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OCR for page 46
An Initial Review of Microgravity
Research in Support of
Human Exploration and Development of Space
4
Programmatic Issues
In the previous chapters of this report, an initial identification was made of
the scientific and related technological issues facing NASA's HEDS endeavor. In
looking specifically at mission enabling and enhancing technologies, the
committee identified several scientific challenges that need to be addressed by
the research community. It is clear that fundamental scientific questions in the
physical and biological sciences need to be answered before many exploration
technologies can be efficiently developed. MRD's major contribution to NASA is
its support of fundamental research that examines the role of gravity in physical
and biological systems, but there are steps that MRD can take to strengthen the
contribution of that science to HEDS. Discussed below are several points of
consideration and recommendations that the committee believes important to
MRD's support of the HEDS enterprise.
MRD should be prepared to stimulate and support critical microgravity
research to help discriminate among competing HEDS technologies, specifically
providing information so that NASA can make informed choices among them.
MRD should, on a continuing basis, assist NASA in identifying critical
technologies that would benefit future HEDS missions and then seek
opportunities in microgravity research to contribute to their efficient realization.
MRD should, however, remain both flexible and cautious in evaluating such
opportunities. Major advances in technology can result from basic research
undertaken without regard to current technological priorities, which have yet to be
even identified. In addition, the timing of such technological advances is often
unpredictable.
The process of gathering and exchanging information relevant to
deciding research selections that could support HEDS missions should be
strengthened. Specialized workshops, cross-divisional teams, advisory panels,
and study groups attended by mission technologists and microgravity scientists
are among the suggested mechanisms to achieve this recommendation. Such
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activities would encourage the exchange of ideas between technologists and
scientists, provide better communication and ongoing awareness of the
technology needs for MRD, and also allow timely transfer of microgravity
research findings to HEDS technologists.
The goals of HEDS involve the development of complex technological
systems that require, for example, the integration of knowledge from such
apparently disparate fields as biotechnology, fluid physics, and materials science.
Examples might include studies of biologically based systems and fluids
management systems that could address life-support needs or the multiple
disciplines required for in situ resource recovery. MRD may find it advantageous,
where appropriate, to initiate a limited number of projects focusing on cross-
disciplinary research topics, in order to develop experience in cross-disciplinary
research selection and project management. Various scientific disciplines must
be integrated in order to design and evaluate complex systems, and MRD could
provide the necessary research methodologies for this purpose.
While robust scaling laws involving the g level may be available for
some microgravity disciplines, allowing predictions and extrapolations between
microgravity and terrestrial g0, this usually does not hold true in more complex
systems. Furthermore, for many phenomena and processes affected by gravity
reduction, it is not yet known whether a threshold effect occurs at some g level.
This remains particularly true, for example, in biological areas, where it is difficult
to model multistep processes, which may include significant shifts in the relative
importance of gravity. Recognizing that some of the missions envisioned by
HEDS involve significant encounters with fractional g0 environments (lunar
gravity = 0.16 g0, Martian gravity = 0.37 g0), MRD should consider giving more
attention to studies conducted at fractional g0 where applicable to HEDS
technologies.
NASA's ongoing investments in automation and robotics are expected
to benefit both human and robotic HEDS missions, both in space and in terrestrial
and extraterrestrial settings. HEDS missions will often involve spacecraft
operations that are sufficiently far from Earth to demand high levels of
autonomous operations and control in part because of the unacceptably long time
lags associated with speed-of-light communications. Improved automated and
teleoperational capabilities can enhance the science and commercial return on
NASA's investment, reducing operating costs and improving safety and comfort
on space operations. MRD should carefully follow these efforts to make sure that
microgravity issues, especially for robotics, receive appropriate research
attention.
It is expected that the ISS will provide a unique platform for conducting
long-duration microgravity scientific research and assessing the efficiency and
long-term suitability of many technical systems important to HEDS. In addition to
its program of basic research aboard ISS, MRD should take advantage of the
station and its subsystems for test bed studies of science concepts applicable to
HEDS technologies. This could include, for instance, a role for applied
