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History of Research in Space Biology
and Biodynamics
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- Tolerance to Total Pressure
Change: Task 78504
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- [79] Another task
of Project 7850 is Tolerance to Total Pressure Change (Task
78504), which seeks to determine human and animal responses to
negative or positive total pressure change in the range of one to
ten atmospheres occurring in .005 to five seconds and in single or
multiple cycles.46 Task scientist from 1956 until he left the service
in mid-1958 was Captain (Doctor) Donald F. Patterson, an Air Force
veterinarian who like Captain Recht was assigned to the Veterinary
Services Section of the Aeromedical Field Laboratory's Laboratory
Services Branch (now Laboratory Branch). At present the task
scientist is Lieutenant William Ward.
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- In explaining the objectives of this task,
Captain Patterson pointed out that the physiological effects of
47
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- ... increased pressures on the human body
surface have been studied in relation to undersea diving, but
investigations in this area have been largely concerned with
slowly increasing pressures such as are encountered in descent
beneath water. The effects of abruptly increasing, or rapidly
cycling pressures as are exerted on the body due to windblast and
deceleration during high speed bailout have not been adequately
studied... Abrupt external pressures, transmitted hydraulically
through the blood vessels, may exceed the rupture points of small
vessels in various organs including the eye.
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- As the above quotation indicates, this
task is another of the research activities of the Aeromedical
Field Laboratory with a bearing on high-speed escape from
aircraft. But the range of possible applications extends far
beyond the escape problem. The physiological effects to be studied
by this research task are also present in explosions, for instance
atomic blasts, and are relevant to various problems of manned
space travel. Recent interest in the use of a fluid medium for
attenuating the acceleration and deceleration forces encountered
in rocket flight makes experimentation on the effects of various
pressure patterns extremely pertinent; conceivably, the
attenuation of g-forces would be offset (at least in part) by a
sharp buildup of pressure, caused by the g-loading and increased
weight of the fluid itself. Finally, there is a need for basic
research to distinguish the effects of pressure change
per se from the effect of other forces that in practice
may be applied at the same time. However, the Aeromedical Field
Laboratory is primarily interested in positive not negative
pressure changes-in compression not decompression-since the latter
is already a subject of extensive research at the Aero, Medical
Laboratory of Wright Air Development Center. Some work is also
being done at different locations on abrupt positive pressure
change-using shock tubes and other specialized test facilities-but
there is need for much more research on the
subject.48
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- Although the Aeromedical Field Laboratory
has been devoting intermittent...
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[80] (MISSING PHOTO)
- Car Crash With Dummy Subject
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- [81] efforts to
this task since 1955, no actual tests have yet been performed. As
a result of manpower and fund limitations, the task has not
progressed beyond the stage of planning and preparations. Certain
items of test equipment have been assembled, and members of the
laboratory staff are familiarizing themselves with their
operation. Other items have been designed (with help from other
units of the Air Force Missile Development Center's Directorate of
Research and Development), including principally a chamber capable
of exerting "pressure in the range of 1 to 5 atmospheres to the
body surface of rabbits."49 But the Center is still in the process of obtaining
the apparatus, which probably will not be available until the
latter part of 1958. It will then be used in exploring the effect
of varying combinations of magnitude, onset, and duration of
compression on animal test subjects. Ultimately, it may be
desirable to obtain larger and more exacting equipment for testing
similar pressure changes with primates and human subjects, but
small animals must first lead the way.50
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