_It is important for a satellite to stay at the proper temperature while
it is orbiting in space. The instruments aboard it must continue to
operate properly, and one way of insuring this is to keep them from
being exposed to extreme heat or cold. We can, of course, regulate a
satellite’s temperature somewhat with various kinds of devices, and we
can see that one of its ends does not point towards the sun for too
long. But in designing the Telstar satellite we also wanted to control
temperature in an easier way: by covering the satellite’s external
surface with material with the best properties—including the right
color—for maintaining its over-all temperature at the right level._