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.
A new concept for high capacity rapid access and readout photo-optical data storage system, combining recent advances in precision film movement with extreme accelerations, new optical-electronic scanning methods, and digital positioning techniques developed for an automatic machine tool control. Integration of those elements into the system is described. Immediate and potential capabilities are discussed.
The NASA Project Mercury spacecraft is tracked through its launch, orbit, and recovery phases by a world-wide network of tracking stations. The short duration of the manned flights and the paramount considerations of the astronaut's safety require a much more sophisticated ground range than is needed for unmanned flights of longer duration. Thorough testing of the ground acquisition and radar tracking equipment, prior to the spacecraft flights, was accomplished economically with boresight camera techniques, using DC-3 and C-54 aircraft specially equipped to simulate an orbiting spacecraft. Development of this test program is described, along with a discussion of the photographic equipment employed, the problems and limitations encountered and the aircraft equipment.
Current trends and recent accomplishments in the design development of instruments specifically employed in range instrumentation and tracking are reviewed; capabilities and limitations are described; some conclusions concerning the next generation of photo-optical instrumentation systems are presented.