Flight has defined most of John Glenn's life. Born in Cambridge, Ohio, he attended nearby Muskingum College before entering a Naval Aviation program in 1942. He served as a fighter pilot in both World War II and the Korean conflict. In 1954, he completed training as a test pilot, and in 1957, Colonel John Glenn made the first transcontinental, nonstop supersonic flight.
In 1959, he was one of seven men chosen for the original group of American astronauts. Three years later, on February 20, 1962, John Glenn made history in a cramped, one-man space capsule named Friendship 7.
Glenn circled the Earth three times and splashed down safely at sea. The mission, which lasted less than five hours, made him the first American to orbit the Earth. Soviet cosmonaut Yuri Gagarin had become the first human to do so a year earlier. But Glenn says his flight was an important breakthrough for the fledgling U.S. space program in its Cold War-era space race with the Soviet Union.
"We were behind the Russians at that time," he points out. "We were very concerned that the Soviets had gotten ahead of us, technologically. We just wanted to get going, get caught up."
Besides competition from Moscow, Glenn and the other early astronauts had to worry about their rockets blowing up and the unknown physical effects of space travel.
"One of the things was, would your eyeballs change shape?" he says.
He recalls there were miniature eye charts at the top of the Friendship 7's instrument panel that he was to read every 20 minutes during flight, so space agency physicians could determine if his eyes were changing shape or not.
John Glenn left the astronaut program in 1964 to enter politics. He was elected to represent Ohio in the U.S. Senate in 1974 and kept the seat for 24 years.
On Capitol Hill, Senator Glenn was known for a keen interest in defense and nuclear non-proliferation. And he remained a staunch supporter of America's space program. He insisted, "In bad times, or even in recession time, [you have] to keep spending some money on research and looking into the future. I think that what builds this country are two things: education, number one, and number two, we've poured more of our GNP [gross national product] back into basic, fundamental research. That is where the space administration fits in."
The astronaut-turned-senator said that there were tangible benefits to space research that could help people here on Earth.
"New medicines that could be manufactured up there on a space station, pharmaceuticals that are so important to us here on Earth. That is the benefit. It is not just to do a high-wire act [exhibition] and see how far in space you can go."
He stressed that America should be getting the most it could out if its investment in space research.
John Glenn made only one flight into space, but always said that if America's space agency needed him again, he'd be ready.
"I've already told them, when they get around to doing their geriatric studies, I'm their guinea pig, and they already have a baseline [medical record] on me!"
And he did return to orbit - on the shuttle Discovery, in 1998, shortly before retiring from the Senate - becoming the oldest man to go into space. During the nine-day flight, the 77-year-old took part in several experiments assessing the effects of space travel on the elderly.
Marking NASA's 50th anniversary last year, Glenn returned to Capitol Hill and urged his former colleagues to continue funding space research and the International Space Station.
"The output here that comes from this is more advancement of science, research, new things that will benefit people right here on Earth," he pointed out, explaining that there are two kinds of exploration. "One is macro, one's micro. You can go to the moon and Mars, but at the same time you want to do the micro stuff, too, that's of value to people right here."
With a nod to the $10 billion the United States has invested in the space station, he added, "Compared to the overall cost of the vehicle [the space station] up there, the amount of money required to put more people into research is fairly small."
Since retiring from the Senate and returning from space, Glenn and his wife Annie have been putting their efforts into the John Glenn Institute for Public Service at Ohio State University. Through its programs, they work to improve the quality of public service and encourage young people to pursue careers in government… on Earth, and perhaps, one day, on Mars.