John Glenn, the first American to orbit the Earth and a former U.S. senator and war hero, has been hospitalized for more than a week, an official said on Wednesday.
Glenn, 95, is at the James Cancer Hospital at Ohio State University but does not necessarily have cancer, said Hank Wilson, spokesman at the university's John Glenn College of Public Affairs, which Glenn helped found.
"When you're 95, it's always considered serious," said Wilson, who did not have further details about Glenn's condition or his prognosis.
Glenn, the last surviving member of the original seven "Right Stuff" Mercury astronauts, had a knee replacement operation in 2011 and underwent heart surgery in 2014.
Glenn was credited with reviving U.S. pride after the Soviet Union's early domination of manned space exploration, as he became the first American to orbit the Earth on Feb. 20, 1962.
FILE - Astronaut John Glenn climbs into the Friendship 7 space capsule atop an Atlas rocket at Cape Canaveral, Fla., for the flight which made him the first American to orbit the Earth, Feb. 20, 1962.
Reaching speeds of more than 17,000 miles per hour, he circled the globe three times in just under five hours in the Friendship 7 capsule.
Glenn instantly became a hero, receiving a ticker-tape parade in New York City and the Space Congressional Medal of Honor from President John Kennedy.
His experiences as a pioneer astronaut were chronicled in the book and movie "The Right Stuff," along with the other Mercury pilots.
Glenn also became the oldest astronaut ever, returning to space at the age of 77 on Oct. 29, 1998.
Before he went into space, Glenn already had a reputation as one of the best test pilots in the country, setting a transcontinental speed record by flying from Los Angeles to New York in three hours and 23 minutes in July 1957. It was the first transcontinental flight to average supersonic speed.
He also earned six Distinguished Flying Crosses and flew more than 150 missions as a fighter pilot in World War Two and the Korean War.
Born in Cambridge, Ohio, Glenn served in the U.S. Senate as a moderate Democrat from Ohio from 1974 to 1999.