But while NASA was eventually to triumph in the scramble to place a man on the Moon when Neil Armstrong took his one small step in 1969, the mood among US scientists had been shrouded in gloom 12 years earlier.

"Soviet fires earth satellite into space; it is circling the globe at 18,000 mph; sphere tracked in 4 crossings over US," declared the New York Times in a double-deck front-page headline on October 5, 1957.

The news was greeted with a mixture of shock and disbelief by US astro-physicists.

"We knew the Russians were good at ballet and vodka production, but we thought that they were behind us technologically," said Simon Ramo, 94, one of the architects of America's Intercontinental ballistic missile (ICBM) program during a recent conference to mark the 50th anniversary of space exploration.

US Astronaut Harrison Schmidt, 72, one of the few men to have walked on the moon, said Sputnik's launch was the equivalent of an "intellectual earthquake."

"It was the first trigger of my interest in space," he said.

Publicly, US President Dwight Eisenhower played down the significance of Sputnik's launch, famously dismissing it as "one small ball in the air."

Privately, however, Eisenhower was more animated. Within a week he had held a secret summit with US scientists. The message was clear: win the Space Race.

Academic programs were revised with the aim of boosting the study of science; a presidential advisor for sciences was appointed; funding was boosted enormously, and eventually in July 1958, NASA came into creation. Nothing had been left to chance.

Yet despite the desperate rush to catch up, the Americans appeared to be getting left behind in the early years of the Space Race as their Soviet rivals continued to set a number of notable firsts.

By the time America finally launched its own satellite for the first time on January 31, 1958, after a series of embarrassing failures, the Soviet Union had already placed the first living creature from Earth into orbit when the dog, Laika was sent into space in November 1957.

The Soviet Union continued to set the pace, becoming the first country to land an object on the Moon in September 1959 before two years later, cosmonaut Yuri Gagarin became the first man in Space in April 1961.

One month later, Eisenhower's successor John F Kennedy set out America's objective to land the first man on the Moon.

"I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him back safely to the earth," Kennedy declared.

"No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish."

By the end of the decade, the United States was pouring billions of dollars annually into its space program and its lunar launch programs.

The payday came on July 20, 1969, when Armstrong stepped onto the Moon's surface in one of the defining moments of the 20th century.

"We had to erase the humiliation of being beaten by the Russians and go to the moon to show we were the good guys," said Burt Rutan, an entrepreneur who is one of the pioneers of private space exploration.

Astro-physicist Neil deGrasse Tyson, director of New York's Hayden Planetarium director, said the success of the lunar landings allowed the US to forget about the number of earlier defeats it had suffered at the hands of the Soviets.

"The Russians were the first to send a satellite, the first to send an animal into space, the first to send a man into space, the first to send a woman into space," he said. "They even were the first to send a black man into space, who was a Cuban."

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