Microgravity Research in Support of Technologies for the Human Exploration and Development of Space and Planetary Bodies (2000) / Chapter Skim
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I Introduction
I Introduction
Pages 9-16
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From page 9... ...
It should be noted that the relative balance of resources devoted to these two categories of research will be determined by NASA priorities and funding availability and that this report does not attempt to make a recommendation in that regard. In the current HEDS enterprise there are crucial technological challenges associated with travel within the solar system and with the long-term survival and productivity of missions and, ultimately, extraterrestrial colonies in environments quite different from those found on Earth.
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From page 10... ...
Furthermore, the 1.28-second delay in communications signals between the Moon and Earth was an irritation, but the up-to-21-minute communication delay for radio transmissions between Earth and Mars makes two-way human conversation impossible and more fundamentally means that systems being operated either in the vicinity of Mars or on its surface must be operated autonomously. The free-space environment in the inner solar system has already been characterized, along with many of the aspects of other planetary bodies that could be involved in future HEDS missions.
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From page 11... ...
, and in many respects, Mars would be much more habitable during extended human stays than the Moon. A variety of other planetary bodies are of interest to future HEDS missions, including Jupiter's Galilean satellites, Europa and Callisto, which are now believed to contain liquid water oceans beneath their very cold water-ice shells.
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From page 12... ...
This definition includes the steady gravitational environments found on the surfaces of planetary bodies such as the Moon and Mars, where the gravity level is a significant fraction of Earth's gravity, along with the highly unsteady, near-zero acceleration environments that exist on spacecraft. Both types of microgravity environment are integral to HEDS missions involving extraterrestrial bodies, but they represent very different areas of microgravity research.
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From page 13... ...
identifies the physical bases for microgravity sensitivity and describes the associated phenomena. A logical symmetry between Chapters III and IV arises from the links between them: microgravity sensitivities generate potential failure modes in the subsystems; the need to improve subsystem efficiency drives the generation of relevant new scientific questions associated with microgravity-induced sensitivity.
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From page 14... ...
Terrestrial gravity fields provide reliable separations based on density differences; in the near absence of gravitational forces, phases of different density do not spontaneously separate. The lack of phase separation in microgravity has severely compromised a range of promising technologies associated with all HEDS functions, from propulsion to sanitation.
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From page 15... ...
1993. Asteroidal resource opportunities suggested by meteorite data.
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