Today, we learn how government secrecy sabotaged an
early satellite. The University of Houston's
College of Engineering presents this series about
the machines that make our civilization run, and
the people whose ingenuity created them.
Peter Likins, the President
of Lehigh University, tells an intriguing tale
about the first satellites. The first three
satellites launched were the Russian Sputniks I and
II, in October and November 1957, and the American
Explorer I in January 1958.
Explorer I was long and narrow like a pencil. It
was supposed to rotate around its own centerline,
like a pencil spinning about an axis along its lead
-- spinning with the least inertia. It was
definitely not supposed to rotate about an axis
perpendicular to its centerline, with its ends
describing circles -- in the maximum inertia mode.
The radio astronomer Ronald Bracewell at Stanford
University tracked the first Sputnik and determined
that it was spinning in its maximum inertia mode.
He knew about the dynamics of bodies that spin and
consume a little of their own spin energy while
they do, because that's how galaxies behave. What
Bracewell knew, and what the Explorer engineers
didn't know, was that the minimum inertia rotation
of Explorer I would be unstable -- that it would
soon flip over and start windmilling through space.
So Bracewell called the engineers at the Jet
Propulsion Laboratory to warn them. But people in
charge of secrecy wouldn't let him talk with the
engineers. He had to get the word out by publishing
a paper in the open literature. It came out seven
months after Explorer I was launched -- seven
months after Explorer I made just one earth orbit
and then flipped over to windmill from then on.
Actually, in 1957, another engineer named Landon
described that kind of instability in laboratory
notes at RCA. But he didn't publish them, nor was
he aware of the Explorer problem. Information that
isn't made public can't do anyone much good.
There can, I suppose, be good reasons for secrecy
in technology; but make no mistake, secrecy is an
enemy of progress. Creativity, freedom, and
openness are natural bedfellows.
A Russian engineer recently pointed out why the
United States stays ahead of Russia in computer
development. Once we established a lead, he says,
Russia tried to keep up by copying what we'd
already done. They have plenty of ways to break
through our security. But, being forced by their
system to play that game, instead being allowed to
trust their own inventive genius, they're trapped
in a technology that's doomed to stay one step
behind us.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
Likens, P., Spacecraft Attitude Dynamics and
Control-- A Personal Perspective on Early
Developments. Invited Lecture preprint, American
Institute of Aeronautics and Astronautics, 1985.
Bracewell, R. N., and Garriot, O. K., Rotation of
Artificial Earth Satellites. Nature, Vol.
182, Sept. 20, 1958, pp. 760 et seq.
This Episode has been revised as Episode 1332. I am grateful to
James Casey, University of California at Berkeley,
for suggesting this topic, and for considerable
counsel on the subject.
This episode is one of two that Vladimir Shtern
rendered into Russian in response to astronaut
Andrew Thomas's request that we send a set of
Engines episodes up to the Mir Space Station. (The
other one was Episode 1284.) For the text in Russian,
click on:
Page 1 of Russian
Text
Page 2 of Russian Text
The Engines of Our Ingenuity is
Copyright © 1988-1997 by John H.
Lienhard.
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