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Field Journal from Kathy Southall - 3/7/96
SWIMMING WITH THE HUBBLE SPACE TELESCOPE
Next time you go to the swimming pool (deep end), jump into the middle of
the pool. Does your body sink or float to the top or stay somewhere in the
middle? If you sink, you are negatively buoyant. If you float, you are positively
buoyant. And if you are somewhere in the middle, you are neutrally buoyant.
So what does this have to do with the Hubble Space Telescope?
Here's my story.
I was underwater the first time that I came into contact with the Hubble
Space Telescope in the early 90's. As a NASA employee in Huntsville, Alabama,
I was currently working as a Space Station Freedom Project Office employee
for Marshall Space Flight Center (MSFC). However, all certified divers
at MSFC NASA could register at the Neutral Buoyancy Tank to do volunteer
work in the Tank. All of these volunteers underwent a rigorous underwater
test in order to enter the MSFC Tank that involved donning and doffing
scuba diving equipment at the bottom of a pool that contained 1.32 million
gallons of clear water as well as maintaining an up-to-date certification
in first-aid and cardiopulmonary resuscitation and passing a rigorous
physical examination.
On that particular day, I was assigned to take pictures of the HST Goddard
Space Flight Center simulation using an underwater movie camera (position
usually denoted as "the swim camera"). After the test, the video could
be used to review the happenings of the day. Procedures, that would later
be followed by the astronauts in space, could be corrected and equipment
redesigned in order to enhance extravehicular activity (EVA). During the
test, engineers, technicians, and other personnel monitored subjects from
a control room which contained several consoles with small monitors and
headsets connected to the communications network. These facilities allowed
the test director, test conductor, safety, and other personnel to view
the test and give instructions to the suited subjects and divers, observer,
safety, utility, and photography.
Thus water in the tank was used as the medium for neutral buoyancy to
simulate weight-lessness encountered in space. Underwater, the HST equipment
that was tested was actually a structural mockup, built for tank environment
and specifications. The suited subjects (participants wearing special
underwater pressurized space suits that were neutrally buoyant) were able
to perform critical EVA functions in preparation for the First Servicing
Mission by using this mockup.
Remember the saying, "practice makes perfect". NASA Goddard Space Flight
Center (in Greenbelt, Maryland where I now currently work in Operations
preparing for the Second Servicing Mission), was using the neutral buoyancy
tests as a tool to prepare for the upcoming First Servicing mission by
having subjects practice in the simulated weightless environment. Two
weeks of on-orbit servicing proved to be a brief interruption to scientific
operations compared with having to return the HST to Earth which would
have posed significantly greater risk of contamination or damage to the
Telescope's delicate components. As a result, unmatched space data and
pictures have resulted in increasing our knowledge of the Universe.
So, next time you go swimming (and you are neutrally buoyant as defined
in the first paragraph), remember reading this journal and pretend that
you are an Astronaut in Space getting ready to perform an EVA. Pick a
task, preferably a short one since you'll be holding your breath, that
would show you how different it is working in a weightless environment.
Remember, you will be allowed to flip upside down while performing this
task. Maybe attach small floats to a very heavy object that you would
not be able to easily lift on the ground, like a watermelon, and practice
moving it from one place to the next.
Who knows, maybe you'll be performing an EVA in space one day!
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