The US space agency NASA was among the first to pay tribute to the legendary astronaut who went on to serve as a lawmaker for more than two decades, calling him "a true American hero". In 1998, he became the oldest person to fly in space at age 77 (as a sitting senator).
After Glenn left NASA, he served four terms as a USA senator from the state of Ohio.
Before he became an astronaut, Glenn had heroically flown 149 combat missions in World War II and the Korean War while he served in the U.S. Marines. John Glenn, who died Thursday at age 95.
But Glenn was more modest. His death irretrievably closes the door on an era: He was the last living astronaut of the original Mercury Seven.
NEW YORK - SEPTEMBER 24: Former astronaut John Glenn looks on at the Clinton Global Initiative (CGI) on September 24, 2009 in New York City.
The last surviving member of the original seven "Right Stuff" Mercury astronauts, he was credited with reviving United States pride after the Soviet Union's early domination of manned space exploration.
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Glenn was credited with reviving US pride after the Soviet Union's early domination of manned space exploration.
"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", Ohio Gov. John R. Kasich said. "For four days, I had 21 different leads-brainwaves and respiration and EKG-21 different body parameters being recorded and sent down to the ground", noted Glenn in 2011.
He is survived by his wife Annie, his two children, Lyn and Dave and two grandchildren.
In recent years, Glenn campaigned for Democratic presidential candidates Al Gore, John Kerry and Barack Obama as well as for Sherrod Brown for U.S. Senate and Ted Strickland for governor.
With the all-business phrase, "Roger, the clock is operating, we're underway", Glenn radioed to Earth as he started his 4 hours, 55 minutes and 23 seconds in space.
Friendship 7 spacecraft launching on top of an Atlas rocket at Cape Canaveral (now Kennedy Space Centre), Florida, on 20 February 1962, carrying John Glenn.
He first ran for the U.S. Senate in 1964 but left the race when he suffered a concussion after slipping in the bathroom and hitting his head on the tub. Glenn's body will also lie in state at the Ohio Statehouse for a day prior to the memorial. The space agency agreed, training him and assigning him to mission STS-95 aboard the Space Shuttle Discovery.