Science: Keeping the Satellites Cool

Looked at casually, the three shiny, silvery balls, 20 in. in diameter, seem to be made of polished aluminum. A closer look shows that they have an elusive iridescence, like the rainbow colors of soap bubbles. This is the only visible hint that there is something tricky about their shiny surfaces. The three balls in the Naval Research Laboratory at Washington are satellites for Project Vanguard to place on orbits circling the earth.

Heat Balance. To make observations beyond the earth's atmosphere, the instruments in a satellite must be kept fairly cool. The job...