Editing Project Mercury (section)

==Ground control==
[[File:Mercury Control crop.jpg|thumb|alt=A look inside the Mercury Control Center, Cape Canaveral, Florida. Dominated by the control board showing the position of the spacecraft above ground|Inside Control Center at Cape Canaveral (Mercury-Atlas 8)]]
The number of personnel supporting a Mercury mission was typically around 18,000, with about 15,000 people associated with recovery.{{sfn|Alexander & al.|1966|p=508}}{{sfn|Unknown|1962|p=3}}{{refn| [[T. J. O'Malley]] pushed the button to launch Glenn<ref>{{cite news|title=Thomas J. O'Malley, Who Helped Launch Glenn Into Orbit, Dies at 94|url=https://www.nytimes.com/2009/11/12/us/12omalley.html|date=November 12, 2009|first=Dennis|last=Hevesi|work=The New York Times }}</ref> while the Site Manager and Launch Conductor at Complex 14, Calvin D. Fowler, pushed the button to launch Carpenter, Schirra, and Cooper.<ref>{{cite web|url=https://richesmi.cah.ucf.edu/omeka/items/show/4975|title=Letter from General Ben I. Funk to Dr. Calvin D. Fowler (May 14, 1963)|publisher=University of Central Florida|access-date=February 1, 2023}}</ref>|group=n}} Most of the others followed the spacecraft from the World Wide Tracking Network, a chain of 18 stations placed around the equator, which was based on a network used for satellites and made ready in 1960.{{sfn|Catchpole|2001|pp=124, 461–462}} It collected data from the spacecraft and provided two-way communication between the astronaut and the ground.{{sfn|Catchpole|2001|p=117}} Each station had a range of {{convert|1300|km|nmi|order=flip|sp=us}} and a pass typically lasted 7 minutes.{{sfn|Catchpole|2001|pp=121, 126}} Mercury astronauts on the ground would take the role of Capsule Communicator, or CAPCOM, who communicated with the astronaut in orbit.{{sfn|Alexander & al.|1966|p=360}}{{sfn|Alexander & al.|1966|p=479}}{{refn|group=n|Occasionally this communication was broadcast on live TV while the spacecraft was passing over the United States.}} Data from the spacecraft were sent to the ground, processed at the Goddard Space Center by a redundant pair of transistorized [[IBM 7090]] computers<ref name="NASAComp8" /> and relayed to the [[Mercury Control Center]] at Cape Canaveral.{{sfn|Catchpole|2001|p=118}} In the Control Center, the data were displayed on boards on each side of a world map, which showed the position of the spacecraft, its [[ground track]] and the place it could land in an emergency within the next 30 minutes.{{sfn|Catchpole|2001|p=120}}

Other computers associated with ground control for Mercury included a vacuum-tube-based [[IBM 709]] system in Cape Canaveral which determined whether a mid-launch abort might be needed and where an aborting capsule would land, another IBM 709 in Bermuda which served as backup for the two IBM 7090 transistor-based machines at Goddard, and a Burroughs-GE system which provided radio guidance for the Atlas during launch.<ref name="NASAComp8" />

The World Wide Tracking Network went on to serve subsequent space programs, until it was replaced by a satellite relay system in the 1980s.{{sfn|Catchpole|2001|p=409}} Mission Control Center was moved from Cape Canaveral to [[Houston]] in 1965.{{sfn|Catchpole|2001|p=88}}

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Mercury Tracking Network 2.png|Ground track and tracking stations for Mercury-Atlas 8. Spacecraft starts from Cape Canaveral in Florida and moves east; each new orbit-track is displaced to the left due to the rotation of the Earth. It moves between latitudes 32.5° north and 32.5° south.{{sfn|Catchpole|2001|p=128}} Key: 1–6: orbit number. Yellow: launch. Black dot: tracking station. Red: range of station; Blue: landing.
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