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Satellites keep their cool

A smart coating that changes colour to reflect heat if it鈥檚 too hot and
absorb it if it鈥檚 too cold can keep satellites at exactly the right temperature.
Dramatic swings in temperature can wreak havoc with sensitive satellite sensors,
so craft are usually protected by heavy reflective slats that can be opened or
closed. David Eastham of Isis Innovation, the University of Oxford鈥檚 technology
transfer company, says the coating can do the same job as the slats, with a mass
saving of up to 5 kilograms. The temperature at which it switches from absorbing
heat to reflecting can be adjusted over a range of 100掳C to 鈭�20掳C,
to suit different satellites.