|Weightless Astronaut - Physiological Effects|
KEY ASSUMPTIONS: The fundamental physiological assumption here is that the astronauts must experience a 1G environment at least 6 hours out of every 24 hours. This interval is expected to offset physiological conditions that generally weaken the astronauts overall physical profiles with strong potentials for direct impact on cognitive functioning as well. At the same time, it is recognized that the daily moving in and out of a gravity environment can also be destabilizing. What is not yet understood is whether this daily transition can eventually be tolerated by spacecraft crew without disorientation or discomfort.
SPACECRAFT CONFIGURATION: The spacecraft in this regard is essentially an extremely large, traveling space station that includes several interconnected modules. The central module is the gravity room (GraviTmod) that is a centrifuge system that gradually places astronauts into a 1G environment. As noted above, they remain in this environment for a total of 6 hours each day. The image of the Stanford Torus is one design example of a large centrifuge system that serves as the GraviTmod of the spacecraft.
- The 600 ft length is only the arm radius so the entire GraviTmod is more than 1200ft in diameter.
- Another critical question is whether a centrifuge of this size will induce the gyroscopic effect that could effect both the maneuverability of the spacecraft-spacestation, and astronaut physical sense of balance. An excellent presentation on this issue was done by NASA. You may review that document here (pdf file download).
- Another important consideration is long-term astronaut explorations of planetary and asteroid bodies with little or no gravity. This does not seem either wise or productive considering the physiological and possible neurological impact of prolonged weightlessness. One technique would be to deploy robonauts instead of human astronauts for explorations in these environments. Another would be to consider the construction of a "on-the-ground" gravity module that served as home base for astronauts involved in long-term planetary explorations. In this concept they could at least be in a 1G environment for a safe daily interval to sustain their physical well being.
This author is a dedicated advocate for deep space exploration, but at the same time he recognizes the many human factor challenges that must be considered and met to insure a safe and productive exploration program. Weightlessness is only one vital consideration. In some of our solar system planets, there is little or no atmosphere and little or no protection from the solar winds and high cosmic radiation. These considerations must also be addressed before we can plan on sustained and safe human exploration of these planetary bodies.
Stanford Torus spacecraft design
Weightless Astronaut annotated image:: Courtesy Daniels and Daniels/Scientific American/Astrobiology