern astronautic theory, outlined many
concepts fundamental to modern space travel, such as rocket staging and the Tsiolkovsky
Rocket Equation for calculating the amount of propellant needed to reach a certain altitude.
However, due to his reclusive nature and his inability to widely distribute his papers,
Tsiolkovsky’s work remained all but unknown in the West during his lifetime.
Goddard nearly became a footnote in history himself when in 1913 he came down with severe
bout of Tuberculosis and was forced to abandon his research post.
Though he came very close to death, he eventually recovered and in 1914 accepted a part-time
teaching position at Clark University.
Here he transitioned from purely theoretical work to practical experimentation, building
a series of gunpowder-fuelled rocket motors with which to test various nozzle designs.
These motors achieved internal efficiencies as high as 63%, validating Goddard’s belief
that rockets could be an efficient form of aerial propulsion.
But Goddard’s research soon became too expensive for his meagre salary of $1000/year to sustain,
and he reached out to groups such as the National Geographic Society and the Smithsonian Institution
for financial assistance.
To his delight, in January 1917 the Smithsonian agreed to provide him with a five-year grant
totalling $5000.
Clark University later contributed $3500 while the Worcester Polytechnic Institute provided
space in its abandoned magnetics laboratory for Goddard to safely test his motors.
In 1919, after two years of research, Goddard arranged for the Smithsonian to publish what
would become his magnum opus, A Method of Reaching Extreme Altitudes.
In addition to his theoretical calculations on rocket performance and the results of his
experiments on nozzle efficiencies, the paper included a memorable thought experiment in
which Goddard proposed launching a rocket to the moon and igniting a charge of flash
powder on its surface, the light from which would be just visible from the earth.
But while this section constituted only a small fraction of the entire paper, reporters
immediately focused in on it, leading to Goddard being widely mocked in the press.
On January 12, 1920, the New York Times ran a scathing front-page story titled “Believes
Rocket Can Reach Moon,” while the next day an unsigned editorial titled “A Severe Strain
on Credulity” further ridicule Goddard’s conclusions.
Other papers followed suit; following a 1929 rocket flight, a local Worcester newspaper
carried the headline “Moon rocket misses target by 238,799 1⁄2 miles.”
Even Goddard’s colleagues joined in, with one professor asking him “Well, Robert,
how is your moon-going rocket?”
Despite numerous attempts to set the record straight, Goddard was unable to quell the
press’s mockery.
In a 1920 interview he resignedly stated:
“Every vision is a joke until the first man accomplishes it.
Once realized, it becomes commonplace.”
The overwhelmingly negative reaction to his paper changed Goddard forever.
Already a shy and retiring man, over the next two decades he would become increasingly secretive
and protective of his work for fear of attracting the same mockery.
The lingering effects of his tuberculosis also contributed to his isolation, as he preferred
to avoid exhausting arguments with others and use his energy productively.
Unfortunately, this behaviour would ultimately result in Goddard and his work falling into
obscurity.
In September 1921 Goddard began experimenting with liquid propellant rockets, successfully
testing his first prototype engine in November 1923.
After trying out a number of different propellants, Goddard settled on the combination of gasoline
and liquid oxygen.
During static testing he encountered a problem that has plagued rocket designers ever since:
at the ideal propellant mixture ratio the exhaust was so hot that it quickly burned
through the thin walls of the engine nozzle.
Goddard solved this problem by running his engine intentionally fuel-rich to reduce the
exhaust temperature - an inefficient solution, but the only practical one given Goddard’s
limited resources.
The second challenge Goddard faced in building a practical rocket was how to keep it stable
in flight, and to this end he opted to build his pioneering 1926 rocket in an usual upside-down
configuration, with the combustion chamber at the top and the propellant tanks at the
bottom - the two being connected by the rigid propellant feed lines.
The idea was that the low centre of gravity would cause the rocket to act like a pendulum
and keep it pointing upward.
But while at first glance this solution seems to make intuitive sense, a closer look at
the physics reveals it to be a fallacy.
