Gold foil in space Bashny.Net

I'm sure many of you have seen during the preparation of spacecraft frames constantly flashing details that are wrapped in gold foil. Perhaps the foil used for insulation, but immediately begs the question - why is it gold? Let's find out what function it performs.




As is known, there is solar radiation, which affects the Earth's atmosphere and is the main source of energy for all processes of natural world. From the graph, which clearly shows the intensity, it is seen that the peak falls on the visible spectrum, although a large proportion of the radiation is and IR and UV ranges:



Therefore, equipment that should work in space, it is necessary to protect as much as possible from the effects of infrared radiation. To do this, some parts of the spacecraft is wrapped in a metal heat-insulating "foil". Usually such "reflectors" are made of aluminum, silver, copper or gold. However, in the aerospace industry is widely used gold. The graph below shows the change of the reflection coefficient for each metal, depending on the wavelength:



All four metal cope well with the reflection of infrared radiation, the ratio is close to 100% of wave length of 700 nm. So why use it gold? Because, unlike copper or silver, gold does not corrode (For the same reason it is widely used in the manufacture of printed circuit boards), and the gold is easier to work with than aluminum (Recall that the case with aluminum foil when it crush and then re-deploy).

In general, the "gold leaf" is by no means only of gold. This multilayer metallized film, and different parts of spacecraft wrapped in different types of films, depending on the needs. There is here a PDF from NASA, which it describes in detail, with pictures!



Often, as a material used for Kapton film, which in turn applies a thin layer of gold, aluminum and silver. The last two metals can produce golden color with a very thin spraying.

A good example is the use of gold plating technology modern spacesuits: filters helmets are made of polycarbonate plastic (protection against UV), which are also covered with a thick layer of gold is sufficient to protect the astronaut from solar radiation. As a result, the filter passes no more than 35% of the light that completely protects the eyes from external influence of infrared radiation, which is outside the visible spectrum, and therefore can quietly cause irreparable damage to sight astronaut. "Gold Filter" stops nearly all UV and IR radiation and about 60% of the radiation in the visible spectrum.



Another use of gold foil :)



Source: habrahabr.ru