50th anniversary of Explorer I launch

The first U.S satellite Explorer I was launched 50 years ago today. Amateur Radio operators were the first to receive its signals and confirm it was operating successfully.

An article in The New York Times says:

It was late in the evening, January 31, 1958, almost four months after the Soviet Union stunned the world on October 4 with the launching of Sputnik, the first artificial Earth satellite. A second, larger Sputnik soon followed, carrying a canine passenger.

The first American attempt, with the modest Vanguard 1 in December, was an embarrassing failure, immediately derided as “flopnik.”

Now it was up to a rocket assembled from German V-2 technology and American upper stages to boost the slender, bullet-shape Explorer into orbit. Liftoff from Cape Canaveral, Florida, looked good. That was progress. Vanguard had shut down a few feet above the launching pad, collapsing and exploding for all to see on live television.

But flight controllers waited and waited for a signal that Explorer had reached orbit. Tracking antennas were sparse in those days, communications unreliable.
Only after the satellite had almost completely circled the globe was its signal finally received, by alert Amateur Radio operations near Los Angeles.

The news was positive. Leaders of the Explorer team, who had been standing by in Washington, hurried to the National Academy of Sciences and proclaimed that the United States had successfully responded to the Soviet challenge. The space race was joined.

See the full New York Times article at
http://www.nytimes.com/2008/01/29/science/
space/29space.html

Jet Propulsion Laboratory - Explorer I
http://www.jpl.nasa.gov/explorer/

NASA - Explorer America's First Spacecraft http://www.nasa.gov/mission_pages/explorer/

Thanks to Martin K2UBC for spotting the NYT article