Tuesday, November 25, 2008

Why are Satellites so Important?-part 2 (4 of 9)

Satellites are also used to observe space, to find out the mysteries, laws and events of the cosmos. Space is ideal for this because most of the emissions from space, x-ray, gamma and such, are blocked out by the Earth’s atmosphere. This atmospheric shield is perfect to sustain life, but becomes rather annoying when you want to know what goes on beyond Earth and in space. Figure 3 shows clearly the percentage of each electromagnetic wavelength that goes through the Earth’s atmosphere, and some of the satellites utilized to observe space on their differing wavelength frequencies. The far left represents gamma rays, x-rays and ultraviolet light. The rainbow on the left side represents the visible light spectrum, which is partially blocked by the atmosphere but is monitored by the Hubble and land-based telescopes. The middle is the infrared range. The right shows the only range that is let fully though, the mid-range radio waves, which are monitored on Earth. The chart clearly shows that the range of full and even partial clarity of wavelength is small, showing the necessity of space-observing satellites. With all of the additional wavelengths to study, it increases that many more chances to learn about the universe.
So if these satellites are becoming so increasingly important, is there so much space trash? The space age is only 45 years old, but already the 680.4 tons of space debris make placing anything in space hazardous, especially the more fragile elements of satellites. But if the larger fragments, if objects the size of a softball are considered large, can demolish a satellite with one errant twist in an orbit, why are the smaller fragments, from the .4 and 3.9 inch range, are the ones that are classified as threats by the debris scientists. The smaller debris are almost untrackable and can do considerable damage, because they cannot be detected but can still mutilate spacecraft. But even the tiniest debris, the paint chips the size of a fingernail, are hazardous, for they can form clouds of speeding fragments that can strip an object with the destructive force of a sandblaster, corrupting the satellite elements.

Figure 3 was created by NASA and the European Space Agency (ESA)

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