Protection From Hostile External Environment
- Radiation: Some very large space habitat designs could be effectively shielded from cosmic rays by their structure and air. Smaller habitats could be shielded by stationary (nonrotating) bags of rock. Sunlight could be admitted indirectly via mirrors in radiation-proof louvres, which would function in the same manner as a periscope.
- For instance, 4 metric tons per square meter of surface area could reduce radiation dosage to several mSv or less annually, below the rate of some populated high natural background areas on Earth. Alternative concepts based on active shielding are untested yet and more complex than such passive mass shielding, but usage of magnetic and/or electric fields to deflect particles could potentially greatly reduce mass requirements.
- If a space habitat is located at L4 or L5, then its orbit will take it outside of the protection of the Earth's magnetosphere for approximately two-thirds of the time (as happens with the Moon), putting residents at risk of proton exposure from the solar wind.
- See Health threat from cosmic rays
- Heat rejection: The colony is in a vacuum, and therefore resembles a giant thermos bottle. The sunlight to radiated energy ratio can be reduced and controlled with large venetian blinds. Habitats also need a radiator to eliminate heat from absorbed sunlight and organisms. Very small habitats might have a central vane that rotates with the colony. In this design, convection would raise hot air "up" (toward the center), and cool air would fall down into the outer habitat. Some other designs would distribute coolants, such as chilled water from a central radiator.
- Foreign objects: The habitat would need to withstand potential impacts from space debris, meteoroids, dust, etc.
Radar will sweep the space around each habitat mapping the trajectory of debris and other man-made objects and allowing corrective actions to be taken to protect the habitat. Meteoroid strikes would pose a risk to a space habitat much stronger than they do to the Earth, unless there should be developed a method to avert them, because a space habitat does not possess a sheltering atmosphere.
Read more about this topic: Space Habitat
Famous quotes containing the words protection, hostile, external and/or environment:
“After so many historical illustrations of the evil effects of abandoning the policy of protection for that of a revenue tariff, we are again confronted by the suggestion that the principle of protection shall be eliminated from our tariff legislation. Have we not had enough of such experiments?”
—Benjamin Harrison (1833–1901)
“We fear our neighbor’s hostile mood because we are afraid that this mood will lead him to penetrate our secrets.”
—Friedrich Nietzsche (1844–1900)
“It is not a certain conformity of manners that the painting of Van Gogh attacks, but rather the conformity of institutions themselves. And even external nature, with her climates, her tides, and her equinoctial storms, cannot, after van Gogh’s stay upon earth, maintain the same gravitation.”
—Antonin Artaud (1896–1948)
“Autonomy means women defining themselves and the values by which they will live, and beginning to think of institutional arrangements which will order their environment in line with their needs.... Autonomy means moving out from a world in which one is born to marginality, to a past without meaning, and a future determined by others—into a world in which one acts and chooses, aware of a meaningful past and free to shape one’s future.”
—Gerda Lerner (b. 1920)