During the early years at Cape Canaveral, the original Mission Control Center (MCC) consisted only of three rows, as the Mercury capsule was simple in design and construction, with missions lasting no more than 35 hours.
The first row consisted of several controllers, the BOOSTER, SURGEON, CAPCOM, RETRO, FIDO, and GUIDO.
The BOOSTER controller, depending upon the type of rocket being used, was either a engineer from the Marshall Space Flight Center (for Mercury-Redstone flights) or an Air Force engineer (for Mercury-Atlas and later Gemini-Titan flights) assigned for that mission. The BOOSTER controller’s job would last no more than six hours total and he would vacate his console after the booster was jettisoned.
The SURGEON controller, consisting of a flight surgeon (either a military or civilian doctor), monitored the astronaut’s vital signs during the flight, and if a medical need arose, could recommend treatment. The CAPCOM controller, filled by an astronaut, maintained nominal air-to-ground communications between the MCC and the orbiting spacecraft; the exception being the SURGEON or Flight Director, and only in an emergency.
The RETRO, FIDO, and GUIDO controllers monitored spacecraft trajectory and handled course changes.
The second row also consisted of several controllers, the ENVIRONMENTAL, PROCEDURES, FLIGHT, SYSTEMS, and NETWORK. The ENVIRONMENTAL controller, later called EECOM, oversaw the consumption of spacecraft oxygen and monitored pressurization, while the SYSTEMS controller, later called EGIL, monitored all other spacecraft systems, including electrical consumption. The PROCEDURES controller, first held by Gene Kranz, handled the writing of all mission milestones, “GO/NO GO” decisions, and synchronized the MCC with the launch countdowns and the Eastern Test Range. The PROCEDURES controller also handled communications, via teletype, between the MCC and the worldwide network of tracking stations and ships.
The flight director, known as FLIGHT, was ultimate supervisor of the Mission Control Center, and gave the final orbit entrance/exit, and, in emergencies, mission abort decisions. During Mercury missions, this position was held by Christopher Kraft, with John Hodge, an Englishman who came to NASA after the cancellation of the Canadian Avro Arrow project, joining the flight director ranks for the 22-orbit Mercury 9, requiring Kraft to divide Mission Control into two shifts. The flight director’s console was also the only position in the Cape MCC to have a television monitor, allowing him to see the rocket lift off from the pad. The NETWORK controller, an Air Force officer, served as the “switchboard” between the MCC, the Goddard Space Flight Center in Greenbelt, Maryland (as on-site real-time computing did not exist), and the worldwide tracking station and ship network.
The back row, consisting primarily of NASA and Department of Defense (DOD) management, was the location of the operations director (held by Walt Williams), a general or flag officer who could coordinate with the DOD on all search-and-rescue mission, and the PAO (“Shorty” Powers during Mercury), who provided minute-by-minute mission commentary for the news media and public.
In addition to the controllers in the Cape MCC, each of the manned tracking stations and the Rose Knot Victor and Coastal Sentry Quebec tracking ships, had three controllers, a CAPCOM, SURGEON, and an engineer. Unlike the Cape CAPCOM, which was always staffed by an astronaut, the tracking station/tracking ship CAPCOMs were either a NASA engineer, or an astronaut, with the latter located at stations deemed “critical” by the flight director and operations director.