People
Flight Crew
Walter M. Schirra, Jr.
Pilot
Wally Schirra was a US Navy test pilot before he joined NASA in 1959 as one of the original Mercury Seven astronauts. After piloting Sigma 7 in the Mercury-Atlas 8 mission, he went on to command Gemini 6A with Tom Stafford, and Apollo 7 with Donn Eisele and Walt Cunningham.
Mission Control
Capsule Communicator
In the Mercury missions, CAPCOM was the main person to communicate with the pilot. On Mercury-Atlas 8, there were CAPCOMs operating from different stations around the world, enabling Schirra to remain in contact with the Earth through his orbits.
Flight Director
The flight director had overall operational responsibility for missions, leading their flight control team. They rarely talked directly to the capsule pilot, usually communicating through CAPCOM.