Short answers, pulled from the story.
Wally Schirra was the only astronaut to fly in the Mercury, Gemini, and Apollo programs, and the first astronaut to fly in space three times. He logged a total of 295 hours and 15 minutes in space across his three missions.
Sigma 7 was Schirra's Mercury spacecraft, which he flew on the 3rd of October 1962, completing six orbits over nine hours. The mission focused on engineering and manual spacecraft control, and Sigma 7 landed just 5 miles from the recovery carrier in the central Pacific Ocean.
On the 15th of December 1965, Schirra and Tom Stafford piloted Gemini 6A to within one foot of Gemini 7, crewed by Frank Borman and Jim Lovell, achieving the first space rendezvous in history. The two spacecraft held station for five hours before Gemini 6A deorbited on December 16th.
Schirra had developed a head cold during the Apollo 7 mission and passed it to crewmate Donn Eisele. Concerned that congestion inside a sealed spacesuit could be dangerous during reentry, Schirra proposed skipping helmets. Despite requests from Chris Kraft and Deke Slayton, Schirra, Eisele, and R. Walter Cunningham all refused and completed reentry without helmets on the 22nd of October 1968.
After leaving NASA on the 1st of July 1969, Schirra served as a CBS News consultant from 1969 to 1975, co-anchoring all seven Moon landing missions with Walter Cronkite. He also ran several businesses, founded Schirra Enterprises in January 1979, and in 1984 helped establish what became the Astronaut Scholarship Foundation to fund college scholarships for science and engineering students.
Schirra came from a family of aviators. His father, Walter M. Schirra Sr., flew bombing and reconnaissance missions for the Royal Canadian Air Force in World War I before performing as a barnstormer. His mother, Florence Shillito Schirra, performed wing walking stunts at the same county fairs in New Jersey.