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History of Research in Space Biology
and Biodynamics
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- - PART II -
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- 1. Important Technological
Developments
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- [11] Many
of the techniques developed during
the pioneering period 1946-1952 in the use of both rockets and
balloons for space biology research1, have continued to be useful in the later period of
more intensive activity. Certain engineering techniques and
methods of operation developed since then, however, have helped to
make possible research accomplishments of far greater
significance. Balloon operations from 1950 through 1952, for
instance, provided a wealth of experience in balloon and capsule
techniques, but only since 1953 have they amassed a significant
quantity of data on such problems as the biological effects of
cosmic rays.
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- The greater effectiveness of balloon
flights from 1953 to the present has been partly the result of an
increase in human and material resources devoted to the program.
It also reflects the transfer of major launch operations to
localities in the northern United States where, as now became
apparent,2 the magnetic field of the earth converging on the
poles permitted a much more significant exposure to primary cosmic
radiation than at comparable balloon altitudes at the latitude of
Holloman Air Force Base, New Mexico. Since the spring of 1953, in
fact, space biology flights conducted at Holloman have been
primarily to test balloon and capsule techniques or to expose
biological control specimens to the relatively weaker radiation of
lower geomagnetic latitudes. Finally, since 1953 there has been a
sharp technical improvement in flight performance due in part to
previous efforts only now beginning to bear fruit, and in part to
continuing research and development by aeromedical scientists,
balloon manufacturers, and others, both at Holloman and
elsewhere.
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- One noteworthy development, first employed
on space biology flights in 1953, was the perfection of radio
command cutdown as a method of terminating balloon flights. Two
different command cut-down devices were used in that year, one
developed by the Aero Medical Laboratory at Wright Field and the
other provided by the aeronautical laboratories of General Mills.
This new method did not replace but came to supplement the earlier
preset timer, which had been inadequate by itself because it might
automatically let down a balloon capsule during a thunderstorm
that would interfere with both radio and visual tracking, or
perhaps drop an experimental cargo into the heart of an
inaccessible area. At least now the flight could [12] be shortened
if these difficulties were anticipated.3
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- Tracking and recovery techniques also
improved steadily. Panel trucks equipped as radio monitoring and
tracking stations supplemented the work of tracking aircraft.
Improved balloon-borne antenna systems permitted an equipment
package to send reliable signals even after it landed, thus
helping search parties to find it. Any improvements in tracking
and recovery were of course particularly important for space
biology flights, which have always required prompter recovery than
most. A lost balloon capsule might be returned months later, in
response to the twenty-five-dollar reward notice posted on it, but
by then all biological specimens would have
perished.4
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- Since 1953, environment control for animal
capsules has likewise undergone considerable improvement. One of
the most ingenious developments was the use of boiling water as a
coolant, a system pretested in the Standards Laboratory at
Holloman and successfully flight-tested on balloon missions in the
fall of 1953. The device is based on the principle that, because
of decreased atmospheric pressure, water boils at lower
temperatures when placed at higher elevations. At an altitude of
about 112,000 feet, for example, water boils at thirty-two degrees
Fahrenheit--the temperature where at sea level it would become
solid ice. Therefore, water could be made to boil at high altitude
simply by placing it in a container vented to the lower outside
atmospheric pressure. When air within the sealed capsule was
circulated around the container, vapor from the boiling water
carried off heat from the capsule.5
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- Other improvements of equal or greater
importance were steps taken to reduce the over-all weight of the
capsules. During 1954 and 1955, the weight of the standard animal
capsule was reduced from one hundred sixty-five pounds to about
seventy. The direct result of this accomplishment is that
identical balloon equipment can now attain significantly higher
altitudes with the same biological specimens.6
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- Flight performance also benefited greatly
from continued improvements in balloon launch techniques. At
Holloman, the "covered wagon" technique, whereby a small or
medium-size balloon could be protected during launch by inflating
it on a vehicle with high headboard and nylon top, had been
perfected and used during the pioneering years. Next came the
shroud-inflation technique, which held the balloon beneath a large
fabric cap during inflation.
This system was later improved upon
by using the crane-launch method, in which the delicate cargo is
carefully suspended from the crane's boom while the balloon cell,
at the opposite end of the load line, is undergoing inflation.
And, by the close of 1957, these techniques were giving way to
still other newly-devised methods.7
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- To be sure, these and other innovations in
balloon techniques were not perfected solely for space biology
flights. The Holloman Balloon Branch launched 683 plastic-type
balloons in fiscal years 1951 through 1957, and only a small
fraction of these were for cosmic radiation studies or other tasks
of the Aeromedical Field Laboratory. The shroud-inflation
technique, for instance, resulted from an effort of the Holloman
unit to meet requirements for the manned balloon phase of Wright
Air Development Center's Project 7218, Biophysics of Escape. Space
biology studies, however, benefited from all major technological
improvements, including those developed away from the Air Force
Missile Development Center by private balloon technicians; and, in
turn, the experience accumulated on flights for the Aeromedical
Field Laboratory was of benefit to other balloon
operations.8
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- Meanwhile, the balloons themselves were
growing both bigger and better. One landmark was the introduction
of the two-million-cubic-foot plastic balloons. The first of these
to be used on a cosmic radiation flight was manufactured by Winzen
Research, Incorporated, and launched 18 July 1955 at Fleming
Field, South Saint Paul, Minnesota. It reached an altitude of over
120,000 feet. It was followed by a similar balloon launched the
very next day which reached 126,000 feet, a record not only for
the Aeromedical Field Laboratory program but also (to that date)
for polyethylene balloons in general.9
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- Neither of these balloons was intended to
set a flight-duration record, but time aloft on individual flights
was also increasing steadily. This fact, plus the growing
reliability of flight performance and recovery, permitted much
longer exposure of individual specimens by reflying them on two or
more consecutive flights. Because of greater uncertainties in
recovery, capsule performance, and the like, this procedure of
multiple flights was virtually impossible prior to 1953, but since
that time it has become commonplace. In 1954, for example, test
specimens were reflown on two separate flights for a total of
seventy-four hours and thirty-five minutes at an altitude between
82,000 and 97,000 feet, mostly above 90,000.10
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