A moderately sophisticated system has been developed for the calculation of the ground resolution attainable with photographic systems from space vehicles. Limitations on ground resolution are imposed by the parameters of the photographic system and those of the atmosphere. In the past it has been the system limitations which have limited the operational system. Now, however, high acuity photographic systems are being designed which could be limited by the atmosphere. Extensive calculations of ground resolution, considering atmospheric degradation, indicate that ground resolutions on the order of a few feet are probably the best regularly obtainable from space and that consequently very large optical systems may be inappropriate for space use.