Capcom is a term that originated in the days of the Mercury space program when spacecraft were little more than capsules. Originally named for "capsule communicator," the capcom position is traditionally a U.S. astronaut or a member of the U.S. astronaut corps, who serves in the Mission Operations Control Center as liaison with the astronauts in space.

The first capcoms were chosen from the initial group of seven astronauts selected for the Mercury project. Three-man operations teams were deployed to tracking stations around the globe. The capcom was the leader of each three-man team, and he was responsible for site mission readiness, real-time mission support, and status reporting to the Mercury control flight director. During the piloted missions, he provided communication with the astronaut in the capsule. Since there were thirteen tracking stations and only seven original astronauts, one of whom would be making the flight...