NASA Office of Logic Design

NASA Office of Logic Design

A scientific study of the problems of digital engineering for space flight systems,
with a view to their practical solution.

AGC Integrated Circuit Packages

Block2_FlatPacks.jpg (14918 bytes)

The documents below, courtesy of Eldon C. Hall, discuss issues with moving to the flat package for the Block II Apollo Guidance Computer, a dual 3-input NOR microcircuit.

Please see related documents on the AGC Integrated Circuits and Reliability Page.  Detailed examination of the problems associated with the packages can be found in those reports, along with die related issues.  Additionally, a partial analysis of Apollo devices has been conducted.  The AGC NOR Gate Specifications goes along with this page.

Integrated Circuit packages for the AGC

To: EG/Chief, Guidance and Control Division

From: EG32/C. D. Brady

Date: June 19, 1964



Bellcomm presents several criticisms of the flat package proposed by MIL/IL and recommends use of the TO-47 or the TO-5 transistor can (enclosure a).  The writer has been conducting a survey of both vendors and users of integrated circuits in an attempt to establish levels of confidence in the various packaging techniques.  The purpose of this memorandum is to utilize the information obtained in the survey as a basis for commenting upon the Bellcomm analysis.

The writer concludes that the flat package approach represents no greater risk than any other, and the advantages justify its use.

Integrated Circuit packages for the Block II Apollo Guidance Computer (AGC)

To: NASA Headquarters, Attention: Maj. Gen. Samuel C. Phillips, MA

From: Manager, Apollo Spacecraft Program Office, Joseph F. Shea

Date: September 9, 1964


Flat packs were initially chosen for the Block II computer to allow a reduction in guidance system weight, volume, and internal connections while eliminating the problems associated with low-level, single source production of the six-leaded Apollo TO-47 container. ... The use of flat packs was first authorized on December 30, 1963, when MIT/IL was directed to proceed with a Block II AGC by MSC TWX ...

In addition to the Block II guidance system, the Apollo program uses flat packs in the Command Module central timer.  Flat packs have also been recommended by STL for use in the LEM abort guidance system.

Based on our understanding of the status of the packaging techniques and general industry development emphasis, we cannot justify continuing six-leaded TO-47 production at a rate necessary to approach flat pack reliability confidence levels during the projected four years of AGC production.  Therefore, we will use flat packs in the guidance computer for both the CSM and LEM.

Apollo Guidance Computer and Other Computer History

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