John Herschel Glenn Jr., the first American to orbit the Earth and the last surviving of member of the nation’s original astronaut corps, died Thursday at age 95.

In 1962, Glenn blasted 162 miles into space atop a volatile Atlas rocket and was launched into the pantheon of American 20th century explorers including Charles Lindbergh and later Neil Armstrong. It was Glenn’s risky flight that paved the way for the subsequent Apollo missions that put a man on the moon seven years later.

Glenn was also a wartime hero and public servant, serving with as a Marine aviator in World War II and the Korean War and later a United States Senator.

Born in Cambridge, Ohio in 1921 to a working-class family, Glenn was an engineering student at Muskingum College when Japan attacked Pearl Harbor, drawing the United States into World War II.

Glenn joined the Marines and, in 1943, became a fighter pilot. At the controls of powerful Corsair piston-engine fighters over the Pacific, Glenn earned a reputation for precision flying and coolness under pressure.

“He could fly alongside you and tap a wing tip gently against yours,” one of Glenn’s fellow pilots reportedly said.

He fought in Korea, too, piloting F-86 fighter jets -- and famously downed three North Korean MiGs during the last nine days of fighting of the war.

He was also lucky. More than once, Glenn returned to base unharmed, but with scores of bullet holes peppering his plane. In the course of two wars, Glenn completed 149 combat missions and racked up some 9,000 total flight hours — thousands more than most military pilots achieve.

Glenn earned two Distinguished Flying Crosses and 10 Air Medals.

After Korea, he became a test pilot and, in 1957, set a speed record by flying more than 700 miles per hour across the United States in his F-8 fighter, refueling twice in mid-air.

That same year, the Soviet Union launched the world’s first artificial satellite, Sputnik, and ignited the Space Race. President Eisenhower responded by creating National Aeronautics and Space Administration (NASA) in October 1958 and, in April 1959, the infant space agency tapped Glenn, 37, to be part of Project Mercury — America's effort to put a man in orbit. The “Mercury Seven” as they came to be known were Glenn, Scott Carpenter, Gordon Cooper, Gus Grissom, Wally Schirra, Alan Shepard, and Deke Slayton.

Early space travel was dangerous, to say the least. Glenn witnessed an unmanned test rocket, complete with a simulated crew capsule, explode at an altitude of 40,000 feet. Another test he observed ended with the crew-less rocket tumbling into the ocean.

Two American astronauts preceded Glenn into space — nearly. In fact, neither Shepard nor Grissom actually escaped Earth's atmosphere. That distinction would fall to Glenn's Mercury-6 mission. Russian cosmonaut Yuri Gagarin became the first person in space in April 1961, beating the Americans by six months and injecting urgency into Glenn’s own mission.

"At the time, doctors were concerned about whether humans could even swallow in space, and would the human respiratory system even work in zero-G," recalls Joan Johnson-Freese, a space expert at the U.S. Naval War College. "Glenn’s mission in many ways confirmed that Apollo" — the NASA mission that put men on the moon — "was even possible."

On Feb. 20, 1962, Glenn climbed into a capsule perched 95 feet above the ground atop an Atlas rocket at Cape Canaveral, Florida.

“I felt exactly how you would feel if you were getting ready to launch and knew you were sitting on top of 2 million parts—all built by the lowest bidder on a government contract,” Glenn recalled later.

Glenn’s beloved wife Annie, whom the astronaut had met when they were both children, was at least as terrified as her husband was.

"I was scared," she told The Washington Post decades later. "I lost weight."

The rocket functioned. So did Glenn's heart and lungs. Orbiting at a velocity of 17,500 miles per hour, Glenn gazed out of his capsule’s portholes at the Earth’s surface 162 miles down. He snapped photos and tested communication equipment. Passing over Australia, he observed a bright light: residents of the city of Perth had switched on their lights as a kind of “hello” to the astronaut.

