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 from, protection, hostile, external and/or environment:
“Guns have metamorphosed into cameras in this earnest comedy, the ecology safari, because nature has ceased to be what it always had been—what people needed protection from. Now nature tamed, endangered, mortal—needs to be protected from people.”
—Susan Sontag (b. 1933)
“Freedom of religion, freedom of the press, and freedom of person under the protection of habeas corpus, and trial by juries impartially selected. These principles form the bright constellation which has gone before us, and guided our steps through an age of revolution and reformation.”
—Thomas Jefferson (1743–1826)
“A bargain is in its very essence a hostile transaction ... do not all men try to abate the price of all they buy? I contend that a bargain even between brethren is a declaration of war.”
—George Gordon Noel Byron (1788–1824)
“The manifestation of poetry in external life is formal perfection. True sentiment grows within, and art must represent internal phenomena externally.”
—Franz Grillparzer (1791–1872)
“In a land which is fully settled, most men must accept their local environment or try to change it by political means; only the exceptionally gifted or adventurous can leave to seek his fortune elsewhere. In America, on the other hand, to move on and make a fresh start somewhere else is still the normal reaction to dissatisfaction and failure.”
—W.H. (Wystan Hugh)