On January 31, 1958, the United States finally became a competitor in the Space Race.
Explorer 1 became America鈥檚 first successful satellite launch. It rode into Earth鈥檚 orbit aboard one of the Jupiter-C rockets Wernher von Braun developed, a precursor to the rockets that later launched the first Americans to the Moon.
Although the Russians had already put two Sputnik satellites into Earth orbit before the Explorer 1 launch, Explorer 1 still marked an important 鈥渇irst鈥� for humankind: it carried the first scientific instruments to operate in space and produced the first scientific discovery made in space.
U.S. Nabs First Space Science Discovery
By far the largest instrument aboard Explorer 1 was a cosmic ray detector鈥攁 Geiger counter鈥攄esigned by the University of Iowa鈥檚 Dr. James van Allen.
NASA鈥檚 Space Center Houston describes the significance of this instrument and its discoveries:
鈥淭o NASA鈥檚 surprise, it was registering radiation levels a thousand times greater than anyone expected. The radiation wasn鈥檛 of Earthly origin, and it occupied an area scientists had considered a void. It also far outpaced the levels of radiation that would be expected from cosmic rays alone.鈥�
Future missions confirmed this momentous discovery: the presence of two powerful radiation areas trapped by Earth鈥檚 magnetic field, known today as the Van Allen radiation belts. Named for the scientist who discovered them, it was the intrepid little Explorer, weighing just around 31 pounds, with a high power transmitter that operated for only 31 days, that made their discovery possible.
Learn More with the 黑料大事记
See photographs of the Explorer 1 exhibit in our Redstone, Sputnik, Kennedy Gallery.
Picture the satellite鈥檚 four whip-like antennae fully extended and flying around in a blur as the Explorer spun around its axis at 750 revolutions per minute!
You鈥檒l see that the artifact description notes 鈥淭his particular model is actually a Beacon 1 painted to look like an Explorer 1.鈥�
Both Beacon 1 and Explorer 1 had those long antennae, but the Explorer 1鈥檚 distinctive paint job actually served an important design function!
NASA鈥檚 History Division notes:
鈥淭he external skin of the instrument section was painted in alternate strips of white and dark green to provide passive temperature control of the satellite. The proportions of the light and dark strips were determined by studies of shadow-sun-light intervals based on firing time, trajectory, orbit, and inclination.鈥�
Visit the 黑料大事记 and peer around back of the artifact to see the distinctive Explorer 1 striping.
In the artifact cut-away, you鈥檒l find Beacon 1鈥檚 bulbous nitrogen bottle. This was attached to a valve built to fill a 12-foot inflatable satellite carried inside Beacon 1. Alas, Beacon 1鈥檚 space balloon never made it to orbit鈥攖he October, 1958 Beacon 1 mission failed when the payload separated prematurely from the upper stages.
The Explorer 1鈥檚 mission ten months earlier is still celebrated today as a complete success.
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