The year
was 1966 and NASA was testing its first fully-assembled, 36-story tall Saturn V
moon rocket at its launch facilities in Florida. Despite the threat posed by a
hurricane and a ruptured fuel line, the trials with the sky-scraping booster
had gone well and it came time to separate the Saturn into its five stages in
the voluminous Vertical Assembly Building that had been erected for that very
purpose.
But NASA
engineers had another idea: though
the 363-foot (110-meter) tall rocket had been analytically designed to be
structurally stable, they saw the opportunity to gather some real world data
about how the booster would react to vibrations imparted by wind and other
outside forces.
So, they
proposed to set the Saturn swaying. And what better way to do that than to
exert force on the tower by having one group lie on their backs and push with
their feet while another pulled a rope tied to the opposite side?
Really,
what possibly could go wrong?
Setting
the stage for Saturn
The first
Saturn V rocket was never destined to launch to the Moon, let alone leave the
ground.
Assigned
the designation SA-500F, the full-size but not flight worthy rocket was
designed for use as a facilities demonstrator. Before NASA could launch
a Saturn V, the agency's engineers and technicians needed to test the
equipment that would be used to assemble, transport and prepare the booster for
liftoff.
On May 25,
1966, 500F made its first trip out to the pad atop a crawler transporter (the
same pad and crawler are still in use today by
the space shuttle). Testing continued successfully throughout the summer, only
interrupted by a series of minor problems.
On June 8,
the Saturn V was rolled back into the Vertical Assembly Building (VAB)
temporarily as Hurricane Alma moved close to the Florida coast. As the winds
remained below critical levels, the ground crew expressed surprise by the order
to return the rocket to its shelter. The general consensus among workers was
that the center's director, Kurt Debus, had called for the roll back as an
opportunity to practice a maneuver not yet tried.
Ray Byrd, a
Boeing mechanical systems engineer for the Saturn V's first stage, remembers
spending a lonely night monitoring pressures in the rocket as it was returned
to the VAB. There were concerns related to maintaining the integrity of the
stack were the pressures to fall. Byrd sat alone on the crawler beneath the
booster as it swayed in the driving rain and high winds.
Another
Boeing engineer, Art Scholz, was stationed as an observer in a cab on top of
the mobile launcher platform, where he reported measured wind velocities. Byrd
recalls the fear in Scholz's voice as he called back during gusts.
Byrd,
Scholz and the 500F made it safely inside the VAB that evening and two days
later, on June 10, the rocket returned to the launch pad for further fuel
loading tests.
During
propellant loading trials on Aug. 19, an 18-inch (46-cm) liquid oxygen (LOX) feed
line ruptured, dumping 800,000 gallons (three million liters) of fuel from the
storage tank at the pad. The loss of propellant caused the inner shell of the
LOX storage tank to collapse inwards 16 feet (4.8 meters). Re-pressurization of
the tank popped it back out again.
Testing
with the rocket was completed at the pad and on Oct. 14, it was brought to the
VAB to be destacked. There were tentative plans, never realized, to reassemble
SA-500F and repeat the facilities checkout operations at the other Saturn
launch pad, 39-B, the following summer.
Tennis
shoes and tug-of-war
What
happened next may never have been known -- let alone believed -- had a
long-lost film clip not surfaced...
Continue reading at
collectSPACE.com to learn the outcome of the 'Tennis Shoe Test' and to watch
the video.
Copyright 2008 collectSPACE.com. All rights reserved.
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