(NRC 2002; RAND, 2002), the committee concludes that resources are insufficient to perform the additional work necessary to mitigate the risks identified in the BR to acceptable levels.

Recommendation 4.2

The committee recommends that NASA perform regular, detailed assessments of the additional risks to the conduct of the President’s 2004 vision for space exploration posed by the lack of available resources to fully address the issues posed in the BR. This assessment should then be used to make early strategic decisions regarding issues such as, but not limited to, the following:

1. How to provide support for a microgravity research platform that will have the resources (crew time, up-mass, facilities, and power) for the large amount of work necessary to validate countermeasures; achieve Technology Readiness Level 7 for life support systems sufficiently early in the design phase to allow their integration into the overall vehicle; and demonstrate the utility of medical procedures in microgravity.

2. How to support the extensive behavioral research program that would be necessary to validate processes or countermeasures such as select-in–select-out criteria (both for individual crew members and for a composite crew), issues related to cultural diversity, crew interactions, and isolation or stress-induced hazards. These issues may well require long lead times to study adequately.

ADDRESSING THE CHALLENGES POSED BY THE SMALL SAMPLE SIZE

A number of criteria can be considered in flight crew sizes: (1) resource requirements such as funding, vehicle capacity, and mission objectives; (2) standards for assessing quality control or hardware reliability; and (3) statistical power for performing research. Given the importance that NASA places on each of these criteria, the committee recognizes that NASA must consider all three sets of factors when determining crew sizes.

Regardless of which criteria are used to derive crew sizes, achieving



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