• Muscle physiology,

  • Cardiovascular and pulmonary systems,

  • Endocrinology and nutrition,

  • Immunology and microbiology,

  • Radiation biology, and

  • Behavior and performance.

In order to assess the degree to which NASA’s research programs will meet the agency’s needs for biomedical knowledge in the next 10 years, the committee compared current and planned research to the recommendations made in the Strategy report. Within this context, the committee attempted to answer the following questions.

What Is the Balance of Discipline Areas in NASA’s Biomedical Research Program?

The Strategy report gave the highest overall priority to specific research questions dealing with bone and muscle loss, changes in the function of the vestibular and sensorimotor systems, orthostatic intolerance, radiation hazards, and the physiological and psychological effects of stress. Although the committee found the balance of NASA research between the various biomedical disciplines to be generally consistent with the relative emphasis given to them in the Strategy report, many of the specific research topics given the highest overall priority are still to be addressed. Noted below is the degree to which these research topics appear in the current program. It should be kept in mind that many of the Strategy report recommendations called for specific microgravity investigations that cannot be carried out until appropriate flight opportunities again become available.

As recommended, mechanistic studies and the use of ground-based animal models to understand changes in bone and muscle during and after spaceflight are being emphasized in NASA’s current program. Preliminary ground studies of the relationship between exercise activity and protein-energy balance have also been started. Implementation of recommendations to collect in-flight astronaut data on bone loss and hormonal profiles must await flight opportunities.

Some preliminary investigations have been carried out that are relevant to the recommendation for in-flight recordings of signal processing following otolith afferent stimulation. However, the recommendation to study the basis for compensatory vestibulomotor mechanisms on Earth and in space has not yet been addressed. The performance of the recommended microgravity studies on neural space maps and pattern learning in the vestibulo-oculomotor system will depend on the availability of flight opportunities.

Mechanistic studies of total peripheral resistance responses during postflight orthostatic stress have been conducted on the recent Neurolab mission and in the cardiovascular laboratory at JSC. The Mir cardiovascular experiments were relevant to the recommendation to examine cardiovascular changes on long-duration missions. However, inadequate plans exist to monitor these changes on the International Space Station. Current pulmonary studies focus on the issue of decompression sickness but do not address aerosol deposition and respiratory muscle function.

Studies to examine the space radiation-induced risks of cancer and central nervous system damage are being carried out by NSBRI investigators at new facilities at Loma Linda University for proton studies and at Brookhaven for heavy ions. These will provide greatly improved access to investigators for relevant studies. Flights are not yet available for the recommended study of the combined effects of radiation and stress on the immune system, and no preliminary ground studies on this issue appear to be planned.

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