The Reliability Dilemma in Space Program Packaging 640602
A look back at some of the failures of space shots shows that often the problems, whose solutions appear simple and obvious, have caused the majority of difficulties. Since experience has shown that these difficulties can generally be related to the packaging aspects, considerable emphasis is placed in this writing on packaging design and manufacturing techniques. While circuit applications have, to the most part, incorporated more standard approaches, it is quite often the package design which gives one a competitive advantage. It is for this reason that the package design considerations could not be covered in as much detail as one would have liked. The major point made here is that proper packaging design has actually a greater effect on reliability than the more theoretical aspect of a reliability program, and that power consumption, weight, size, and reliability must be considered jointly as design parameters.
The welding process and welding controls are discussed in detail as part of the packaging scheme. Here, the importance of allowing enough time for preparation of weld schedules is perhaps the major area of emphasis. With respect to the formulation of encapsulated functional units, the importance of thermo-considerations, repair and maintainability are covered.
In addition, a testing program for design evaluation of space equipment is discussed. It is indicated that present programs do not provide for demonstration of reliability to a meaningful statistical confidence and that other means have to be found to evaluate the design and manufacturing effectiveness to operational conditions. The disciplines discussed here describe such a testing program as seen by a subcontractor responsible for equipments and not systems. In this connection, it is pointed out that, in effect, testing disciplines are restrained by the testing program of the system contractor.
Finally, the effect of scheduling on the implementation of a reliability program is covered, emphasizing the detrimental effects on reliability if other tasks are improperly scheduled or if the schedule is not kept.