The engineering performance of the many spacecraft subsystems was also of vital concern. Inaccurate operation in any of several areas could endanger the success of the entire mission. The performance of the attitude control system, the Earth and Sun sensors, the power system, and communications were all of critical importance. Corrective action was possible in certain subsystems where trouble could be predicted from the data or where limited breakdown had occurred.
To integrate all the varied activities necessary to accomplish the mission objectives, an organization was formed within JPL to coordinate the DSIF, the communication network, the work of engineering and scientific advisory panels, and the computer facilities required to evaluate the data.
This organization was known as the Space Flight Operations Complex. For operational purposes only, it included the Space Flight Operations Center, a Communication Center, and a Central Computing Facility (CCF). The DSIF was responsive to the requirements of the organization, but was not an integral part of it.
A space flight operations director was responsible for integrating these many functions into a world-wide Mariner space-flight organization. It was an exhausting 109-day task, one that would severely tax all the resources of JPL in terms of know-how, qualified personnel, time, and equipment before Mariner completed its encounter with Venus.
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.
