FD/Chairman, Data Requirements Control PanelJUN 28 196868-PA-T-143APA/Chief, Apollo Data Priority CoordinationRelative orientation of the LM and CSM navigation bases
Unless some unexpected problem arises, it is currently planned to align the LM platform on the “D” mission for the docked DPS burns without AOT star observations. The primary reason for this is to save LM RCS fuel, although it is anticipated that overall crew procedures may also be simplified. The proposed technique involves taking advantage of the known relative orientation of the CSM and LM navigation bases. The process involved reading out gimbal angles from the command module G&N and performing a simple mathematical transformation – including the docking index reading – to determine desired LM PGNCS gimbal angles for DSKY input. A piece of informa- tion sorely needed to evaluate the quality of this procedure is a knowledge of the accuracy to which we know the relative orientation of the two navigation bases, particularly if nothing special is done to determine these values. In other words, as the spacecraft is constructed, how accurately are the navigation bases located to the principle axes of the spacecraft. It is anticipated that fairly large attitude errors can be tolerated during the docked DPS burns, making it possible to accept misalignment of two of three degrees.
I am assuming that it is from your panel that this type information should be obtained. If this is not correct, would you please let me know as soon as possible.