The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

12 aerospace medicine
aerospace medicine
A branch of medicine that deals with the effects on the
human body of flight and with the treatment of disorders
arising from such travel. It has two sub-branches: (1) aviation
medicine, concerned with flight in Earth’s atmosphere
and under at least normal Earth gravity; and (2)
space medicine, concerned with flight beyond the atmosphere,
in which humans are typically exposed to a fraction
of normal Earth gravity.
Aerospace medicine has its roots in the eighteenthcentury
physiological studies of balloonists, some of
whom were physicians. In 1784, a year after the first
balloon flight by the marquis d’Arlandes and the
French physicist Jean Pilâtre de Rozier (1756–1785), the
Boston physician John Jeffries (1744–1819) conducted
the first study of upper-air composition from a balloon.
The first comprehensive studies of health effects
during air flight were carried out by the French physician
Paul Bert (1833–1886), professor of physiology at
Paris University, who pioneered the use of oxygen to
prevent hypoxia. His work was continued in 1894, by
the Viennese physiologist Herman Von Schrötter, who
designed an oxygen mask with which meteorologist
Artur Berson (1859–1942) set an altitude record of
9,150 m.
With the advent of the airplane, medical standards for
military pilots began to be established. In 1917, physician
Theodore Lyster (1875–1933) set up the Aviation Medicine
Research Board, which opened a research laboratory
at Hazelhurst Field in Mineola, New York, in January
1918. The School of Flight Surgeons opened in 1919, and
a decade later the Aero Medical Association was founded
under the direction of Louis Bauer (1888–1964). In 1934
facilities, including a centrifuge, were built at Wright
Air Field to study the effects of high-performance flight
on humans. Technical advances included the first pressure
suit, designed and worn by the American aviator
Wiley Post (1900–1935) in 1934, and the first anti-g suit,
designed by the Canadian medical researcher Wilbur
Franks (1901–1986) in 1942. In an effort to improve
restraint systems for military jet aircraft, the American
flight surgeon John Stapp conducted an extraordinary
series of tests in the 1950s on a rocket-powered sled. Aviation
medicine was recognized as a specialty of preventive
medicine by the American Medical Association in
1953, and saw its name change to aerospace medicine in
1963.
aerothermodynamic border
An altitude, at about 160 km, above which the atmosphere
is so thin that an object moving through it at high
speed generates virtually no surface heat.
AFSATCOM (Air Force Satellite Communications
System)
A satellite-based system that provides high-priority communications
for command and control of American
global nuclear forces. It became operational on May 19,
1979. AFSATCOM equipment rides piggyback on other
military satellites, including, originally, FLSATCOM
satellites and, currently, Milstar satellites.
afterburning
The irregular burning of fuel left in the combustion
chamber of a rocket after cutoff.
aft-firing thrusters
Small rocket engines located at the tail of a spacecraft and
used for maneuvering.
Agena
A versatile space vehicle developed by the U.S. Air Force
that served as an upper stage on a variety of boosters,
including the Thor, Atlas, and Titan IIIB. It could carry
a satellite into a precise orbit and then launch it back
toward Earth for recovery, carry experiments into orbit
and radio data back to Earth, and place small space probes
on interplanetary paths. One version of the Agena served
as a target for docking experiments during the Gemini
program. Development of the Agena began in 1956. On
Agena The Agena Target Docking Vehicle, seen from the
Gemini 8 spacecraft. NASA