Walter M. Schirra Jr., one of America's original seven astronauts, has died at the age of 84.
Schirra, said NASA, died of natural causes at a hospital in La Jolla, Calif., near his home.
Chosen from the Navy to become one of NASA's Mercury astronauts in 1959, Wally Schirra went on to become the first man ever to make three flights in space.
Schirra was a jovial man and a serious pilot. "Levity is appropriate in a dangerous trade," he once said in a Life magazine profile.
"It was impossible to know Wally, even to meet him, without realizing at once that he was a man who relished the lighter side of life, the puns and jokes and pranks that can enliven a gathering," said NASA's administrator Michael Griffin in a statement. "But this was a distraction from the true nature of the man. His record as a pioneering space pilot shows the real stuff of which he was made. We who have inherited today's space program will always be in his debt."
The White House issued a statement from President Bush late Thursday: "His ventures into space furthered our understanding of manned space flight and helped pave the way for mankind's first journey to the Moon. Laura and I join Wally's family and friends and the NASA community in mourning the loss of an American hero."
In 1962 Schirra flew a Mercury spacecraft, which he named Sigma 7, on a six-orbit flight around the Earth.
In 1965, as commander of Gemini 6, he performed the first rendezvous in orbit with another spacecraft -- Gemini 7 -- which was already on a 14-day endurance flight. It was a complex, delicate maneuver -- one considered essential if Americans were going to make it to the moon.
Along with his co-pilot Thomas Stafford, Schirra brought his ship within six feet of Gemini 7, flown by astronauts Frank Borman and James Lovell. They flew in formation at 17,500 miles an hour, 185 miles above the Earth's surface.
Schirra's final flight, in October 1968, was the first manned test of the Apollo spacecraft that would ultimately take astronauts to the moon. Colleagues agreed that merely climbing into the cabin of Apollo 7 took nerve. Three astronauts had died in what would have been the first Apollo spacecraft to fly; they were trapped in a flash fire during a test on the launch pad in January 1967. The ship was completely redesigned.
Schirra and his crewmates, Donn Eisele and Walter Cunningham, spent 11 days flying Apollo 7, sending back the first television pictures from an American spacecraft, complaining about head colds -- and restoring NASA's confidence that it could meet President John F. Kennedy's mandate to land a man on the moon by the end of the 1960s.
"Those early pioneering flights of Mercury, the performances of Gemini and the trips to the moon established us once and for all as what I like to call a spacefaring nation," Schirra later wrote. "Like England, Spain and Portugal crossing the seas in search of their nations' greatness, so we reached for the skies and ennobled our nation."
Schirra was born and raised in northern New Jersey, in the suburbs of New York City. He fell in love with flying as a boy. He bicycled from home in Oradell, N.J., to nearby Teterboro Airport, and already knew how to fly when he went to college at the U.S. Naval Academy.
After he left NASA in 1969, he worked as a television commentator during the Apollo moon landings, served on corporate boards and was an engineering consultant. He retired to Rancho Santa Fe, Calif., near San Diego.
With his passing, only two of the original seven astronauts -- John Glenn and Scott Carpenter -- are still alive.