Immobilization associated with flight has been found to definitely be associated
with decreases in skeletal density in human subjects in prior studies. Using
the x-ray radiographic method, this study was to find changes in bone density
that might occur during weightlessness in the non-human primate.
Several series of bone radiographs were taken preflight to ascertain initial
skeletal density in seventeen anatomic sites. The values obtained from scanning
sections of bones were equated in terms of mass of calcium hydroxyapatite, the
major mineral component of bone. Additional radiographs were also taken postflight.
Postflight density losses at the sites analyzed ranged from -1.71% to -17.52%,
compared to 0.12% to -10.72% for ground controls. The bone density losses in
the flight animal were considered to be due to immobilization coupled with the
aggregate stresses of the flight environment.
Mack, P.B.: Bone Density Changes in a Macaca nemestrina Monkey During the Biosatellite
III Project. BIOSPEX: Biological Space Experiments, NASA TM-58217, 1979, p.
122.
Mack, P.B.: Bone Density Changes in a Macaca nemestrina Monkey During the Biosatellite
III Project. Aerospace Medicine, vol. 42, 1971, pp. 828-833.
¥ = publication of related ground-based study