COMMUNICATION CONTROL
The Communication Center at JPL in Pasadena was one of the most active areas during the many days and nights of the Mariner II mission. All of the teletype and radio lines from the Cape, South Africa, Australia, and Goldstone terminated in this Center. A high-speed data line bypassed the Communication Center, linking Goldstone directly with the Central Computing Facility for quick, real-time computer processing of vital flight information.
From the Communication Center, the teletype data and voice circuits were connected to the several areas within JPL where the mission-control activities were centered, and where the data output was being studied.
The Communication Center was equipped with teletype paper-page printers and paper-tape hole reperforators, which received and transmitted data-word and number groups. The teletype lines terminating at the Center included circuits from Goldstone, South Africa, Australia, and Cape Canaveral.
There were three lines to Goldstone for full-time, one-way data transmission. Duplex (simultaneous two-way) transmission was available to Woomera and South Africa on a full-time basis. In each case, a secondary circuit was provided to the overseas sites for use during critical periods and in case the primary radio-teletype circuits had transmission difficulties. These secondary circuits used different radio transmission paths in order to reduce the chance of complete loss of contact for any extended period of time.
Radio signals from Mariner are received on 85-ft. antenna.
The highly sensitive receiver (shown under test) is located in the control room of the station.
In Goldstone control room, DSIF personnel await confirmation that spacecraft has begun to scan the planet Venus.
From DSIF stations, the data are teletyped in coded format to Pasadena.
Messages are received and routed at the JPL Communications Center.
Data are routed to the digital computer at JPL.
Printout data are made available to experimenters.
Spacecraft status is posted in Operations Center.
The Mobile Tracking Station in South Africa used the Johannesburg communication facilities.
Two one-way circuits for testing and control purposes were open to Cape Canaveral from a month before until after the spacecraft was launched. Lines from the Communication Center to the Space Flight Operations Center at JPL terminated in page printers and reperforators in several locations.
Voice circuits connected all of the stations with Operations Center through the Communication Center. Long-distance radio telephone calls were placed to South Africa to establish contact before the launch sequence was started. Woomera used the Project Mercury voice circuits to the United States during launch and for three days after.