His was first selected as an astronaut by Nasa in 1959 and worked with the agency until 1969.
During that time he carried out projects that proved Apollo was ready to take astronauts to the moon.
His military awards included the navy distinguished service medal, three distinguished flying crosses, three air medals, two Nasa distinguished service medals, the Nasa exceptional service medal and the Philippines legion of honour.
Writing about his and fellow astronauts' work in the early years of space discovery, he said: "We shared a common dream to test the limits of man's imagination and daring.
"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. Like England, Spain and Portugal crossing the seas in search of their nations' greatness, so we reached for the skies and ennobled our nation."
Commenting on Schirra's death, Nasa administrator Michael Griffin said: "With the passing of Wally Schirra, we at Nasa note with sorrow the loss of yet another of the pioneers of human spaceflight."
"As a Mercury astronaut, Wally was a member of the first group of astronauts to be selected, often referred to as the Original Seven."
After his career with Nasa, Schirra participated in a number of television programmes and films and wrote two books.
He is survived by his wife Josephine, his daughter Suzanne and son Walter Schirra III.
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