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On Mars: Exploration of the Red Planet. 1958-1978
 
 
VIKING MISSION DEFINITION NO. 2
 
 
 
[174] The Viking project definition document was another element in Jim Martin's attempt to create a viable Mars exploration activity. Revised several times, the document gave project participants a general description of the Viking missions. By August 1969, the document had been updated five times, the latest edition being called "Viking Project Mission Definition No. 2." This 21-page paper was prepared by a group working under A. Thomas Young, the science integration manager, at Langley. Three men had to approve it before it was released 11 August 1969-Gerald Soffen, project scientist; Israel Taback, engineering manager and deputy project manager; and Jim Martin. "Viking Project Definition No. 2" contained a more nearly complete description of the entry and lander science experiments that would be included in the lander capsule and the lander. These experiments had been defined through the work of the Science Steering Group, chaired by Jerry Soffen. 34
 
In August 1969, there were eight science instrument teams: orbiter imaging, biology, molecular analysis, meteorology, entry science, radio science, seismology, and ultraviolet photometry. Each of the lander experiments was further described in the "Viking Lander Science Instrument Teams Report," which served as an important reference on the state of instrument design, the scientific rationale for the experiments, and for studies that might lead to ways of increasing the scientific capability of the instruments. The instrument team report and "Viking Project Definition [175] No. 2" provided the basis for spacecraft design negotiations with Martin Marietta and the starting point for "early Project activity including the initiation of mission, spacecraft and operations design." 35, Although the mission definition was geared toward getting lander hardware design and fabrication started, it also had significant impact on the orbiter design team.
 
Henry Norris told his people at a 27 August staff meeting that the mission definition had been distributed to all the JPL division representatives. Since this was a controlling document for the project, Norris's team would have to reconcile its "resources," or budget, with its baseline definition of the orbiter. Some differences existed, for example, between the communications requirements as stated in the definition document and as pursued by the JPL engineers. "The main requirement causing a significant impact is that of the orbiter having the capability to communicate with either lander." Norris asked division representatives "to flag any other areas of disagreement," 36
 
As Norris and his staff worked on the orbiter design, the mission definition continued to evolve. A number 3 edition would be ready in January 1970 after the final selection of science investigators by NASA Headquarters in December. The number 4 version would be prepared in the early spring of 1971, reflecting any changes that came from the Viking project critical design review. Finally, some time after June 1972, "Viking Project Mission Definition No. 5" would be issued to reflect lessons learned from the Mariner 71 mission. From October 1969 onward, the mission definition documents would be used in conjunction with "project specification" documents to monitor the effort. 37 Meanwhile, the science results from Mariner 6 and 7 had to be incorporated into the Viking plans.