Spaceman-turned-senator John Glenn — the first American to orbit the Earth — died Thursday afternoon surrounded by his family at the Ohio State University Wexner Medical Center in Columbus after a brief illness. The last survivor of the original Mercury 7 astronauts was 95.

The Cambridge, Ohio-born John Herschel Glenn Jr. had perhaps the most storied history of any aviator in the world.

He broke the transcontinental flight speed record as a pilot with the US Marines — and flew 149 combat missions in World War II and the Korean War.

In 1962, with the US scrambling to catch up to the Soviet Union in the race for space, he became an American hero when he successfully orbited our planet — a feat accomplished a year earlier by Soviet cosmonaut Yuri Gagarin.

The Soviet Union had leaped ahead in space exploration by putting the Sputnik 1 satellite in orbit in 1957, and then launched the first man in space, Gagarin, in a 108-minute orbital flight on April 12, 1961. After two suborbital flights by Alan Shepard Jr. and Gus Grissom, it was up to Glenn to be the first American to orbit the Earth.

“Godspeed, John Glenn,” fellow astronaut Scott Carpenter radioed just before Glenn thundered off a Cape Canaveral launch pad, now a National Historic Landmark, to a place America had never been. At the time of that Feb. 20, 1962, flight, Glenn was 40 years old.

Glenn radioed to Earth, “Roger, the clock is operating, we’re under way,” as he started his 4 hours, 55 minutes and 23 seconds in space. Years later, he explained he used that all-business phrase because he didn’t feel like he had lifted off and it was the only way he knew he had launched.

During the flight, Glenn uttered a phrase that he would repeat frequently throughout life: “Zero G, and I feel fine.”

“It still seems so vivid to me,” Glenn said in a 2012 interview with the Associated Press on the 50th anniversary of the flight. “I still can sort of pseudo-feel some of those same sensations I had back in those days during launch and all.”

Glenn said he was often asked if he was afraid, and he replied, “If you are talking about fear that overcomes what you are supposed to do, no. You’ve trained very hard for those flights.”

Glenn’s ride in the cramped Friendship 7 capsule had its scary moments, however. Sensors showed his heat shield was loose after three orbits, and Mission Control worried he might burn up during re-entry when temperatures reached 3,000 degrees. But the heat shield held.

Even before then, Glenn flew in dangerous skies. He was a fighter pilot in World War II and Korea who flew low, got his plane riddled with bullets, flew with baseball great Ted Williams and earned macho nicknames during 149 combat missions. And as a test pilot, he broke aviation records.

The green-eyed, telegenic Marine even won $25,000 on the game show “Name That Tune” with a 10-year-old partner. And that was before April 6, 1959, when his life changed by being selected as one of the Mercury 7 astronauts and he instantly started attracting more than his share of the spotlight.

Glenn in later years regaled crowds with stories of NASA’s testing of would-be astronauts, from psychological tests — come up with 20 answers to the open-ended question “I am” — to surviving spinning that pushed 16 times normal gravity against his body, popping blood vessels.

But it wasn’t nearly as bad as coming to Cape Canaveral to see the first unmanned rocket test.

“We’re watching this thing go up and up and up … and all at once it blew up right over us, and that was our introduction to the Atlas,” Glenn said in 2011. “We looked at each other and wanted to have a meeting with the engineers in the morning.”

In 1959, Glenn wrote in Life magazine: “Space travel is at the frontier of my profession. It is going to be accomplished, and I want to be in on it. There is also an element of simple duty involved. I am convinced that I have something to give this project.”

In 1998, at the age of 77, he went back up, becoming the oldest man to travel in space as a crew member of the shuttle Discovery.

“To look out at this kind of creation out here and not believe in God is to me impossible,” he said of the experience.

That adventure came during the final year of his fourth term in the US Senate, the capstone of a political career that also included a brief run for the Democratic presidential nomination in 1984.

Glenn, who was married to his wife, Annie, for 73 years, earned a treasure trove of honors and medals during his military, aviation and political career.

They included the Distinguished Flying Cross, the Asiatic-Pacific Campaign Medal, the World War II Victory Medal, the Korean Service Medal, the Congressional Gold Medal, the Presidential Medal of Freedom and the Congressional Space Medal of Honor.

“John Glenn is, and always will be, Ohio’s ultimate hometown hero, and his passing today is an occasion for all of us to grieve,” said Ohio Gov. John Kasich about the first man to orbit the Earth in space.

“As we bow our heads and share our grief with his beloved wife, Annie, we must also turn to the skies, to salute his remarkable journeys and his long years of service to our state and nation.

“Though he soared deep into space and to the heights of Capitol Hill, his heart never strayed from his steadfast Ohio roots. Godspeed, John Glenn!” Kasich said.

Glenn’s body will lie in state at the Ohio Statehouse for a day, and a public memorial service will be held at Ohio State University’s Mershon Auditorium, the Columbus Dispatch reported.

He will be buried at Arlington National Cemetery near Washington, DC, in a private service, the details of which have not been announced.

Glenn also profited handsomely in business from investing in hotels near Disney World and serving as president of Royal Crown International.

But his career was also touched by controversy, as he was one of the five US senators ensnared in the Lincoln Savings & Loan and Keating Five scandal after pocketing a $200,000 contribution from Charles Keating.

Glenn and Republican Sen. John McCain were the only senators exonerated by a Senate commission, which ruled that the spaceman had exercised “poor judgment.”

With Post wires