The accurate pointing of certain shuttle experiments can be achieved with the aid of an electro-optical attitude transfer system. By means of projected beams of collimated light, the angular attitude of such an experiment in one part of the Orbiter payload bay may be determined relative to a reference location elsewhere in the bay where the orientation is accurately known from a star tracker and/or MU. principles of attitude transfer by means of autocollimators and passive reflectors are reviewed, including reference to the evolution of electronic autocollimation techniques in the last 30 years. Possible equipment arrangements for shuttle configurations are suggested. Finally, an example of an hypothetical problem requiring three-axis attitude determination within the Orbiter bay, is examined in detail, with an indication of equipment requirements and of the accuracies attainable.
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