PRINCIPAL INVESTIGATOR (S ) : Paul C. Rambaut , Malcolm C. Smith, Pauline B. 



Mack, and John M. Vogel 



EXPERIMENT TITLE/NUMBER : Skeletal Response 



PROGRAM/MISSION : Apollo 14, 15, 16 



CLASSIFICATION : Human 



DISCIPLINE(S) : Musculoskeletal 



OBJECTIVES : To determine effects of weightlessness on bone during prolonged 

 space flight. 



PROTOCOL : A scan was made of the configuration of the heel .os calcis and arm 

 (radius and ulna) using a ' I source. It was made in 3 directions with a 

 total of 4096 data points taken. Scans were made at F-1 month, F-2 weeks, F-1 

 week, and R+4. The bone scans were made using photon absorptiometry. 



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 EQUIPMENT : Rectilinear bone mineral scanner, I source, Nal scintillator. 



RESULTS : No mineral losses were observed in os calcis . radius, or ulna in 

 Apollo 14. (There were significant increases in fat on the plantar side of 

 the os calcis in the Command Module Pilot of Apollo 14.) In Apollo 15, there 

 was some mineral loss in the bone, but none in Apollo 16. In all missions 

 there was greater variation in mineral loss in the ulna. A significant change 

 in the soft tissue composition of the Command Module Pilot in Apollo 14 was 

 found, but none in Apollo 15 or 16. 



CONCLUSIONS : Loss of mineral from bone incident to periods of weightlessness 

 was comparable to that observed in bed rest subjects but the magnitude was not 

 as severe. If these losses were allowed to continue unabated for a prolonged 

 period of time, the consequences might be more serious since the losses were 

 probably not confined to the bones described. Because of either biological 

 variability between subjects or factors not yet identified, not all crewmen 

 were similarly affected during the 10- to 12-day missions. These studies can 

 be used to construct a time-effect curve that can be compared with the bed 

 rest data, thus permitting a reasonable degree of prediction for longer space 

 flight missions. 



PUBLICATIONS : 370, 441, 535, 537, 540 



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