The collection consists of five folders, with the original order of the records maintained. The first four folders contain the contents of the Viking 75 Project Mission Rules, Revision AB, in ascending section and page order, dated October 4, 1977. The fifth folder contains one letter and two memoranda concerning the preparation of the Mission Rules with regard to scheduling, rules development, and rules cross-referencing. The Mission Rules were developed as decision-making aids for the Viking Flight Team (VFT) in order to control and conduct Viking spacecraft flight operations. The documents in this collection define those Mission Rules to be used by the VFT in situations where decisions about a course of action are to be made. Viking flight operations situations that do not require decision-making are not included in the Mission Rules. The Mission Rules described in the documentation are organized by Flight Team Groups within three Directorates, namely, Spacecraft Performance and Flight Path Analysis Directorate (SP and FPAD), Mission Control Directorate (MCD), and Science Analysis and Mission Planning Directorate (SA and MPD). Each rule has a prefix that indicates a classified sub-arrangement. For example, the Lander Performance Analysis Group has rules beginning with the prefix LPA. The rules are also ranked with four classes of "Criticality" numbers. Class 1 rules are of maximum critical importance, such that violation of the rule could result in spacecraft loss or damage. Violation of Class 2 rules could result in less than optimum spacecraft performance. Class 3 rules establish desirable operating standards, and Class 4 rules advise the Mission Planning Group (MPG) of constraints upon and performance estimates of the Viking Orbiter. The general format each rule follows is: (1) a statement of the rule; (2) the rationale behind the rule; (3) the rule's criticality classification; (4) the title of the individual who has the authority to waive the rule; (5) a description of the rule's implementation; (6) and a list of directorates, groups, systems, and documents that would be affected by its implementation or modification. The letter and memoranda in Folder 5 discuss the development and organization of the Mission Rules.
