THE ravages of space are hard to bear, as NASA engineers looking at a solar
panel taken from the Mir space station have discovered. The inside had turned
into a glassy brown residue, reducing the panel鈥檚 efficiency.
In 1997, the space shuttle retrieved a section of the solar panel, which had
been attached to Mir for 10 years, giving scientists a chance to see how
radiation, micrometeorites and other hazards of space affected the panel鈥檚
performance. 鈥淚t was an ideal chance to understand the degradation,鈥� says NASA
physicist Bruce Banks, who worked on the array at the Glenn Research Center in
Cleveland, Ohio.
鈥淲hat surprised us the most was the amount of contamination on the solar
array,鈥� says Banks. Oxygen from the Earth鈥檚 upper atmosphere had reacted with an
internal layer of silicone that bonded the array together. This silicone had
turned into a brownish layer of glassy silicon oxides.
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Engineers think that the glassy oxides can absorb about 10 per cent of the
usable light striking the array, making it far less efficient. 鈥淲hen you look at
the brown coating, it鈥檚 hard to imagine that there鈥檚 no degradation,鈥� says
Banks.
The solar panels aboard Russian segments of the International Space Station
are of a similar composition. Kim de Groh, a materials science engineer at the
Glenn Research Center, believes that contamination could also be a problem for
the ISS. 鈥淚t is too late coming for any design changes,鈥� she says.