Since the birth of the Space Age a half-century ago, the space-faring nations of the world have launched thousands of satellites. Most of these artificial moons have fallen back to Earth, but others continue to circle our planet -- in some cases, long after they quit working.
The satellite that's been in orbit the longest is Vanguard 1, a silver ball that's not much bigger than a softball. It was launched 50 years ago today. It's orbited Earth almost 200,000 times, and it'll probably remain in orbit for another couple of centuries.
Vanguard was designed to measure the shape of Earth and the density of our atmosphere as part of an international project. In fact, it discovered that Earth is slightly pear shaped. But the satellite became an urgent national priority after the Soviet Union launched the first Sputnik in late 1957.
The U.S. Navy first tried to launch a Vanguard satellite on December 6th, 1957. But its booster failed just one second after launch. It crashed back onto the launch pad and exploded. The satellite flopped to the ground -- and beamed out a radio signal as if nothing had gone wrong.
After the failure, the Army got a crack at space. It launched the first American satellite into orbit on January 31st, 1958.
The second Vanguard launch attempt was another disaster. But the third try was the charm. And though it no longer works, Vanguard continues to orbit Earth -- once every two hours.
Script by Damond Benningfield, Copyright 2008
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