Flying a rocket can be thought of like balancing a pencil on your fingertip; some mechanism
is needed to constantly counteract the rocket’s tendency to topple over and keep it on its
desired trajectory.
In smaller, simpler rockets this is accomplished using fins, which apply an aerodynamic counterforce
to keep the vehicle flying in a straight line.
Larger rockets - especially those that must operate in the vacuum of space - use a set
of gyroscopes and gimbaling nozzles to redirect the rocket exhaust and keep themselves on
course.
But in the early days of rocketry, many scientists and engineers - including Goddard - believed
that if a rocket was built like a pendulum - with the nozzle on top and the majority
of the weight at the bottom - then like a pendulum the vehicle would stabilize itself
and always point straight upwards.
While this seems intuitive on its face, a closer examination of the physics reveals
that this concept is deeply flawed.
For a system to be stable, there must exist a suitable counter-force to counteract any
deviations from its ground state.
Take, for example, a marble at the bottom of a bowl.
This system is stable because any attempt to disturb the marble is counteracted by gravity,
which always returns it to the bottom of the bowl.
If, on the other hand, the bowl is flipped over and the marble placed on top, the system
becomes inherently unstable as any disturbance will send the marble rolling down the sides,
with no counter-force to stop it.
A rocket in flight is a similarly unstable system, like a pencil balanced on a fingertip;
some mechanism or counterforce is thus needed to counter its tendency to topple over.
In small rockets this is accomplished using fins, which apply aerodynamic forces to keep
the vehicle on-course.
Larger rockets - especially those which must also operate in the vacuum of space - use
gimballed nozzles to deflect the rocket exhaust and counteract any deviations in trajectory.
If, on the other hand, Goddard’s pendulum rocket were disturbed from its flight path
by even a few degrees, the line of thrust would still point along the length of the
rocket just as it did when the rocket was vertical, with nothing providing a counter-force
to correct the deviation.
Furthermore, unlike a pendulum which is hinged at the top, the combustion chamber on Goddard’s
rocket was rigidly connected to the propellant tanks, meaning that once the combustion chamber
went off-course, the whole rocket would go with it.
For the pendulum effect to work at all, heavy objects would have to fall faster than light
ones - a notion disproved by Galileo way back in 1592.
Thus Goddard’s pendulum rocket was in fact no more stable than a more conventional design,
and indeed on its pioneering 1926 flight rose only a few feet before flipping uncontrollably
end-over-end and crashing.
Goddard quickly realized his mistake and built all his subsequent rockets in the more traditional
style with the engine on the bottom - a far more convenient configuration which eliminated
the need to shield the highly-combustible propellant tanks from the rocket’s exhaust.
The pendulum rocket fallacy thus represents a brief and curious dead-end in the history
of rocketry, and proof that even the greatest minds can get it wrong sometimes.
But this was not the first baffling scientific blunder Goddard had been involved in, though
in the prior case he had been on the correct side of the debate.
One of the harshest criticisms levelled against Goddard regarding his 1919 paper involved
his assertion that rocket engine could work in the vacuum of space.
Early on Goddard had realized that rockets worked according to Newton’s Third Law - that
is, for every action there is an equal and opposite reaction - and that the presence
of an atmosphere was irrelevant to their operation.
He had even proven this experimentally by measuring the thrust of small rocket motors
in a vacuum chamber, discovering that the performance of rockets actually increases
as the surrounding pressure decreases.
But conventional scientific wisdom held that rockets worked by pushing against the atmosphere,
as the author of the 1920 New York Times editorial scathingly explained:
“After the rocket quits our air and really starts on its longer journey, its flight would
be neither accelerated nor maintained by the explosion of the charges it then might have
left.
To claim that it would be is to deny a fundamental law of dynamics, and only Dr. Einstein and
his chosen dozen, so few and fit, are licensed to do that.
Professor Goddard, with his ‘chair' in Clark College…does not know the relation of action
to reaction, and of the need to have something better than a vacuum against which to react.
[He] seems to lack the knowledge ladled out daily in high schools.”
Once again Goddard published numerous rebuttals defending his scientific statements, but to
no avail.
