Life Sciences in the Space Program 



organogenesis, and developmental timing; and the role of gravity in flowering and 

 fertilization. 



Developmental Biology of Animals. The goals of the research program in this 

 area are to determine the effect of gravity on pattern specification in embryonic 

 development; to investigate the involvement of gravity in cell differentiation, 

 histogenesis, organogenesis, and overall system integration during the normal 

 development of organ systems in various vertebrate and invertebrate species; and 

 to learn at all levels of organization the extent to which gravity influences 

 reproduction and the normal development, growth, maturation, and aging of 

 organisms. Current research focuses on such topics as hypergravitv and 

 mammalian development, the effects of gravity upon the polarity of amphibian 

 eggs, amphibian development in microgravity, vestibular system development, 

 cytoskeleton formation, the role of gravity in mammalian fertilization and 

 development, and the effect of hypergravitv upon the reproductive capabilities of 

 various rodent species. Ground-based studies using hypergravitv (centrifuges) and 

 gravity vector randomization (clinostats) are employed to develop techniques and 

 baseline data for studies to be conducted on animals in space. The research will 

 focus on the animals' conception and development. 



Biological Adaptations to Gravity 



The objectives of this research are to: 



• Determine the role of gravity in regulating metabolic rate and products, fluid 

 dynamics, and biorhythms 



• Understand the effects of gravity on biological support structures and basic 

 mechanisms of mineral and hormonal metabolism 



• Identify the biological effects of the interaction of environmental factors, such as 

 temperature and light, with gravity and determine the mechanisms involved 



• Use the space environment as a tool to determine the factors that control the 

 structure and function of organisms. 



Animal Adaptations to Gravity. Current research on animal structural 

 adaptations to gravity seeks to determine whether gravity directly affects cellular 

 ultrastructure or exerts its effect extracellularly and to elucidate the mechanism(s) 

 involved. Metabolic studies seek to determine whether temperature regulation is 

 gravity dependent, whether the mechanisms controlling temperature regulation are 

 calibrated for 1 g, and whether normal terrestrial gravity plays a role in establish- 

 ing basal metabolic rate and biorhythms. 



The research program makes extensive use of vertebrate and invertebrate ground- 

 based models to examine the different mechanisms by which life copes with 

 gravity. This is done for three reasons: 1) to study more easily phenomena 

 previously observed only in space, 2) to correlate terrestrial analogs of phenomena 

 seen in space flight, and 3) to provide adequate experimental controls. This 

 n h shows that altering the local gravitational field can have a profound 



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