1962 - Apollo Guidance Computer Commits to use ICs
The size, weight, and reduced power consumption of integrated circuits compared to discrete transistor designs justify their higher cost in military and aerospace systems.
Philco Ford alternate source of a Fairchild Micrologic IC for Apollo.
Credit: Philco-Ford Microelectronics.
The first integrated circuits were relatively slow, replaced only a handful of components, and sold for many times the price of their discrete transistor counterparts. Aerospace and military systems were among the few applications where the low power consumption and small size outweighed these drawbacks.
Against the advice of conservative advisers who warned that ICs may not be reliable, in 1962 MIT selected a Fairchild Micrologic “Type-G” (3-input NOR gate) circuit (1960 Milestone) for NASA's Apollo Guidance Computer (AGC). Philco-Ford also produced the Apollo device under license from Fairchild. Built by Raytheon, each system used about 4,000 ICs. Consuming 200,000 units at $20-30 each, the AGC was the largest user of ICs through 1965.
Engineer Bob Cook designed Series 51 DCTL, Texas Instruments first monolithic family, to meet a low-power specification for the Optical Aspect Computer on NASA’s Interplanetary Monitoring Probe (IMP). Using the SN510 and SN514 as binary counters, flip-flops, and inhibiting circuits, the IMP satellite carried the first ICs into orbit in 1963. In the UK Ferranti developed the MicroNOR logic family specifically for applications in Royal Navy systems.
TI worked with the U. S. Air Force to design a prototype “Molecular Electronic Computer” to show that 587 ICs could replace the 8,500 transistors, diodes, resistors, and capacitors required to perform the identical function in a conventional design. This led to a contract from the Autonetics Division of North American Aviation for 22 custom circuits for the Minuteman II missile guidance system in 1962. Clevite and Westinghouse also developed circuits for the Minuteman project, which by 1965 overtook NASA’s Apollo procurement as the largest single consumer of ICs.
A Molecular Electronic Computer by TI: A Microminiature Computer Designed, Developed, Tested by Texas Instruments for the U. S. Air Force. Promotional brochure, Texas Instruments (1961).
Bush, Edgar G. “The Use of Solid Circuits in Satellite Instrumentation,” Goddard Space Flight Center, Greenbelt, MD, NASA Technical Note D-1758 (July 1964).
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Hall, Eldon C. Journey to the Moon: The History of the Apollo Guidance Computer. (American Institute of Aeronautics and Astronautics, Inc., 1996).
Riordan, M & Hoddeson, L. Crystal Fire: The Birth of the Information Age. (New York: W. W. Norton, 1997) p. 272.
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