It was not until 49 years later, shortly after the launch of Apollo 11, that the Times finally
printed a formal retraction:
“Further investigation and experimentation have confirmed the findings of Isaac Newton
in the 17th Century and it is now definitely established that a rocket can function in
a vacuum as well as in an atmosphere.
The Times regrets the error.”
Following his historic 1926 launch Goddard continued to build and launch increasingly
successful rockets near Auburn, but once again these activities soon outstripped his meagre
funds.
Fortuitously, however, his research had come to the attention of a figure of great influence
in the aerospace community: Charles Lindbergh, the first man to fly solo nonstop across the
Atlantic.
In the spring of 1930, Lindbergh met with the wealthy Guggenheim family and convinced
them to fund Goddard’s research over the next four years to the tune of $100,000 - $1.9
million today.
He also found Goddard an ideal test site near Roswell in the New Mexico desert, which was
not only wide-open, secluded, and sparsely populated, but also had a dry climate better
suited to Goddard’s tubercular lungs.
Over the next 11 years Goddard and a small group of technicians would work in near-complete
isolation and secrecy, launching a total of 31 rockets into the desert sky.
In the process they pioneered many now- common technologies like gyroscopic stabilization
and thrust vectoring and launched the first rocket-borne scientific instruments - a barometer
and thermometer - creating the world’s first meteorological sounding rocket.
Yet despite these firsts the performance of Goddard’s rockets was disappointing, his
most successful model, launched on March 26, 1937, only reaching a maximum altitude of
2.5 kilometres.
Much of this lack of progress stemmed from Goddard’s obsession with solitude and secrecy,
which prevented him from communicating with other scientists and avoiding problems which
had already been solved elsewhere.
Nonetheless, the Navy was impressed by his work and during the Second World War he moved
to Annapolis, Maryland to develop Jet-Assisted-Takeoff or JATO rockets to help heavily-laden aircraft
get off the ground.
But this would be Goddard’s last hurrah.
His health already deteriorating due to the humid Maryland climate, in mid-1945 he was
diagnosed with throat cancer.
On August 10, Robert Hutchings Goddard died in Baltimore at the age of 63.
Yet despite all his achievements, at the time of his death Goddard and his work were all
but unknown in America, and he soon slipped into obscurity.
But halfway around the world there were people who had heard of Robert Goddard.
In 1920, Goddard personally sent out 1750 copies of his pioneering monograph to anyone
who requested one.
A handful of these ended up in Germany, where they inspired a generation of rocket enthusiasts
- including a young Werner von Braun.
Working from Goddard’s ideas and research, in the late 1930s von Braun and his team at
the Air Force research station at Peenemunde designed a series of increasingly-sophisticated
liquid-fuelled rockets, culminating in the infamous V2 ballistic missile - one of Hitler’s
so-called “vengeance weapons” of which thousands were launched against Britain during
the Second World War.
After the war, von Braun and many of his colleagues were brought to the United States via Operation
Paperclip to assist in the U.S. Army’s missile programs.
On arriving in America, von Braun was shocked to learn that nobody had heard of Robert Goddard
or his pioneering work, exclaiming:
“Don't you know about your own rocket pioneer?
Dr. Goddard was ahead of us all.”
As the Space Race between the United States and Soviet Union got underway in the late
1950s, Goddard and his achievements were increasingly recognized and celebrated, with the Goddard
Spaceflight Centre in Greenbelt, Maryland being named in his honour in 1959.
Today he is widely recognized as the Father of American Rocketry, and an important pioneer
in the history of spaceflight.
But while Goddard saw little success and recognition in his lifetime, this seems to have done little
to discourage him or his dreams of reaching the stars.
Writing to science fiction novelist H.G. Wells in 1932, Goddard mused:
“How many more years I shall be able to work on the problem, I do not know; I hope,
as long as I live.
There can be no thought of finishing, for "aiming at the stars", both literally and
figuratively, is a problem to occupy generations, so that no matter how much progress one makes,
there is always the thrill of just beginning.”