By September 1976 the Charles Stark Draper Laboratory, Inc. Cambridge
P-357 THE HISTORY OF APOLLO ON-BOARD GUIDANCE, NAVIGATION, AND CONTROL by David G. Hoag September 1976 The Charles Stark Draper Laboratory, Inc. Cambridge, Massachusetts 02139 @ The Charles Stark Draper Laboratory, Inc. , 1976. the solar pressure force on adjustable sun vanes to drive the average speed of these wheels toward zero. Overall autonomous operation was managed on-board by a small general purpose digital computer configured by its designer, Dr. Raymond Alonso, for very low power drain except at the occasional times needing fast computation speed. A special feature of this computer was the pre-wired, read-only memory called a core rope, a configuration of particularly high storage density requiring only one magnetic core per word of memory. A four volume report of this work was published in July, 1959, and presented to the Air Force Sponsors. However, since the Air Force was disengaging from civilian space development, endeavors to interest NASA were undertaken. Dr. H. Guyford Stever, then an MIT professor, arranged a presentation with Dr. Hugh Dryden, NASA Deputy Administrator, which took place on September 15.* On November 10, NASA sent a letter of in- tent to contract the Instrumentation Laboratory for a $50,000 study to start immediately. The stated purpose was that this study would con- c tribute to the efforts of NASA's Jet Propulsion Laboratory in conducting unmanned space missions to Mars, Venus, and the Earth's moon scheduled in Vega and Centaur missions in the next few years. A relationship be- tween MIT and JPL did not evolve. JPL's approach to these deep space missions involved close ground base control with their large antenna tracking and telemetry systems, considerably different from the on- board self sufficiency method which the MIT group advocated and could best support.
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