Joe Allen was a self-described nerd majoring in math, science and physics at DePauw University in Greencastle, Ind., when Sputnik went into orbit on Oct. 4, 1957.
Overnight, his interests no longer were considered so curious.
"It had a certain new importance given to it," the 70-year-old former NASA astronaut said. "Sputnik was recognized as a real giant in terms of technology, and it was made by a country thought to be technically backward.
"We needed our own."
A decade after the Soviet Union launched its satellite, Allen joined NASA as a scientist.
Later, he was selected to go through astronaut training, and in 1982 he made his first flight.
"As I say, it's an out of this world experience, quite literally," he said of his mission on Columbia, which marked the first time cargo was taken to space.
Between that trip, in which Allen launched two communications satellites into space, and another in 1984, Allen has spent almost three weeks of his life circling Earth.
It's an experience he shares with fewer than 500 others, and one he never dreamed possible before Sputnik was launched.
"It was a very dreamlike feeling," he said.
A half-century after Sputnik I, Allen said, he's disappointed that more astronauts haven't been trained.
He compared the space age with the evolution of air travel, which, within 50 years, went from calling the Wright brothers daredevils to commissioning throngs of pilots.
"Sadly, we're still called astronauts and cosmonauts," he said.