and two basic solutions have been suggested: to come straight
down, experiencing high g-forces but holding them to short
duration, or to follow a gradually descending path, with moderate
g-forces but long duration. Other possible solutions lie in
between. In any case, scientists concerned with the re-entry
problem wanted a mass of data on tolerance to deceleration
including data on the forces that would be required to produce
serious biological injury; and the tests on the Holloman
high-speed track helped supply the information needed.
No one expects that re-entry configuration
will call for exposure to forces even approaching the extreme
decelerations applied in some of the Holloman tests. On the other
hand, re-entry patterns are more problematical than the
acceleration anticipated in manned space travel. A year and a half
ago, before the various Soviet and United States satellites
contributed new knowledge on the density of the upper atmosphere,
re-entry patterns were even more problematical than they are now.
In reaching conclusions about human tolerance from chimpanzee test
results, moreover, it is desirable to have a wide margin for
possible error. At the very least whether for re-entry or for
other operational problems, it is comforting to know that fellow
primates have experienced forces above one hundred g's with only
minor injury, and in one case actually lived through a
deceleration of almost 250 g's.