The Soviet Union kicked off the Space Age 50 years ago this week by firing a basketball-size satellite called Sputnik into orbit, where its feeble "beep… beep…" would serve as a wake-up call to American dreams of preeminence and nightmares of nuclear attack.

News reports honoring this week's anniversary have made much of Soviet leaders' seemingly paradoxical lack of enthusiasm for the historic launch, in contrast to its galvanizing effect on the American public, which saw in Sputnik evidence that a space race had begun while Uncle Sam still lingered at the starting gate.

In reality, the U.S. reaction paralleled that of the Soviets in significant ways, according to Erik Conway, a NASA historian at the Jet Propulsion Laboratory in Pasadena, Calif. In both countries, aerospace engineers had to drag political leaders' attention to the stars. U.S. rocket builders, however, were aided by the popular belief that Russia's achievement demonstrated its technological superiority—and, more importantly, its nuclear reach.

That misconception, Conway says, would have dramatic consequences for the U.S. space program, resulting in the birth of NASA and the rise of space science—not to mention the first manned missions to the moon.

Sputnik was the brainchild of a group of Russian engineers, led by Chief Designer Sergei Korolev, who were tasked in 1954 with developing the nation's first intercontinental ballistic missile. The following year, Korolev was granted permission to pursue his real dream—an artificial satellite capable of exploring the origin of cosmic rays and other scientific questions—after the U.S. announced its intention to put a satellite into orbit as early as 1957 to mark the so-called International Geophysical Year.

When Korolev's team failed to complete a proposed 1,000-kilogram- (2,200-pound-) plus satellite on time, it switched gears to a bare-bones design for a much smaller craft dubbed "simple satellite," or Sputnik for short. On October 4, 1957, an R-7 ballistic missile blasted off from the plains of Kazakhstan carrying the 58-centimeter (23-inch), 83-kilogram (183-pound) aluminum orb, essentially a radio transmitter with four swept-back antennas.

The R-7 was the largest missile of its time and "much more powerful than anything the Americans had," Georgi Grechko, a Russian rocket engineer and former cosmonaut, told the Associated Press this week.

Americans—even the most technologically savvy—were stunned. "We didn't expect it that soon," says Henry Richter, a former JPL rocket engineer who worked on Explorer 1, the first successful U.S. satellite. "Nobody had ever launched a satellite before. We didn't know we could do it. Here it was suddenly up in the sky sending radio signals."

The following month, the Soviets launched the country's most famous dog, Laika, into orbit on Sputnik 2. At around 500 kilograms (1,100 pounds), the second Sputnik dwarfed the U.S. Vanguard satellite, which at 1.6 kilograms (3.5 pounds) was slated to be the first attempt, but had yet to launch. Sputnik 2 was also roughly the size of an American warhead, Conway says, but the U.S. could build a smaller warhead because it had more sophisticated electronics, adding that the Russians projected they would need a warhead more than twice that size.

"To the American public, the fact that the Soviets had much larger rockets made them look like they were ahead, but in fact we were," he says. President Eisenhower, seemingly confident that the U.S. was on track, downplayed Sputnik's significance.

The Russian leadership was similarly unimpressed when they received word of the first Sputnik launch. Russian premiere Nikita Khrushchev and other Soviet officials considered the satellite a "scientific amusement" that gave the communist country bragging rights but did not advance the main goal of an ICBM, Sergei Khrushchev, the premiere's son, told the Chicago Sun-Times this week.

The outcry in the American press convinced the Russians to plow ahead with Sputnik 2. It also forced Eisenhower to beef up plans for a U.S. satellite. In addition to the ongoing Vanguard program at the U.S. Naval Research Laboratory, JPL's Explorer became the understudy in case Vanguard failed—which it did, with flare, on December 6, 1957, rising a few feet from its launch platform before exploding. (A second attempt two months later also ended in flames.)

The scientific community got its wish for a public, civilian science program in space in October 1958, when the National Advisory Committee for Aeronautics was reborn as the National Aeronautics and Space Administration—NASA.

As a result, Conway says, U.S. astronomers got their hands on military technology that had long eluded them, such as sophisticated infrared sensors for heat-seeking missiles that could further their efforts to study the solar system.

So it was that the Space Age began. In January 1958, Explorer 1 launched from Cape Canaveral, Florida. Three years later saw the liftoff of the first Saturn rocket, which would serve as the basis for the Apollo spacecraft that would take U.S. astronauts to the moon. Now, Conway says, it was the Soviets' turn to be shocked. "They went, 'uh oh, it wasn't just propaganda. They're really doing it.'"

How the tables do turn on Earth—and in space.