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Mineral Balance Study (M071)
Principal Investigator
Research Area:
Bone and calcium physiology
Metabolism and nutrition
Species Studied
Scientific Name: Homo sapiens Species: Human

Before the Skylab missions were flown, researchers predicted that the various stresses of space flight, particularly weightlessness, would bring about significant changes in the metabolism of the muscular and skeletal systems. The prediction was based on mineral and nitrogen balance studies of normal, healthy subjects during immobilized or inactive bed rest. Marked increases in the level of calcium leaving the body in the urine were observed in these ground-based studies. Significantly negative calcium balances in the body were observed during relatively short periods of bed rest. Related losses of nitrogen and phosphorus were also observed. In a seven-month bed-rest study, the elevated urinary calcium partially subsided during the third and fourth months of bed rest. Nevertheless, urinary calcium remained significantly higher than control levels for as long as bed rest continued, and it did not fall to normal levels until the subjects were back on their feet.

The only attempt at performing controlled metabolic observations in space flight prior to the Skylab missions was during the Gemini 7 flight in 1965. That relatively short study revealed modest losses of calcium and phosphorus and varied changes in the metabolism of other elements. The Mineral Balance Study for Skylab was designed to study the effects of long-duration space flight on the muscular and skeletal body systems. The experiment precisely measured changes in metabolic constituents, particularly water, calcium and nitrogen.

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Johnston RS, Dietlein LF. Medical results of the Skylab program. International Astronautical Federation (I.A.F.), XXVth Congress; 1974 Sep 30 - Oct 5; Amsterdam.

Johnston RS, Dietlein LF. Medical support and findings of the Skylab program. NASA Johnson Space Center; Houston, TX, United States. March 01, 1975. NASA TM X-58160. [NTRS]

Johnston RS, Stonesifer JC, Hawkins WR. Development of Skylab medical equipment and flight preparations. Acta Astronautica. 1975. Jan-Feb;2(1-2):69-84. []

Lane HW. Energy requirements for space flight. The Journal of Nutrition. 1992. January; 122(1):13-8. []

Leach CS, Altchuler SI, Cintron-Trevino NM. The endocrine and metabolic responses to space flight. Medicine and Science in Sports and Exercise. 1983; 15(5):432-40. []

Rambaut PC, Leach CS, Leonard JI. Observations in energy balance in man during spaceflight. American Journal of Physiology. 1977. November;233(5):R208-12.[]

Rambaut PC, Leach CS, Whedon GD. A study of metabolic balance in crewmembers of Skylab IV. Acta Astronautica. 1979. October;6(10):1313-22. []

Rambaut PC, Smith MC Jr, Leach CS, Whedon GD, and Reid J. Nutrition and responses to zero gravity. Federation Proceedings. 1977. April; 36(5):1678-82. []

Rambaut PC1, Leach CS, and Whedon GD. Metabolic energy requirements during manned orbital Skylab missions. Life Sciences and Space Research. 1977;15:187-91. []

Stokes J. An evaluation of Skylab habitability hardware. American Astronautical Society, Annual Meeting, 20th, 1974 Aug 20-22; Los Angeles (CA). Paper No.: 74-135.

Whedon GD, Lutwak L, Rambaut P, Whittle M, Leach C, Reid J, and Smith M. Effect of weightlessness on mineral metabolism; metabolic studies on Skylab orbital space flights. Calcified Tissue Research. 1976. August; 21 Suppl: 423-30. []

Whedon GD, Lutwak L, Rambaut PC, Whittle MW, Reid J, Smith MC, Leach C, Stadler CR, and Sanford DD. Mineral and nitrogen balance study observations: the second manned Skylab mission. Aviation, Space, and Environmental Medicine. 1976. Apr; 47(4):391-6. []

Whedon GD, Lutwak L, Rambaut PC, Whittle MW, Smith MC, Reid J, Leach C, Stadler CR, Sanford DD. Mineral and nitrogen metabolic studies, experiment M071. In: Johnston RS, Dietlein LF, eds. Biomedical Results from Skylab. Washington, DC: NASA Headquarters; 1977:164-174. NASA SP-377. [NTRS]

Whedon GD, Lutwak L, Reid J, Rambaut P, Whittle M, Smith M, Leach C. Mineral and nitrogen metabolic studies on Skylab orbital space flights. Transactions of the Association of American Physicians. 1974;87:95-110. []

Whedon GD, Reid J, Lutwak L, Rambaut P, Whittle M, Leach C, Smith M. Mineral and nitrogen metabolic studies on Skylab flights and comparison with effects of Earth long term recumbency. Life Sciences and Space Research XIV. Proceedings of the Open Meeting of the Working Group on Space Biology; 1975 May 29-Jun 7; Berlin (East Germany) .

Whedon GD. Changes in weightlessness in calcium metabolism and in the musculoskeletal system. Physiologist. 1982. December; 25(6):S41-4. []

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Data Information
Data Availability
Archive is complete. Data sets are not publicly available but can be requested.
Data Sets+ Request data

Calcium balance, feces
Calcium balance, urine
Calcium content, urine
Calcium loss
Calcium, total
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Skylab 2 05/25/1973 06/22/1973 28 days
Skylab 3 07/28/1973 09/25/1973 59.5 days
Skylab 4 11/16/1973 02/08/1974 84 days

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Pamela A. Bieri
Institutional Support
National Aeronautics and Space Administration (NASA)
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