Digital Video Data Transmission System for Photometric Television

A television system to measure broadband spectral intensities of stars and their coordinates has been developed for an experiment in the Orbiting Astronomical Observatory. The satellite provides three different methods of telemetry data transmission, but none of them is really suited for video transmission: real-time digital transmission is too slow; on-board data storage has too small a capacity; and real-time analog transmission is not sufficiently accurate. By development of special digital scan techniques for television, real-time data processing on board became feasible, and real-time digital video transmission was chosen as the prime mode. Also, additional small modifications of the television system made it possible to utilize the other two remaining available methods for video transmission as backup modes of operation. The particular technique is applicable to many space experiments, and many existing satellites can be converted to a television carrier without major modification.