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The Question

(Submitted August 04, 1997)

How are the Cosmonauts in MIR protected from Ultraviolet, X-Rays and Gamma-rays?

The Answer

Cosmonauts and astronauts are protected from UV, X-rays and gamma-rays by the material in the hull and windows of their spacecraft. The primary concerns are with gamma-rays and high energy particles, such as protons accelerated by solar flares. The choice of material and thicknesses are dictated primarily by structural and thermal considerations. Metals (which are often used to meet these considerations) are generally opaque to UV, X-ray and gamma-ray radiation.

I have not been able to find the specifications of the composition and thicknesses of the hull and windows of Mir. However, according to the Shuttle Reference Manual (, the skin of the forward fuselage of the Shuttle is made of 'conventional 2024 aluminum alloy', while the crew compartment is constructed of '2219 aluminum alloy plate'. The windows are comprised of either 2 or 3 panes of glass, depending on the window location, with the panes between 0.25 and 1.3 inches and made of either aluminosilicate or fused silica.

Jim Lochner
for Ask an Astrophysicist

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