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.

2006 MAPLD International Conference

Ronald Reagan Building and International Trade Center
with a session at the Smithsonian National Air and Space Museum

Washington, D.C.

September 26-28, 2006

Session G: "Digital Engineering and Computer Design:
A Retrospective and Lessons Learned for Today's Engineers"

Logic module welding detail.  Block II logic module design was a radical departure from Block I.  A multilayer printed board provided interconnections for 60 flat-pack dual Micrologic gates.  Each logic module held two boards, 240 gates, which doubled the packaging density.  Following the all-welded construction guidelines, Block II logic gates were welded to the multilayer board’s bonding pads. (Courtesy Eldon Hall and MIT)Eldon Hall presenting "Historic Disassembly of a Block II Apollo Guidance Computer"    
Eldon Hall of the MIT Instrumentation Lab presents
"Historic Disassembly of a Block II Apollo Guidance Computer"
at Session G of the 2004 MAPLD International Conference.
  Dr. Von Braun, seated, examining a Saturn computer in the Astrionics Laboratory at the Marshall Space Flight Center.   (March 10, 1966)   Mishap and Lessons Learned: Apollo 11 Lunar Landing" - Jack Garman at Session G of the 2005 MAPLD International Conference.

Session G will be in Hemisphere A on Thursday, September 28, 2006.  This session will start at 9:30 am and last all day.  The final segment of Session G will be held at the Smithsonian National Air and Space Museum from 7 to 10 pm with Fred Haise giving the Invited History Talk.  Lunch will be served from 12:30 - 2:00 PM in the Atrium.

Note: The times of a few talks have just been adjusted slightly as the program is refined.

  Paul Ceruzzi, Smithsonian Air and Space Museum, Session Chairman

This workshop is a study of technical history for digital aerospace systems on topics that were critical in the 1950's, 1960's, and 1970's, which can provide lessons for today.  First held at MAPLD 2004 and continued during MAPLD 2005, there are a mix of technical presentations and discussions covering an entire day.  Part 1 of Session G will be held at the Ronald Reagan Building and International trade Center.  Part 2, to be held at the Smithsonian National Air and Space Museum, will include the Invited History Talk presented by Fred Haise.

Please e-mail me with any suggestions that you have or if you wish to participate in this session.

Workshop Participants and Talks:

Each talk is scheduled for approximately 30 minutes, including Questions and Answers.  The schedule is flexible.


Lunch in the  Atrium from 12:30 to 2:00 pm



See our 2006 MAPLD book signings.  Thursday during lunch and also at the Smithsonian National Air and Space Museum.

Some References (will be adding more):

Bill Tindall Section

  1. "Techniques of Controlling the Trajectory," Howard W. Tindall, Jr. Manned Spacecraft Center.

  2. "A Tindallgram," “Out of these meetings came Tindallgrams, so called because they read like no other memoranda in the Apollo Program…. They became a sensation around M.S.C. Who else but Tindall would, in an official NASA communication, describe the magnitude of a required change in spacecraft velocity as ‘teensy weensy’? Who else would entitle a memo ‘Vent bent descent, lament!’ or ‘Let’s move the recovery force a little,’ or, simply, ‘Some things about ascent from the moon’? What other engineer at Tindall’s level would, in an official NASA communication, call a top NASA official’s proposal ‘unbelievable’ and proceed to treat it as if it were the work of a crackpot?"

Other References and Reading

  1. The "Bug" Heard 'Round the World, Jack Garman NASA, Johnson Space Center ACM Software Engineering Notes October, 1981, pp. 3-10.

  2. "Flight Computer Hardware Trends," Ramon L. Alonso, MIT, and Glenn C. Randa, IBM Corp., Astronautics and Aeronautics, April 1967, pp. 30-34

  3. "Saturn V Launch Vehicle Digital Computer and Data Adapter," M. Dickinson, J. Jackson, and G. Randa, IBM Space Guidance Center, Proceedings - Fall Joint Computer Conference, 1964, pp. 501-516

  4. "Some Aspects of the Logical Design of a Control Computer: A Case Study," R.L. Alonso, H. Blair-Smith, and A.L. Hopkins, Instrumentation Laboratory, MIT, Cambridge, Mass. IEEE Transactions on Electronic Computers, December 1963, pp. 687-697

  5. "Design Principles for a General Control Computer," R. Alonso and J.H. Laning, Jr., R-276, Instrumentation Laboratory, MIT, April, 1960

  6. "Space Shuttle Main Engine Controller," Report Number NASA-TP-1932 M-360, Mattox, R. M. and White, J.B.  NASA MSFC

  7. "Computer Design Problems for the Space Environment," Dr. Joseph F. Shea, Proceedings - Conference on Spaceborne Computer Engineering, October, 1962, pp. 1-8.

  8. Journey to the Moon: The History of the Apollo Guidance Computer, Eldon C. Hall, Reston VA: American Institute of Aeronautics and Astronautics, 1996.

  9. Apollo Experience Reports

  10. "Guidance and control systems: Orbital rate drive electronics for the Apollo command module and lunar module," Parker, R. B.; and Sollock, P. E. Sep 1, 1974, NASA-TN-D-7784; JSC-S-409  Abstract: A brief record of the development and use of the orbital-rate-drive assembly in the Apollo Program is presented. This device was procured as government-furnished equipment and was used on both the lunar module and the command module. Reviews of design, development, procurement, and flight experience are included. 

  11. Annotations to Eldon Hall's Journey to the Moon," In February of 1997, Hugh Blair-Smith wrote a series of annotations to Eldon Hall's book about the history of the AGC.

  12. "Electrical Systems in Missiles and Space Vehicles," H. J. Fichtner, Astrionics Division, George C. Marshall Space Flight Center, in From PEENEMUNDE to OUTER SPACE, Commemorating the Fiftieth Birthday of Wernher von Braun, March 23, 1962, Edited by: Ernst Stuhlinger, Frederick I. Ordway, III, Jerry C. McCall, and George C. Bucher.

  13. "Special Instrumentation for Apollo Developmental Spacecraft," Alfred B. Eickmeier, NASA Manned Spacecraft Center, Houston Texas.  Aerospace Instrumentation, Volume 4, Proceedings of the Fourth International Aerospace Symposium, 1966, Edited by M.A. Perry

  14. Apollo Guidance Computer Documents

  15. Virtual AGC

  16. "The Apollo Guidance Computer: A User's View," David Scott, NASA Astronaut.  Document Courtesy of Eldon C. Hall


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