The purpose of this paper is to emphasize the need for accessibility in the assembly and maintenance of spacecraft. This is especially pertinent because accessibility to subsystems for replacement, repair, and maintenance has proven to be one of the more costly phases of preflight preparation. The most successful programs in this day and age have been when the design and manufacturing engineers work side by side around a mockup where solutions to the problems can be visually seen and solved, keeping in mind the assembly as related to accessibility. Therefore, it will be shown that in order to overcome the difficulties, designers should adapt a hard, fast ground rule that each unit must be accessible and individually removable without disturbing the other units.; Aeronautic and Space Engineering and Manufacturing Meeting, Los Angeles, Calif. Oct. 7 - 11, 1968.