PRINCIPAL INVESTIGATOR (S ): Pauline B. Mack, George P. Vose, Fred B. Vogt, and 



Paul A. LaChance 



EXPERIMENT TITLE/NUMBER : Bone Demineralization, M006 



PROGRAM/MISSION : Gemini 4, 5, 7 



CLASSIFICATION : Human 



DISCIPLINE(S) : Musculoskeletal 



OBJECTIVES : To find the effect upon the human skeletal system of prolonged 

 weightlessness and immobilization associated with confinement for a period of 

 days in the Gemini spacecraft . 



PROTOCOL : The measurements of bone demineralization were made using 

 radiographic bone densitometry. Radiographs were made pref light and 

 postflight of the left foot in lateral projection and the left hand in 

 posterior-anterior projection. They were taken at F-10 days and F-3 days, 

 at R+0, R+24 hours, R+11 days, and R+47 days. Sections of the os calcis, 

 talus and hand phalanges were evaluated for changes in skeletal 

 mineralization . 



EQUIPMENT : Analog computer and X-ray unit. 



RESULTS : Postflight X-ray densitometry showed decreases in bone mass. How- 

 ever, rapid gains were found during the first 12 hours after recovery. The 

 losses in the crewmen of Gemini 7 tended to be lower in all anatomical 

 sections than those in the Gemini 4 and 5 crewmen who consumed about 1/3 as 

 much calcium inflight. 



CONCLUSIONS : The level of food intake undoubtedly has been one of the major 

 parameters accountable for the differences in levels on mineral loss by the 

 astronauts. The Gemini 7 astronauts engaged in isotonic and isometric 

 exercises and slept for longer periods than Gemini 4 and 5 astronauts which 

 may also explain the differences. The findings of this study show that time 

 is not the chief factor responsible for skeletal loss during space flight. 

 Skeletal losses were replaced within short period after recovery. 



PUBLICATIONS : 323, 324, 325, 326, 367, 370, 371, 372, 541 



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