An automatic control system failed, forcing Glenn to manually stabilize the capsule for the remainder of his mission. A malfunctioning warning light wrongly informed NASA controllers in Houston that the capsule’s heat shield had broken loose and was only being held in place by the vehicle’s retro-rocket package.

Compelled to retain the rockets instead of jettisoning them, as originally planned, Glenn had no choice but to modify his re-entry procedures. The first American in space orbited for four hours and 56 minutes before splashing down in the Atlantic Ocean.

“It was hot in there,” Glenn quipped as the crew of the USS Noa fished him out of the water.

President John F. Kennedy rode alongside Glenn at the astronaut’s homecoming parade in Cocoa Beach, Florida. Subsequent parades in Washington, D.C. and New York City drew crowds of hundreds of thousands of people.

The plaudits were well deserved.

“It was Glenn's first orbital flight that, perhaps more than Shepard and Grissom before him, seemed to mark the beginning of NASA's ascendancy in the space race against the Soviets,” historian Rowland White, author of Into the Black, told The Daily Beast.

Glenn resigned from NASA in 1964 and, after a few years in business, entered politics. Inspired by his close friends the Kennedys, Glenn ran as a Democrat for the U.S. Senate in Ohio. He lost in 1970 but won in 1974. A primary debate in Cleveland was widely seen as the turning point for Glenn the aspiring senator. Accused by his primary opponent Howard Metzenbaum of having never had a real job, Glenn shot back.

"I ask you to go with me, as I went the other day to a Veterans Hospital, and look those men with their mangled bodies in the eye and tell them they didn't hold a job.

"You go with me to any Gold Star mother, and you look her in the eye and tell her that her son did not hold a job.”

Glenn served for 25 years in the Senate. Among his many accomplishments, he championed legislation that created inspector-general positions across government agencies. Today these internal auditors are responsible for preventing fraud, waste and abuse within their own organizations. He also helped shepherd the Nuclear Non-Proliferation Act of 1978, which required the federal government to limit the spread of weapons-grade nuclear technology.

Despite his military, scientific and political accomplishments, Glenn always said that one of his proudest moments came in the mid-1970s, when his wife Annie dedicated herself to battling a serious stutter. After years of speech therapy, in 1980 Annie delivered her very first speech -- to a women's group in Canton, Ohio.

“I have met a lot of brave people in my life,” Glenn said. “But none have been more brave than Annie.”

After being passed over to be Jimmy Carter's vice president in 1976, Glenn ran for president in 1984 but lost the Democratic primary to Walter Mondale.

Glenn retired from the U.S. Senate in January 1999, but not before pulling off one more epic feat. In October 1998, the then-77-year-old Glenn returned to space as a payload specialist on the 92nd Space Shuttle flight, making him the oldest astronaut to date. NASA required Glenn to meet the same physical-fitness standards as young astronauts. He did so handily, crediting a lifetime of jogging and weightlifting.

The old astronaut wasn't just past of the Shuttle crew, he was also an experiment.

"Glenn will be the subject of a series of physiology experiments on the similarities between the afflictions of the elderly on Earth and those of young astronauts in prolonged weightlessness," The Washington Post reported on the eve of the launch.

The launch was a media event. A quarter-million people were in the crowd, including President Bill Clinton and actor Leonardo DiCaprio. Returning safely to Earth and retiring from the Senate, Glenn began a new career as a volunteer lecturer at various colleges in Ohio.

"I think, at his core, he’s really a frustrated professor," family friend Bob McAlister told the Columbus Monthly.

Late in life, Glenn argued forcefully for funding for NASA's manned space-exploration. He liked to quote his friend and fellow astronaut Grissom. “No bucks, no Buck Rogers.”

Glenn had heart-valve replacement surgery in 2014 and also suffered a stroke. His eyesight faded. He was hospitalized in Ohio at the beginning of December.

"John Glenn is a man for the record books," Johnson-Freese said.

Glenn is survived by his wife Annie and two children, John and Carolyn.