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:
“We cannot spare our children the influence of harmful values by turning off the television any more than we can keep them home forever or revamp the world before they get there. Merely keeping them in the dark is no protection and, in fact, can make them vulnerable and immature.”
—Polly Berrien Berends (20th century)
“If you meet a sectary, or a hostile partisan, never recognize the dividing lines; but meet on what common ground remains,—if only that the sun shines, and the rain rains for both; the area will widen very fast, and ere you know it the boundary mountains, on which the eye had fastened, have melted into air.”
—Ralph Waldo Emerson (1803–1882)
“No real “vital” character in fiction is altogether a conscious construction of the author. On the contrary, it may be a sort of parasitic growth upon the author’s personality, developing by internal necessity as much as by external addition.”
—T.S. (Thomas Stearns)
“We learn through experience and experiencing, and no one teaches anyone anything. This is as true for the infant moving from kicking to crawling to walking as it is for the scientist with his equations. If the environment permits it, anyone can learn whatever he chooses to learn; and if the individual permits it, the environment will teach him everything it has to teach.”
—Viola Spolin (b. 1911)