Adds Buzz Aldrin's statement
Former US astronaut John Glenn has died at the age of 95.
He was the first American to orbit Earth and later became the world's oldest astronaut.
The last surviving member of the original seven "Right Stuff" Mercury astronauts, he was credited with reviving US pride after the Soviet Union's early domination of manned space exploration.
He completed a three-orbit flight in the space capsule Friendship 7 on 20 February 1962.
He also had a long career as a US senator, serving for nearly a quarter century.
In 1998, he returned to space at age 77, becoming the oldest person to ever do so.
"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 Governor John Kasich said in a statement.
Glenn had been in hospital in Columbus, Ohio, for more than a week and died surrounded by his children and wife of 73 years.
Buzz Aldrin pays tribute
Buzz Aldrin, who is recovering from illness in Christchurch Hospital, has paid tribute to Glenn.
Today in a statement Dr Aldrin said he was saddened to hear that the United States had lost the pioneer of space flight and a world icon.
Dr Aldrin, who is one of the first two people to walk on the moon, was evacuated to New Zealand from Antarctica last week because he was showing signs of altitude sickness - and has since been treated for fluid on his lungs.
He is expected to be released from Christchurch Hospital in the coming days.
Entry into history
Glenn's entry into history came in early 1961 when fellow astronaut Scott Carpenter bade him "Godspeed, John Glenn" just before the Ohio native was rocketed into space for a record-breaking trip that would last just under five hours.
"Zero-G (gravity) and I feel fine," was Glenn's succinct assessment of weightlessness several minutes into his mission... Oh, and that view is tremendous."
After splashdown and recovery in the Atlantic, Glenn was treated as a hero, addressing a joint session of Congress and being feted in a New York ticker-tape parade.
As the third of seven astronauts in NASA's solo-flight Mercury programme to venture into space, he became more of a media fixture than any of the others and was known for his composure and willingness to promote the programme.
His experiences as a pioneer astronaut were chronicled in the book and movie The Right Stuff," along with the other Mercury pilots. The book's author, Tom Wolfe, called Glenn "the last true national hero America has ever had."
"I don't think of myself that way," Glenn told the New York Times in 2012 to mark the 50th anniversary of his flight.
"I get up each day and have the same problems others have at my age. As far as trying to analyse all the attention I received, I will leave that to others."
The historic flight made the astronaut a favourite of President John Kennedy and his brother Robert, who encouraged him to launch a political career that finally took off after a period as a businessman made him a millionaire.
His space career, as well as his record as a fighter pilot in WWII and the Korean War, helped propel him to the US Senate in 1974, where he represented his home state of Ohio for 24 years as a moderate Democrat.
But his star was dimmed somewhat by a Senate investigation of several senators on whether special favours were done for a major campaign contributor. He was cleared of wrongdoing.
He is expected to be buried at Arlington National Cemetery, Virginia.
- Reuters / CNN / BBC / RNZ