Looking Up. NASA public domain image colelction.

Outside Mercury Mission Control, (from left) astronauts John Glenn and Alan Shepard seem to check the weather as they gather with Flight Operations Director Walt Williams and a program meteorologist. With the advent of Project Mercury and the development of the worldwide tracking network, two small additions were made to Receiver Building 3 in 1959 and the facility became known as the Mercury Control Center. One of the additions, built along the original north elevation, became the flight control room and the viewing area, while the second, along the west elevation, provided additional space for support equipment, such as data recorders.
NASA Identifier: 423361main_Shannahs_98