Experience with Mercury Spacecraft Systems

Design of a manned spacecraft in 1958 and 1959 required that many decisions be made with no background of direct experience with similar vehicles and very little background of experience on vehicles of any type which had been exposed to the rigors of space. Under such circumstances, it was necessary to establish certain fundamental design principles which were believed to represent the proper balance between the conservatism required by the unknowns, the desired development schedule, and the extreme necessity to conserve weight. One of the foremost of the program objectives was, of course, safety. Broadly speaking, the design principles chosen to achieve the level of safety desired in such an unknown venture were
very similar to those used for manned aircraft design.